# IMPORTANT: the same tests are run from "test_xml_etree_c" in order
# to ensure consistency between the C implementation and the Python
# implementation.
#
# For this purpose, the module-level "ET" symbol is temporarily
# monkey-patched when running the "test_xml_etree_c" test suite.

import cosmo
import copy
import html
import io
import operator
import pickle
import sys
import types
import unittest
import warnings
import weakref

from encodings import utf_16
from itertools import product
from test import support
from test.support import TESTFN, findfile, import_fresh_module, gc_collect, swap_attr

# pyET is the pure-Python implementation.
#
# ET is pyET in test_xml_etree and is the C accelerated version in
# test_xml_etree_c.
pyET = None
ET = None

SIMPLE_XMLFILE = findfile("simple.xml", subdir="xmltestdata")
try:
    SIMPLE_XMLFILE.encode("utf-8")
except UnicodeEncodeError:
    raise unittest.SkipTest("filename is not encodable to utf8")
SIMPLE_NS_XMLFILE = findfile("simple-ns.xml", subdir="xmltestdata")
UTF8_BUG_XMLFILE = findfile("expat224_utf8_bug.xml", subdir="xmltestdata")

SAMPLE_XML = """\
<body>
  <tag class='a'>text</tag>
  <tag class='b' />
  <section>
    <tag class='b' id='inner'>subtext</tag>
  </section>
</body>
"""

SAMPLE_SECTION = """\
<section>
  <tag class='b' id='inner'>subtext</tag>
  <nexttag />
  <nextsection>
    <tag />
  </nextsection>
</section>
"""

SAMPLE_XML_NS = """
<body xmlns="http://effbot.org/ns">
  <tag>text</tag>
  <tag />
  <section>
    <tag>subtext</tag>
  </section>
</body>
"""

SAMPLE_XML_NS_ELEMS = """
<root>
<h:table xmlns:h="hello">
  <h:tr>
    <h:td>Apples</h:td>
    <h:td>Bananas</h:td>
  </h:tr>
</h:table>

<f:table xmlns:f="foo">
  <f:name>African Coffee Table</f:name>
  <f:width>80</f:width>
  <f:length>120</f:length>
</f:table>
</root>
"""

ENTITY_XML = """\
<!DOCTYPE points [
<!ENTITY % user-entities SYSTEM 'user-entities.xml'>
%user-entities;
]>
<document>&entity;</document>
"""

EXTERNAL_ENTITY_XML = """\
<!DOCTYPE points [
<!ENTITY entity SYSTEM "file:///non-existing-file.xml">
]>
<document>&entity;</document>
"""

class ModuleTest(unittest.TestCase):
    def test_sanity(self):
        # Import sanity.

        from xml.etree import ElementTree
        from xml.etree import ElementInclude
        from xml.etree import ElementPath

    def test_all(self):
        names = ("xml.etree.ElementTree", "_elementtree")
        support.check__all__(self, ET, names, blacklist=("HTML_EMPTY",))


def serialize(elem, to_string=True, encoding='unicode', **options):
    if encoding != 'unicode':
        file = io.BytesIO()
    else:
        file = io.StringIO()
    tree = ET.ElementTree(elem)
    tree.write(file, encoding=encoding, **options)
    if to_string:
        return file.getvalue()
    else:
        file.seek(0)
        return file

def summarize_list(seq):
    return [elem.tag for elem in seq]


class ElementTestCase:
    @classmethod
    def setUpClass(cls):
        cls.modules = {pyET, ET}

    def pickleRoundTrip(self, obj, name, dumper, loader, proto):
        save_m = sys.modules[name]
        try:
            sys.modules[name] = dumper
            temp = pickle.dumps(obj, proto)
            sys.modules[name] = loader
            result = pickle.loads(temp)
        except pickle.PicklingError as pe:
            # pyET must be second, because pyET may be (equal to) ET.
            human = dict([(ET, "cET"), (pyET, "pyET")])
            raise support.TestFailed("Failed to round-trip %r from %r to %r"
                                     % (obj,
                                        human.get(dumper, dumper),
                                        human.get(loader, loader))) from pe
        finally:
            sys.modules[name] = save_m
        return result

    def assertEqualElements(self, alice, bob):
        self.assertIsInstance(alice, (ET.Element, pyET.Element))
        self.assertIsInstance(bob, (ET.Element, pyET.Element))
        self.assertEqual(len(list(alice)), len(list(bob)))
        for x, y in zip(alice, bob):
            self.assertEqualElements(x, y)
        properties = operator.attrgetter('tag', 'tail', 'text', 'attrib')
        self.assertEqual(properties(alice), properties(bob))

# --------------------------------------------------------------------
# element tree tests

class ElementTreeTest(unittest.TestCase):

    def serialize_check(self, elem, expected):
        self.assertEqual(serialize(elem), expected)

    def test_interface(self):
        # Test element tree interface.

        def check_string(string):
            len(string)
            for char in string:
                self.assertEqual(len(char), 1,
                        msg="expected one-character string, got %r" % char)
            new_string = string + ""
            new_string = string + " "
            string[:0]

        def check_mapping(mapping):
            len(mapping)
            keys = mapping.keys()
            items = mapping.items()
            for key in keys:
                item = mapping[key]
            mapping["key"] = "value"
            self.assertEqual(mapping["key"], "value",
                    msg="expected value string, got %r" % mapping["key"])

        def check_element(element):
            self.assertTrue(ET.iselement(element), msg="not an element")
            direlem = dir(element)
            for attr in 'tag', 'attrib', 'text', 'tail':
                self.assertTrue(hasattr(element, attr),
                        msg='no %s member' % attr)
                self.assertIn(attr, direlem,
                        msg='no %s visible by dir' % attr)

            check_string(element.tag)
            check_mapping(element.attrib)
            if element.text is not None:
                check_string(element.text)
            if element.tail is not None:
                check_string(element.tail)
            for elem in element:
                check_element(elem)

        element = ET.Element("tag")
        check_element(element)
        tree = ET.ElementTree(element)
        check_element(tree.getroot())
        element = ET.Element("t\xe4g", key="value")
        tree = ET.ElementTree(element)
        self.assertRegex(repr(element), r"^<Element 't\xe4g' at 0x.*>$")
        element = ET.Element("tag", key="value")

        # Make sure all standard element methods exist.

        def check_method(method):
            self.assertTrue(hasattr(method, '__call__'),
                    msg="%s not callable" % method)

        check_method(element.append)
        check_method(element.extend)
        check_method(element.insert)
        check_method(element.remove)
        check_method(element.getchildren)
        check_method(element.find)
        check_method(element.iterfind)
        check_method(element.findall)
        check_method(element.findtext)
        check_method(element.clear)
        check_method(element.get)
        check_method(element.set)
        check_method(element.keys)
        check_method(element.items)
        check_method(element.iter)
        check_method(element.itertext)
        check_method(element.getiterator)

        # These methods return an iterable. See bug 6472.

        def check_iter(it):
            check_method(it.__next__)

        check_iter(element.iterfind("tag"))
        check_iter(element.iterfind("*"))
        check_iter(tree.iterfind("tag"))
        check_iter(tree.iterfind("*"))

        # These aliases are provided:

        self.assertEqual(ET.XML, ET.fromstring)
        self.assertEqual(ET.PI, ET.ProcessingInstruction)

    def test_set_attribute(self):
        element = ET.Element('tag')

        self.assertEqual(element.tag, 'tag')
        element.tag = 'Tag'
        self.assertEqual(element.tag, 'Tag')
        element.tag = 'TAG'
        self.assertEqual(element.tag, 'TAG')

        self.assertIsNone(element.text)
        element.text = 'Text'
        self.assertEqual(element.text, 'Text')
        element.text = 'TEXT'
        self.assertEqual(element.text, 'TEXT')

        self.assertIsNone(element.tail)
        element.tail = 'Tail'
        self.assertEqual(element.tail, 'Tail')
        element.tail = 'TAIL'
        self.assertEqual(element.tail, 'TAIL')

        self.assertEqual(element.attrib, {})
        element.attrib = {'a': 'b', 'c': 'd'}
        self.assertEqual(element.attrib, {'a': 'b', 'c': 'd'})
        element.attrib = {'A': 'B', 'C': 'D'}
        self.assertEqual(element.attrib, {'A': 'B', 'C': 'D'})

    def test_simpleops(self):
        # Basic method sanity checks.

        elem = ET.XML("<body><tag/></body>")
        self.serialize_check(elem, '<body><tag /></body>')
        e = ET.Element("tag2")
        elem.append(e)
        self.serialize_check(elem, '<body><tag /><tag2 /></body>')
        elem.remove(e)
        self.serialize_check(elem, '<body><tag /></body>')
        elem.insert(0, e)
        self.serialize_check(elem, '<body><tag2 /><tag /></body>')
        elem.remove(e)
        elem.extend([e])
        self.serialize_check(elem, '<body><tag /><tag2 /></body>')
        elem.remove(e)

        element = ET.Element("tag", key="value")
        self.serialize_check(element, '<tag key="value" />') # 1
        subelement = ET.Element("subtag")
        element.append(subelement)
        self.serialize_check(element, '<tag key="value"><subtag /></tag>') # 2
        element.insert(0, subelement)
        self.serialize_check(element,
                '<tag key="value"><subtag /><subtag /></tag>') # 3
        element.remove(subelement)
        self.serialize_check(element, '<tag key="value"><subtag /></tag>') # 4
        element.remove(subelement)
        self.serialize_check(element, '<tag key="value" />') # 5
        with self.assertRaises(ValueError) as cm:
            element.remove(subelement)
        self.assertEqual(str(cm.exception), 'list.remove(x): x not in list')
        self.serialize_check(element, '<tag key="value" />') # 6
        element[0:0] = [subelement, subelement, subelement]
        self.serialize_check(element[1], '<subtag />')
        self.assertEqual(element[1:9], [element[1], element[2]])
        self.assertEqual(element[:9:2], [element[0], element[2]])
        del element[1:2]
        self.serialize_check(element,
                '<tag key="value"><subtag /><subtag /></tag>')

    def test_cdata(self):
        # Test CDATA handling (etc).

        self.serialize_check(ET.XML("<tag>hello</tag>"),
                '<tag>hello</tag>')
        self.serialize_check(ET.XML("<tag>&#104;&#101;&#108;&#108;&#111;</tag>"),
                '<tag>hello</tag>')
        self.serialize_check(ET.XML("<tag><![CDATA[hello]]></tag>"),
                '<tag>hello</tag>')

    def test_file_init(self):
        stringfile = io.BytesIO(SAMPLE_XML.encode("utf-8"))
        tree = ET.ElementTree(file=stringfile)
        self.assertEqual(tree.find("tag").tag, 'tag')
        self.assertEqual(tree.find("section/tag").tag, 'tag')

        tree = ET.ElementTree(file=SIMPLE_XMLFILE)
        self.assertEqual(tree.find("element").tag, 'element')
        self.assertEqual(tree.find("element/../empty-element").tag,
                'empty-element')

    def test_path_cache(self):
        # Check that the path cache behaves sanely.

        from xml.etree import ElementPath

        elem = ET.XML(SAMPLE_XML)
        for i in range(10): ET.ElementTree(elem).find('./'+str(i))
        cache_len_10 = len(ElementPath._cache)
        for i in range(10): ET.ElementTree(elem).find('./'+str(i))
        self.assertEqual(len(ElementPath._cache), cache_len_10)
        for i in range(20): ET.ElementTree(elem).find('./'+str(i))
        self.assertGreater(len(ElementPath._cache), cache_len_10)
        for i in range(600): ET.ElementTree(elem).find('./'+str(i))
        self.assertLess(len(ElementPath._cache), 500)

    def test_copy(self):
        # Test copy handling (etc).

        import copy
        e1 = ET.XML("<tag>hello<foo/></tag>")
        e2 = copy.copy(e1)
        e3 = copy.deepcopy(e1)
        e1.find("foo").tag = "bar"
        self.serialize_check(e1, '<tag>hello<bar /></tag>')
        self.serialize_check(e2, '<tag>hello<bar /></tag>')
        self.serialize_check(e3, '<tag>hello<foo /></tag>')

    def test_attrib(self):
        # Test attribute handling.

        elem = ET.Element("tag")
        elem.get("key") # 1.1
        self.assertEqual(elem.get("key", "default"), 'default') # 1.2

        elem.set("key", "value")
        self.assertEqual(elem.get("key"), 'value') # 1.3

        elem = ET.Element("tag", key="value")
        self.assertEqual(elem.get("key"), 'value') # 2.1
        self.assertEqual(elem.attrib, {'key': 'value'}) # 2.2

        attrib = {"key": "value"}
        elem = ET.Element("tag", attrib)
        attrib.clear() # check for aliasing issues
        self.assertEqual(elem.get("key"), 'value') # 3.1
        self.assertEqual(elem.attrib, {'key': 'value'}) # 3.2

        attrib = {"key": "value"}
        elem = ET.Element("tag", **attrib)
        attrib.clear() # check for aliasing issues
        self.assertEqual(elem.get("key"), 'value') # 4.1
        self.assertEqual(elem.attrib, {'key': 'value'}) # 4.2

        elem = ET.Element("tag", {"key": "other"}, key="value")
        self.assertEqual(elem.get("key"), 'value') # 5.1
        self.assertEqual(elem.attrib, {'key': 'value'}) # 5.2

        elem = ET.Element('test')
        elem.text = "aa"
        elem.set('testa', 'testval')
        elem.set('testb', 'test2')
        self.assertEqual(ET.tostring(elem),
                b'<test testa="testval" testb="test2">aa</test>')
        self.assertEqual(sorted(elem.keys()), ['testa', 'testb'])
        self.assertEqual(sorted(elem.items()),
                [('testa', 'testval'), ('testb', 'test2')])
        self.assertEqual(elem.attrib['testb'], 'test2')
        elem.attrib['testb'] = 'test1'
        elem.attrib['testc'] = 'test2'
        self.assertEqual(ET.tostring(elem),
                b'<test testa="testval" testb="test1" testc="test2">aa</test>')

        elem = ET.Element('test')
        elem.set('a', '\r')
        elem.set('b', '\r\n')
        elem.set('c', '\t\n\r ')
        elem.set('d', '\n\n')
        self.assertEqual(ET.tostring(elem),
                b'<test a="&#10;" b="&#10;" c="&#09;&#10;&#10; " d="&#10;&#10;" />')

    def test_makeelement(self):
        # Test makeelement handling.

        elem = ET.Element("tag")
        attrib = {"key": "value"}
        subelem = elem.makeelement("subtag", attrib)
        self.assertIsNot(subelem.attrib, attrib, msg="attrib aliasing")
        elem.append(subelem)
        self.serialize_check(elem, '<tag><subtag key="value" /></tag>')

        elem.clear()
        self.serialize_check(elem, '<tag />')
        elem.append(subelem)
        self.serialize_check(elem, '<tag><subtag key="value" /></tag>')
        elem.extend([subelem, subelem])
        self.serialize_check(elem,
            '<tag><subtag key="value" /><subtag key="value" /><subtag key="value" /></tag>')
        elem[:] = [subelem]
        self.serialize_check(elem, '<tag><subtag key="value" /></tag>')
        elem[:] = tuple([subelem])
        self.serialize_check(elem, '<tag><subtag key="value" /></tag>')

    def test_parsefile(self):
        # Test parsing from file.

        tree = ET.parse(SIMPLE_XMLFILE)
        stream = io.StringIO()
        tree.write(stream, encoding='unicode')
        self.assertEqual(stream.getvalue(),
                '<root>\n'
                '   <element key="value">text</element>\n'
                '   <element>text</element>tail\n'
                '   <empty-element />\n'
                '</root>')
        tree = ET.parse(SIMPLE_NS_XMLFILE)
        stream = io.StringIO()
        tree.write(stream, encoding='unicode')
        self.assertEqual(stream.getvalue(),
                '<ns0:root xmlns:ns0="namespace">\n'
                '   <ns0:element key="value">text</ns0:element>\n'
                '   <ns0:element>text</ns0:element>tail\n'
                '   <ns0:empty-element />\n'
                '</ns0:root>')

        with open(SIMPLE_XMLFILE) as f:
            data = f.read()

        parser = ET.XMLParser()
        self.assertRegex(parser.version, r'^Expat ')
        parser.feed(data)
        self.serialize_check(parser.close(),
                '<root>\n'
                '   <element key="value">text</element>\n'
                '   <element>text</element>tail\n'
                '   <empty-element />\n'
                '</root>')

        target = ET.TreeBuilder()
        parser = ET.XMLParser(target=target)
        parser.feed(data)
        self.serialize_check(parser.close(),
                '<root>\n'
                '   <element key="value">text</element>\n'
                '   <element>text</element>tail\n'
                '   <empty-element />\n'
                '</root>')

    def test_parseliteral(self):
        element = ET.XML("<html><body>text</body></html>")
        self.assertEqual(ET.tostring(element, encoding='unicode'),
                '<html><body>text</body></html>')
        element = ET.fromstring("<html><body>text</body></html>")
        self.assertEqual(ET.tostring(element, encoding='unicode'),
                '<html><body>text</body></html>')
        sequence = ["<html><body>", "text</bo", "dy></html>"]
        element = ET.fromstringlist(sequence)
        self.assertEqual(ET.tostring(element),
                b'<html><body>text</body></html>')
        self.assertEqual(b"".join(ET.tostringlist(element)),
                b'<html><body>text</body></html>')
        self.assertEqual(ET.tostring(element, "ascii"),
                b"<?xml version='1.0' encoding='ascii'?>\n"
                b"<html><body>text</body></html>")
        _, ids = ET.XMLID("<html><body>text</body></html>")
        self.assertEqual(len(ids), 0)
        _, ids = ET.XMLID("<html><body id='body'>text</body></html>")
        self.assertEqual(len(ids), 1)
        self.assertEqual(ids["body"].tag, 'body')

    def test_iterparse(self):
        # Test iterparse interface.

        iterparse = ET.iterparse

        context = iterparse(SIMPLE_XMLFILE)
        action, elem = next(context)
        self.assertEqual((action, elem.tag), ('end', 'element'))
        self.assertEqual([(action, elem.tag) for action, elem in context], [
                ('end', 'element'),
                ('end', 'empty-element'),
                ('end', 'root'),
            ])
        self.assertEqual(context.root.tag, 'root')

        context = iterparse(SIMPLE_NS_XMLFILE)
        self.assertEqual([(action, elem.tag) for action, elem in context], [
                ('end', '{namespace}element'),
                ('end', '{namespace}element'),
                ('end', '{namespace}empty-element'),
                ('end', '{namespace}root'),
            ])

        events = ()
        context = iterparse(SIMPLE_XMLFILE, events)
        self.assertEqual([(action, elem.tag) for action, elem in context], [])

        events = ()
        context = iterparse(SIMPLE_XMLFILE, events=events)
        self.assertEqual([(action, elem.tag) for action, elem in context], [])

        events = ("start", "end")
        context = iterparse(SIMPLE_XMLFILE, events)
        self.assertEqual([(action, elem.tag) for action, elem in context], [
                ('start', 'root'),
                ('start', 'element'),
                ('end', 'element'),
                ('start', 'element'),
                ('end', 'element'),
                ('start', 'empty-element'),
                ('end', 'empty-element'),
                ('end', 'root'),
            ])

        events = ("start", "end", "start-ns", "end-ns")
        context = iterparse(SIMPLE_NS_XMLFILE, events)
        self.assertEqual([(action, elem.tag) if action in ("start", "end")
                                             else (action, elem)
                          for action, elem in context], [
                ('start-ns', ('', 'namespace')),
                ('start', '{namespace}root'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}empty-element'),
                ('end', '{namespace}empty-element'),
                ('end', '{namespace}root'),
                ('end-ns', None),
            ])

        events = ('start-ns', 'end-ns')
        context = iterparse(io.StringIO(r"<root xmlns=''/>"), events)
        res = [action for action, elem in context]
        self.assertEqual(res, ['start-ns', 'end-ns'])

        events = ("start", "end", "bogus")
        with open(SIMPLE_XMLFILE, "rb") as f:
            with self.assertRaises(ValueError) as cm:
                iterparse(f, events)
            self.assertFalse(f.closed)
        self.assertEqual(str(cm.exception), "unknown event 'bogus'")

        with support.check_no_resource_warning(self):
            with self.assertRaises(ValueError) as cm:
                iterparse(SIMPLE_XMLFILE, events)
            self.assertEqual(str(cm.exception), "unknown event 'bogus'")
            del cm

        source = io.BytesIO(
            b"<?xml version='1.0' encoding='iso-8859-1'?>\n"
            b"<body xmlns='http://&#233;ffbot.org/ns'\n"
            b"      xmlns:cl\xe9='http://effbot.org/ns'>text</body>\n")
        events = ("start-ns",)
        context = iterparse(source, events)
        self.assertEqual([(action, elem) for action, elem in context], [
                ('start-ns', ('', 'http://\xe9ffbot.org/ns')),
                ('start-ns', ('cl\xe9', 'http://effbot.org/ns')),
            ])

        source = io.StringIO("<document />junk")
        it = iterparse(source)
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'document'))
        with self.assertRaises(ET.ParseError) as cm:
            next(it)
        self.assertEqual(str(cm.exception),
                'junk after document element: line 1, column 12')

        self.addCleanup(support.unlink, TESTFN)
        with open(TESTFN, "wb") as f:
            f.write(b"<document />junk")
        it = iterparse(TESTFN)
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'document'))
        with support.check_no_resource_warning(self):
            with self.assertRaises(ET.ParseError) as cm:
                next(it)
            self.assertEqual(str(cm.exception),
                    'junk after document element: line 1, column 12')
            del cm, it

    def test_writefile(self):
        elem = ET.Element("tag")
        elem.text = "text"
        self.serialize_check(elem, '<tag>text</tag>')
        ET.SubElement(elem, "subtag").text = "subtext"
        self.serialize_check(elem, '<tag>text<subtag>subtext</subtag></tag>')

        # Test tag suppression
        elem.tag = None
        self.serialize_check(elem, 'text<subtag>subtext</subtag>')
        elem.insert(0, ET.Comment("comment"))
        self.serialize_check(elem,
                'text<!--comment--><subtag>subtext</subtag>')     # assumes 1.3

        elem[0] = ET.PI("key", "value")
        self.serialize_check(elem, 'text<?key value?><subtag>subtext</subtag>')

    def test_custom_builder(self):
        # Test parser w. custom builder.

        with open(SIMPLE_XMLFILE) as f:
            data = f.read()
        class Builder(list):
            def start(self, tag, attrib):
                self.append(("start", tag))
            def end(self, tag):
                self.append(("end", tag))
            def data(self, text):
                pass
        builder = Builder()
        parser = ET.XMLParser(target=builder)
        parser.feed(data)
        self.assertEqual(builder, [
                ('start', 'root'),
                ('start', 'element'),
                ('end', 'element'),
                ('start', 'element'),
                ('end', 'element'),
                ('start', 'empty-element'),
                ('end', 'empty-element'),
                ('end', 'root'),
            ])

        with open(SIMPLE_NS_XMLFILE) as f:
            data = f.read()
        class Builder(list):
            def start(self, tag, attrib):
                self.append(("start", tag))
            def end(self, tag):
                self.append(("end", tag))
            def data(self, text):
                pass
            def pi(self, target, data):
                self.append(("pi", target, data))
            def comment(self, data):
                self.append(("comment", data))
        builder = Builder()
        parser = ET.XMLParser(target=builder)
        parser.feed(data)
        self.assertEqual(builder, [
                ('pi', 'pi', 'data'),
                ('comment', ' comment '),
                ('start', '{namespace}root'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}empty-element'),
                ('end', '{namespace}empty-element'),
                ('end', '{namespace}root'),
            ])


    def test_getchildren(self):
        # Test Element.getchildren()

        with open(SIMPLE_XMLFILE, "rb") as f:
            tree = ET.parse(f)
        self.assertEqual([summarize_list(elem.getchildren())
                          for elem in tree.getroot().iter()], [
                ['element', 'element', 'empty-element'],
                [],
                [],
                [],
            ])
        self.assertEqual([summarize_list(elem.getchildren())
                          for elem in tree.getiterator()], [
                ['element', 'element', 'empty-element'],
                [],
                [],
                [],
            ])

        elem = ET.XML(SAMPLE_XML)
        self.assertEqual(len(elem.getchildren()), 3)
        self.assertEqual(len(elem[2].getchildren()), 1)
        self.assertEqual(elem[:], elem.getchildren())
        child1 = elem[0]
        child2 = elem[2]
        del elem[1:2]
        self.assertEqual(len(elem.getchildren()), 2)
        self.assertEqual(child1, elem[0])
        self.assertEqual(child2, elem[1])
        elem[0:2] = [child2, child1]
        self.assertEqual(child2, elem[0])
        self.assertEqual(child1, elem[1])
        self.assertNotEqual(child1, elem[0])
        elem.clear()
        self.assertEqual(elem.getchildren(), [])

    def test_writestring(self):
        elem = ET.XML("<html><body>text</body></html>")
        self.assertEqual(ET.tostring(elem), b'<html><body>text</body></html>')
        elem = ET.fromstring("<html><body>text</body></html>")
        self.assertEqual(ET.tostring(elem), b'<html><body>text</body></html>')

    def test_encoding(self):
        def check(encoding, body=''):
            xml = ("<?xml version='1.0' encoding='%s'?><xml>%s</xml>" %
                   (encoding, body))
            self.assertEqual(ET.XML(xml.encode(encoding)).text, body)
            self.assertEqual(ET.XML(xml).text, body)
        check("ascii", 'a')
        check("us-ascii", 'a')
        check("iso-8859-1", '\xbd')
        check("iso-8859-15", '\u20ac')
        check("cp437", '\u221a')
        check("mac-roman", '\u02da')

        def xml(encoding):
            return "<?xml version='1.0' encoding='%s'?><xml />" % encoding
        def bxml(encoding):
            return xml(encoding).encode(encoding)
        supported_encodings = [
            'ascii', 'utf-8', 'utf-8-sig', 'utf-16', 'utf-16be', 'utf-16le',
            'iso8859-1', 'iso8859-2', 'iso8859-3', 'iso8859-4', 'iso8859-5',
            'iso8859-6', 'iso8859-7', 'iso8859-8', 'iso8859-9', 'iso8859-10',
            'iso8859-13', 'iso8859-14', 'iso8859-15', 'iso8859-16',
            'cp437', 'cp720', 'cp737', 'cp775', 'cp850', 'cp852',
            'cp855', 'cp856', 'cp857', 'cp858', 'cp860', 'cp861', 'cp862',
            'cp863', 'cp865', 'cp866', 'cp869', 'cp874', 'cp1006', 'cp1125',
            'cp1250', 'cp1251', 'cp1252', 'cp1253', 'cp1254', 'cp1255',
            'cp1256', 'cp1257', 'cp1258',
            'mac-cyrillic', 'mac-greek', 'mac-iceland', 'mac-latin2',
            'mac-roman', 'mac-turkish',
            'iso2022-jp', 'iso2022-jp-1', 'iso2022-jp-2', 'iso2022-jp-2004',
            'iso2022-jp-3', 'iso2022-jp-ext',
            'koi8-r', 'koi8-t', 'koi8-u', 'kz1048',
            'hz', 'ptcp154',
        ]
        for encoding in supported_encodings:
            self.assertEqual(ET.tostring(ET.XML(bxml(encoding))), b'<xml />')

        unsupported_ascii_compatible_encodings = [
            'big5', 'big5hkscs',
            'cp932', 'cp949', 'cp950',
            'euc-jp', 'euc-jis-2004', 'euc-jisx0213', 'euc-kr',
            'gb2312', 'gbk', 'gb18030',
            'iso2022-kr', 'johab',
            'shift-jis', 'shift-jis-2004', 'shift-jisx0213',
            'utf-7',
        ]
        for encoding in unsupported_ascii_compatible_encodings:
            self.assertRaises(ValueError, ET.XML, bxml(encoding))

        unsupported_ascii_incompatible_encodings = [
            'cp037', 'cp424', 'cp500', 'cp864', 'cp875', 'cp1026', 'cp1140',
            'utf_32', 'utf_32_be', 'utf_32_le',
        ]
        for encoding in unsupported_ascii_incompatible_encodings:
            self.assertRaises(ET.ParseError, ET.XML, bxml(encoding))

        self.assertRaises(ValueError, ET.XML, xml('undefined').encode('ascii'))
        self.assertRaises(LookupError, ET.XML, xml('xxx').encode('ascii'))

    def test_methods(self):
        # Test serialization methods.

        e = ET.XML("<html><link/><script>1 &lt; 2</script></html>")
        e.tail = "\n"
        self.assertEqual(serialize(e),
                '<html><link /><script>1 &lt; 2</script></html>\n')
        self.assertEqual(serialize(e, method=None),
                '<html><link /><script>1 &lt; 2</script></html>\n')
        self.assertEqual(serialize(e, method="xml"),
                '<html><link /><script>1 &lt; 2</script></html>\n')
        self.assertEqual(serialize(e, method="html"),
                '<html><link><script>1 < 2</script></html>\n')
        self.assertEqual(serialize(e, method="text"), '1 < 2\n')

    def test_issue18347(self):
        e = ET.XML('<html><CamelCase>text</CamelCase></html>')
        self.assertEqual(serialize(e),
                '<html><CamelCase>text</CamelCase></html>')
        self.assertEqual(serialize(e, method="html"),
                '<html><CamelCase>text</CamelCase></html>')

    def test_entity(self):
        # Test entity handling.

        # 1) good entities

        e = ET.XML("<document title='&#x8230;'>test</document>")
        self.assertEqual(serialize(e, encoding="us-ascii"),
                b'<document title="&#33328;">test</document>')
        self.serialize_check(e, '<document title="\u8230">test</document>')

        # 2) bad entities

        with self.assertRaises(ET.ParseError) as cm:
            ET.XML("<document>&entity;</document>")
        self.assertEqual(str(cm.exception),
                'undefined entity: line 1, column 10')

        with self.assertRaises(ET.ParseError) as cm:
            ET.XML(ENTITY_XML)
        self.assertEqual(str(cm.exception),
                'undefined entity &entity;: line 5, column 10')

        # 3) custom entity

        parser = ET.XMLParser()
        parser.entity["entity"] = "text"
        parser.feed(ENTITY_XML)
        root = parser.close()
        self.serialize_check(root, '<document>text</document>')

        # 4) external (SYSTEM) entity

        with self.assertRaises(ET.ParseError) as cm:
            ET.XML(EXTERNAL_ENTITY_XML)
        self.assertEqual(str(cm.exception),
                'undefined entity &entity;: line 4, column 10')

    def test_namespace(self):
        # Test namespace issues.

        # 1) xml namespace

        elem = ET.XML("<tag xml:lang='en' />")
        self.serialize_check(elem, '<tag xml:lang="en" />') # 1.1

        # 2) other "well-known" namespaces

        elem = ET.XML("<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#' />")
        self.serialize_check(elem,
            '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" />') # 2.1

        elem = ET.XML("<html:html xmlns:html='http://www.w3.org/1999/xhtml' />")
        self.serialize_check(elem,
            '<html:html xmlns:html="http://www.w3.org/1999/xhtml" />') # 2.2

        elem = ET.XML("<soap:Envelope xmlns:soap='http://schemas.xmlsoap.org/soap/envelope' />")
        self.serialize_check(elem,
            '<ns0:Envelope xmlns:ns0="http://schemas.xmlsoap.org/soap/envelope" />') # 2.3

        # 3) unknown namespaces
        elem = ET.XML(SAMPLE_XML_NS)
        self.serialize_check(elem,
            '<ns0:body xmlns:ns0="http://effbot.org/ns">\n'
            '  <ns0:tag>text</ns0:tag>\n'
            '  <ns0:tag />\n'
            '  <ns0:section>\n'
            '    <ns0:tag>subtext</ns0:tag>\n'
            '  </ns0:section>\n'
            '</ns0:body>')

    def test_qname(self):
        # Test QName handling.

        # 1) decorated tags

        elem = ET.Element("{uri}tag")
        self.serialize_check(elem, '<ns0:tag xmlns:ns0="uri" />') # 1.1
        elem = ET.Element(ET.QName("{uri}tag"))
        self.serialize_check(elem, '<ns0:tag xmlns:ns0="uri" />') # 1.2
        elem = ET.Element(ET.QName("uri", "tag"))
        self.serialize_check(elem, '<ns0:tag xmlns:ns0="uri" />') # 1.3
        elem = ET.Element(ET.QName("uri", "tag"))
        subelem = ET.SubElement(elem, ET.QName("uri", "tag1"))
        subelem = ET.SubElement(elem, ET.QName("uri", "tag2"))
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri"><ns0:tag1 /><ns0:tag2 /></ns0:tag>') # 1.4

        # 2) decorated attributes

        elem.clear()
        elem.attrib["{uri}key"] = "value"
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri" ns0:key="value" />') # 2.1

        elem.clear()
        elem.attrib[ET.QName("{uri}key")] = "value"
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri" ns0:key="value" />') # 2.2

        # 3) decorated values are not converted by default, but the
        # QName wrapper can be used for values

        elem.clear()
        elem.attrib["{uri}key"] = "{uri}value"
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri" ns0:key="{uri}value" />') # 3.1

        elem.clear()
        elem.attrib["{uri}key"] = ET.QName("{uri}value")
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri" ns0:key="ns0:value" />') # 3.2

        elem.clear()
        subelem = ET.Element("tag")
        subelem.attrib["{uri1}key"] = ET.QName("{uri2}value")
        elem.append(subelem)
        elem.append(subelem)
        self.serialize_check(elem,
            '<ns0:tag xmlns:ns0="uri" xmlns:ns1="uri1" xmlns:ns2="uri2">'
            '<tag ns1:key="ns2:value" />'
            '<tag ns1:key="ns2:value" />'
            '</ns0:tag>') # 3.3

        # 4) Direct QName tests

        self.assertEqual(str(ET.QName('ns', 'tag')), '{ns}tag')
        self.assertEqual(str(ET.QName('{ns}tag')), '{ns}tag')
        q1 = ET.QName('ns', 'tag')
        q2 = ET.QName('ns', 'tag')
        self.assertEqual(q1, q2)
        q2 = ET.QName('ns', 'other-tag')
        self.assertNotEqual(q1, q2)
        self.assertNotEqual(q1, 'ns:tag')
        self.assertEqual(q1, '{ns}tag')

    def test_doctype_public(self):
        # Test PUBLIC doctype.

        elem = ET.XML('<!DOCTYPE html PUBLIC'
                ' "-//W3C//DTD XHTML 1.0 Transitional//EN"'
                ' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">'
                '<html>text</html>')

    def test_xpath_tokenizer(self):
        # Test the XPath tokenizer.
        from xml.etree import ElementPath
        def check(p, expected):
            self.assertEqual([op or tag
                              for op, tag in ElementPath.xpath_tokenizer(p)],
                             expected)

        # tests from the xml specification
        check("*", ['*'])
        check("text()", ['text', '()'])
        check("@name", ['@', 'name'])
        check("@*", ['@', '*'])
        check("para[1]", ['para', '[', '1', ']'])
        check("para[last()]", ['para', '[', 'last', '()', ']'])
        check("*/para", ['*', '/', 'para'])
        check("/doc/chapter[5]/section[2]",
              ['/', 'doc', '/', 'chapter', '[', '5', ']',
               '/', 'section', '[', '2', ']'])
        check("chapter//para", ['chapter', '//', 'para'])
        check("//para", ['//', 'para'])
        check("//olist/item", ['//', 'olist', '/', 'item'])
        check(".", ['.'])
        check(".//para", ['.', '//', 'para'])
        check("..", ['..'])
        check("../@lang", ['..', '/', '@', 'lang'])
        check("chapter[title]", ['chapter', '[', 'title', ']'])
        check("employee[@secretary and @assistant]", ['employee',
              '[', '@', 'secretary', '', 'and', '', '@', 'assistant', ']'])

        # additional tests
        check("{http://spam}egg", ['{http://spam}egg'])
        check("./spam.egg", ['.', '/', 'spam.egg'])
        check(".//{http://spam}egg", ['.', '//', '{http://spam}egg'])

    def test_processinginstruction(self):
        # Test ProcessingInstruction directly

        self.assertEqual(ET.tostring(ET.ProcessingInstruction('test', 'instruction')),
                b'<?test instruction?>')
        self.assertEqual(ET.tostring(ET.PI('test', 'instruction')),
                b'<?test instruction?>')

        # Issue #2746

        self.assertEqual(ET.tostring(ET.PI('test', '<testing&>')),
                b'<?test <testing&>?>')
        self.assertEqual(ET.tostring(ET.PI('test', '<testing&>\xe3'), 'latin-1'),
                b"<?xml version='1.0' encoding='latin-1'?>\n"
                b"<?test <testing&>\xe3?>")

    def test_html_empty_elems_serialization(self):
        # issue 15970
        # from http://www.w3.org/TR/html401/index/elements.html
        for element in ['AREA', 'BASE', 'BASEFONT', 'BR', 'COL', 'FRAME', 'HR',
                        'IMG', 'INPUT', 'ISINDEX', 'LINK', 'META', 'PARAM']:
            for elem in [element, element.lower()]:
                expected = '<%s>' % elem
                serialized = serialize(ET.XML('<%s />' % elem), method='html')
                self.assertEqual(serialized, expected)
                serialized = serialize(ET.XML('<%s></%s>' % (elem,elem)),
                                       method='html')
                self.assertEqual(serialized, expected)


class XMLPullParserTest(unittest.TestCase):

    def _feed(self, parser, data, chunk_size=None):
        if chunk_size is None:
            parser.feed(data)
        else:
            for i in range(0, len(data), chunk_size):
                parser.feed(data[i:i+chunk_size])

    def assert_event_tags(self, parser, expected):
        events = parser.read_events()
        self.assertEqual([(action, elem.tag) for action, elem in events],
                         expected)

    def test_simple_xml(self):
        for chunk_size in (None, 1, 5):
            with self.subTest(chunk_size=chunk_size):
                parser = ET.XMLPullParser()
                self.assert_event_tags(parser, [])
                self._feed(parser, "<!-- comment -->\n", chunk_size)
                self.assert_event_tags(parser, [])
                self._feed(parser,
                           "<root>\n  <element key='value'>text</element",
                           chunk_size)
                self.assert_event_tags(parser, [])
                self._feed(parser, ">\n", chunk_size)
                self.assert_event_tags(parser, [('end', 'element')])
                self._feed(parser, "<element>text</element>tail\n", chunk_size)
                self._feed(parser, "<empty-element/>\n", chunk_size)
                self.assert_event_tags(parser, [
                    ('end', 'element'),
                    ('end', 'empty-element'),
                    ])
                self._feed(parser, "</root>\n", chunk_size)
                self.assert_event_tags(parser, [('end', 'root')])
                self.assertIsNone(parser.close())

    def test_feed_while_iterating(self):
        parser = ET.XMLPullParser()
        it = parser.read_events()
        self._feed(parser, "<root>\n  <element key='value'>text</element>\n")
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'element'))
        self._feed(parser, "</root>\n")
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'root'))
        with self.assertRaises(StopIteration):
            next(it)

    def test_simple_xml_with_ns(self):
        parser = ET.XMLPullParser()
        self.assert_event_tags(parser, [])
        self._feed(parser, "<!-- comment -->\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<root xmlns='namespace'>\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [('end', '{namespace}element')])
        self._feed(parser, "<element>text</element>tail\n")
        self._feed(parser, "<empty-element/>\n")
        self.assert_event_tags(parser, [
            ('end', '{namespace}element'),
            ('end', '{namespace}empty-element'),
            ])
        self._feed(parser, "</root>\n")
        self.assert_event_tags(parser, [('end', '{namespace}root')])
        self.assertIsNone(parser.close())

    def test_ns_events(self):
        parser = ET.XMLPullParser(events=('start-ns', 'end-ns'))
        self._feed(parser, "<!-- comment -->\n")
        self._feed(parser, "<root xmlns='namespace'>\n")
        self.assertEqual(
            list(parser.read_events()),
            [('start-ns', ('', 'namespace'))])
        self._feed(parser, "<element key='value'>text</element")
        self._feed(parser, ">\n")
        self._feed(parser, "<element>text</element>tail\n")
        self._feed(parser, "<empty-element/>\n")
        self._feed(parser, "</root>\n")
        self.assertEqual(list(parser.read_events()), [('end-ns', None)])
        self.assertIsNone(parser.close())

    def test_events(self):
        parser = ET.XMLPullParser(events=())
        self._feed(parser, "<root/>\n")
        self.assert_event_tags(parser, [])

        parser = ET.XMLPullParser(events=('start', 'end'))
        self._feed(parser, "<!-- comment -->\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<root>\n")
        self.assert_event_tags(parser, [('start', 'root')])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [('start', 'element')])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [('end', 'element')])
        self._feed(parser,
                   "<element xmlns='foo'>text<empty-element/></element>tail\n")
        self.assert_event_tags(parser, [
            ('start', '{foo}element'),
            ('start', '{foo}empty-element'),
            ('end', '{foo}empty-element'),
            ('end', '{foo}element'),
            ])
        self._feed(parser, "</root>")
        self.assertIsNone(parser.close())
        self.assert_event_tags(parser, [('end', 'root')])

        parser = ET.XMLPullParser(events=('start',))
        self._feed(parser, "<!-- comment -->\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<root>\n")
        self.assert_event_tags(parser, [('start', 'root')])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [('start', 'element')])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [])
        self._feed(parser,
                   "<element xmlns='foo'>text<empty-element/></element>tail\n")
        self.assert_event_tags(parser, [
            ('start', '{foo}element'),
            ('start', '{foo}empty-element'),
            ])
        self._feed(parser, "</root>")
        self.assertIsNone(parser.close())

    def test_events_sequence(self):
        # Test that events can be some sequence that's not just a tuple or list
        eventset = {'end', 'start'}
        parser = ET.XMLPullParser(events=eventset)
        self._feed(parser, "<foo>bar</foo>")
        self.assert_event_tags(parser, [('start', 'foo'), ('end', 'foo')])

        class DummyIter:
            def __init__(self):
                self.events = iter(['start', 'end', 'start-ns'])
            def __iter__(self):
                return self
            def __next__(self):
                return next(self.events)

        parser = ET.XMLPullParser(events=DummyIter())
        self._feed(parser, "<foo>bar</foo>")
        self.assert_event_tags(parser, [('start', 'foo'), ('end', 'foo')])


    def test_unknown_event(self):
        with self.assertRaises(ValueError):
            ET.XMLPullParser(events=('start', 'end', 'bogus'))


#
# xinclude tests (samples from appendix C of the xinclude specification)

XINCLUDE = {}

XINCLUDE["C1.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>120 Mz is adequate for an average home user.</p>
  <xi:include href="disclaimer.xml"/>
</document>
"""

XINCLUDE["disclaimer.xml"] = """\
<?xml version='1.0'?>
<disclaimer>
  <p>The opinions represented herein represent those of the individual
  and should not be interpreted as official policy endorsed by this
  organization.</p>
</disclaimer>
"""

XINCLUDE["C2.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>This document has been accessed
  <xi:include href="count.txt" parse="text"/> times.</p>
</document>
"""

XINCLUDE["count.txt"] = "324387"

XINCLUDE["C2b.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>This document has been <em>accessed</em>
  <xi:include href="count.txt" parse="text"/> times.</p>
</document>
"""

XINCLUDE["C3.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>The following is the source of the "data.xml" resource:</p>
  <example><xi:include href="data.xml" parse="text"/></example>
</document>
"""

XINCLUDE["data.xml"] = """\
<?xml version='1.0'?>
<data>
  <item><![CDATA[Brooks & Shields]]></item>
</data>
"""

XINCLUDE["C5.xml"] = """\
<?xml version='1.0'?>
<div xmlns:xi="http://www.w3.org/2001/XInclude">
  <xi:include href="example.txt" parse="text">
    <xi:fallback>
      <xi:include href="fallback-example.txt" parse="text">
        <xi:fallback><a href="mailto:bob@example.org">Report error</a></xi:fallback>
      </xi:include>
    </xi:fallback>
  </xi:include>
</div>
"""

XINCLUDE["default.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>Example.</p>
  <xi:include href="{}"/>
</document>
""".format(html.escape(SIMPLE_XMLFILE, True))

#
# badly formatted xi:include tags

XINCLUDE_BAD = {}

XINCLUDE_BAD["B1.xml"] = """\
<?xml version='1.0'?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <p>120 Mz is adequate for an average home user.</p>
  <xi:include href="disclaimer.xml" parse="BAD_TYPE"/>
</document>
"""

XINCLUDE_BAD["B2.xml"] = """\
<?xml version='1.0'?>
<div xmlns:xi="http://www.w3.org/2001/XInclude">
    <xi:fallback></xi:fallback>
</div>
"""

class XIncludeTest(unittest.TestCase):

    def xinclude_loader(self, href, parse="xml", encoding=None):
        try:
            data = XINCLUDE[href]
        except KeyError:
            raise OSError("resource not found")
        if parse == "xml":
            data = ET.XML(data)
        return data

    def none_loader(self, href, parser, encoding=None):
        return None

    def _my_loader(self, href, parse):
        # Used to avoid a test-dependency problem where the default loader
        # of ElementInclude uses the pyET parser for cET tests.
        if parse == 'xml':
            with open(href, 'rb') as f:
                return ET.parse(f).getroot()
        else:
            return None

    def test_xinclude_default(self):
        from xml.etree import ElementInclude
        doc = self.xinclude_loader('default.xml')
        ElementInclude.include(doc, self._my_loader)
        self.assertEqual(serialize(doc),
            '<document>\n'
            '  <p>Example.</p>\n'
            '  <root>\n'
            '   <element key="value">text</element>\n'
            '   <element>text</element>tail\n'
            '   <empty-element />\n'
            '</root>\n'
            '</document>')

    def test_xinclude(self):
        from xml.etree import ElementInclude

        # Basic inclusion example (XInclude C.1)
        document = self.xinclude_loader("C1.xml")
        ElementInclude.include(document, self.xinclude_loader)
        self.assertEqual(serialize(document),
            '<document>\n'
            '  <p>120 Mz is adequate for an average home user.</p>\n'
            '  <disclaimer>\n'
            '  <p>The opinions represented herein represent those of the individual\n'
            '  and should not be interpreted as official policy endorsed by this\n'
            '  organization.</p>\n'
            '</disclaimer>\n'
            '</document>') # C1

        # Textual inclusion example (XInclude C.2)
        document = self.xinclude_loader("C2.xml")
        ElementInclude.include(document, self.xinclude_loader)
        self.assertEqual(serialize(document),
            '<document>\n'
            '  <p>This document has been accessed\n'
            '  324387 times.</p>\n'
            '</document>') # C2

        # Textual inclusion after sibling element (based on modified XInclude C.2)
        document = self.xinclude_loader("C2b.xml")
        ElementInclude.include(document, self.xinclude_loader)
        self.assertEqual(serialize(document),
            '<document>\n'
            '  <p>This document has been <em>accessed</em>\n'
            '  324387 times.</p>\n'
            '</document>') # C2b

        # Textual inclusion of XML example (XInclude C.3)
        document = self.xinclude_loader("C3.xml")
        ElementInclude.include(document, self.xinclude_loader)
        self.assertEqual(serialize(document),
            '<document>\n'
            '  <p>The following is the source of the "data.xml" resource:</p>\n'
            "  <example>&lt;?xml version='1.0'?&gt;\n"
            '&lt;data&gt;\n'
            '  &lt;item&gt;&lt;![CDATA[Brooks &amp; Shields]]&gt;&lt;/item&gt;\n'
            '&lt;/data&gt;\n'
            '</example>\n'
            '</document>') # C3

        # Fallback example (XInclude C.5)
        # Note! Fallback support is not yet implemented
        document = self.xinclude_loader("C5.xml")
        with self.assertRaises(OSError) as cm:
            ElementInclude.include(document, self.xinclude_loader)
        self.assertEqual(str(cm.exception), 'resource not found')
        self.assertEqual(serialize(document),
            '<div xmlns:ns0="http://www.w3.org/2001/XInclude">\n'
            '  <ns0:include href="example.txt" parse="text">\n'
            '    <ns0:fallback>\n'
            '      <ns0:include href="fallback-example.txt" parse="text">\n'
            '        <ns0:fallback><a href="mailto:bob@example.org">Report error</a></ns0:fallback>\n'
            '      </ns0:include>\n'
            '    </ns0:fallback>\n'
            '  </ns0:include>\n'
            '</div>') # C5

    def test_xinclude_failures(self):
        from xml.etree import ElementInclude

        # Test failure to locate included XML file.
        document = ET.XML(XINCLUDE["C1.xml"])
        with self.assertRaises(ElementInclude.FatalIncludeError) as cm:
            ElementInclude.include(document, loader=self.none_loader)
        self.assertEqual(str(cm.exception),
                "cannot load 'disclaimer.xml' as 'xml'")

        # Test failure to locate included text file.
        document = ET.XML(XINCLUDE["C2.xml"])
        with self.assertRaises(ElementInclude.FatalIncludeError) as cm:
            ElementInclude.include(document, loader=self.none_loader)
        self.assertEqual(str(cm.exception),
                "cannot load 'count.txt' as 'text'")

        # Test bad parse type.
        document = ET.XML(XINCLUDE_BAD["B1.xml"])
        with self.assertRaises(ElementInclude.FatalIncludeError) as cm:
            ElementInclude.include(document, loader=self.none_loader)
        self.assertEqual(str(cm.exception),
                "unknown parse type in xi:include tag ('BAD_TYPE')")

        # Test xi:fallback outside xi:include.
        document = ET.XML(XINCLUDE_BAD["B2.xml"])
        with self.assertRaises(ElementInclude.FatalIncludeError) as cm:
            ElementInclude.include(document, loader=self.none_loader)
        self.assertEqual(str(cm.exception),
                "xi:fallback tag must be child of xi:include "
                "('{http://www.w3.org/2001/XInclude}fallback')")

# --------------------------------------------------------------------
# reported bugs

class BugsTest(unittest.TestCase):

    def test_bug_xmltoolkit21(self):
        # marshaller gives obscure errors for non-string values

        def check(elem):
            with self.assertRaises(TypeError) as cm:
                serialize(elem)
            self.assertEqual(str(cm.exception),
                    'cannot serialize 123 (type int)')

        elem = ET.Element(123)
        check(elem) # tag

        elem = ET.Element("elem")
        elem.text = 123
        check(elem) # text

        elem = ET.Element("elem")
        elem.tail = 123
        check(elem) # tail

        elem = ET.Element("elem")
        elem.set(123, "123")
        check(elem) # attribute key

        elem = ET.Element("elem")
        elem.set("123", 123)
        check(elem) # attribute value

    def test_bug_xmltoolkit25(self):
        # typo in ElementTree.findtext

        elem = ET.XML(SAMPLE_XML)
        tree = ET.ElementTree(elem)
        self.assertEqual(tree.findtext("tag"), 'text')
        self.assertEqual(tree.findtext("section/tag"), 'subtext')

    def test_bug_xmltoolkit28(self):
        # .//tag causes exceptions

        tree = ET.XML("<doc><table><tbody/></table></doc>")
        self.assertEqual(summarize_list(tree.findall(".//thead")), [])
        self.assertEqual(summarize_list(tree.findall(".//tbody")), ['tbody'])

    def test_bug_xmltoolkitX1(self):
        # dump() doesn't flush the output buffer

        tree = ET.XML("<doc><table><tbody/></table></doc>")
        with support.captured_stdout() as stdout:
            ET.dump(tree)
            self.assertEqual(stdout.getvalue(), '<doc><table><tbody /></table></doc>\n')

    def test_bug_xmltoolkit39(self):
        # non-ascii element and attribute names doesn't work

        tree = ET.XML(b"<?xml version='1.0' encoding='iso-8859-1'?><t\xe4g />")
        self.assertEqual(ET.tostring(tree, "utf-8"), b'<t\xc3\xa4g />')

        tree = ET.XML(b"<?xml version='1.0' encoding='iso-8859-1'?>"
                      b"<tag \xe4ttr='v&#228;lue' />")
        self.assertEqual(tree.attrib, {'\xe4ttr': 'v\xe4lue'})
        self.assertEqual(ET.tostring(tree, "utf-8"),
                b'<tag \xc3\xa4ttr="v\xc3\xa4lue" />')

        tree = ET.XML(b"<?xml version='1.0' encoding='iso-8859-1'?>"
                      b'<t\xe4g>text</t\xe4g>')
        self.assertEqual(ET.tostring(tree, "utf-8"),
                b'<t\xc3\xa4g>text</t\xc3\xa4g>')

        tree = ET.Element("t\u00e4g")
        self.assertEqual(ET.tostring(tree, "utf-8"), b'<t\xc3\xa4g />')

        tree = ET.Element("tag")
        tree.set("\u00e4ttr", "v\u00e4lue")
        self.assertEqual(ET.tostring(tree, "utf-8"),
                b'<tag \xc3\xa4ttr="v\xc3\xa4lue" />')

    def test_bug_xmltoolkit54(self):
        # problems handling internally defined entities

        e = ET.XML("<!DOCTYPE doc [<!ENTITY ldots '&#x8230;'>]>"
                   '<doc>&ldots;</doc>')
        self.assertEqual(serialize(e, encoding="us-ascii"),
                b'<doc>&#33328;</doc>')
        self.assertEqual(serialize(e), '<doc>\u8230</doc>')

    def test_bug_xmltoolkit55(self):
        # make sure we're reporting the first error, not the last

        with self.assertRaises(ET.ParseError) as cm:
            ET.XML(b"<!DOCTYPE doc SYSTEM 'doc.dtd'>"
                   b'<doc>&ldots;&ndots;&rdots;</doc>')
        self.assertEqual(str(cm.exception),
                'undefined entity &ldots;: line 1, column 36')

    def test_bug_xmltoolkit60(self):
        # Handle crash in stream source.

        class ExceptionFile:
            def read(self, x):
                raise OSError

        self.assertRaises(OSError, ET.parse, ExceptionFile())

    def test_bug_xmltoolkit62(self):
        # Don't crash when using custom entities.

        ENTITIES = {'rsquo': '\u2019', 'lsquo': '\u2018'}
        parser = ET.XMLParser()
        parser.entity.update(ENTITIES)
        parser.feed("""<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE patent-application-publication SYSTEM "pap-v15-2001-01-31.dtd" []>
<patent-application-publication>
<subdoc-abstract>
<paragraph id="A-0001" lvl="0">A new cultivar of Begonia plant named &lsquo;BCT9801BEG&rsquo;.</paragraph>
</subdoc-abstract>
</patent-application-publication>""")
        t = parser.close()
        self.assertEqual(t.find('.//paragraph').text,
            'A new cultivar of Begonia plant named \u2018BCT9801BEG\u2019.')

    @unittest.skipIf(sys.gettrace(), "Skips under coverage.")
    def test_bug_xmltoolkit63(self):
        # Check reference leak.
        def xmltoolkit63():
            tree = ET.TreeBuilder()
            tree.start("tag", {})
            tree.data("text")
            tree.end("tag")

        xmltoolkit63()
        count = sys.getrefcount(None)
        for i in range(1000):
            xmltoolkit63()
        self.assertEqual(sys.getrefcount(None), count)

    def test_bug_200708_newline(self):
        # Preserve newlines in attributes.

        e = ET.Element('SomeTag', text="def _f():\n  return 3\n")
        self.assertEqual(ET.tostring(e),
                b'<SomeTag text="def _f():&#10;  return 3&#10;" />')
        self.assertEqual(ET.XML(ET.tostring(e)).get("text"),
                'def _f():\n  return 3\n')
        self.assertEqual(ET.tostring(ET.XML(ET.tostring(e))),
                b'<SomeTag text="def _f():&#10;  return 3&#10;" />')

    def test_bug_200708_close(self):
        # Test default builder.
        parser = ET.XMLParser() # default
        parser.feed("<element>some text</element>")
        self.assertEqual(parser.close().tag, 'element')

        # Test custom builder.
        class EchoTarget:
            def close(self):
                return ET.Element("element") # simulate root
        parser = ET.XMLParser(EchoTarget())
        parser.feed("<element>some text</element>")
        self.assertEqual(parser.close().tag, 'element')

    def test_bug_200709_default_namespace(self):
        e = ET.Element("{default}elem")
        s = ET.SubElement(e, "{default}elem")
        self.assertEqual(serialize(e, default_namespace="default"), # 1
                '<elem xmlns="default"><elem /></elem>')

        e = ET.Element("{default}elem")
        s = ET.SubElement(e, "{default}elem")
        s = ET.SubElement(e, "{not-default}elem")
        self.assertEqual(serialize(e, default_namespace="default"), # 2
            '<elem xmlns="default" xmlns:ns1="not-default">'
            '<elem />'
            '<ns1:elem />'
            '</elem>')

        e = ET.Element("{default}elem")
        s = ET.SubElement(e, "{default}elem")
        s = ET.SubElement(e, "elem") # unprefixed name
        with self.assertRaises(ValueError) as cm:
            serialize(e, default_namespace="default") # 3
        self.assertEqual(str(cm.exception),
                'cannot use non-qualified names with default_namespace option')

    def test_bug_200709_register_namespace(self):
        e = ET.Element("{http://namespace.invalid/does/not/exist/}title")
        self.assertEqual(ET.tostring(e),
            b'<ns0:title xmlns:ns0="http://namespace.invalid/does/not/exist/" />')
        ET.register_namespace("foo", "http://namespace.invalid/does/not/exist/")
        e = ET.Element("{http://namespace.invalid/does/not/exist/}title")
        self.assertEqual(ET.tostring(e),
            b'<foo:title xmlns:foo="http://namespace.invalid/does/not/exist/" />')

        # And the Dublin Core namespace is in the default list:

        e = ET.Element("{http://purl.org/dc/elements/1.1/}title")
        self.assertEqual(ET.tostring(e),
            b'<dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" />')

    def test_bug_200709_element_comment(self):
        # Not sure if this can be fixed, really (since the serializer needs
        # ET.Comment, not cET.comment).

        a = ET.Element('a')
        a.append(ET.Comment('foo'))
        self.assertEqual(a[0].tag, ET.Comment)

        a = ET.Element('a')
        a.append(ET.PI('foo'))
        self.assertEqual(a[0].tag, ET.PI)

    def test_bug_200709_element_insert(self):
        a = ET.Element('a')
        b = ET.SubElement(a, 'b')
        c = ET.SubElement(a, 'c')
        d = ET.Element('d')
        a.insert(0, d)
        self.assertEqual(summarize_list(a), ['d', 'b', 'c'])
        a.insert(-1, d)
        self.assertEqual(summarize_list(a), ['d', 'b', 'd', 'c'])

    def test_bug_200709_iter_comment(self):
        a = ET.Element('a')
        b = ET.SubElement(a, 'b')
        comment_b = ET.Comment("TEST-b")
        b.append(comment_b)
        self.assertEqual(summarize_list(a.iter(ET.Comment)), [ET.Comment])

    # --------------------------------------------------------------------
    # reported on bugs.python.org

    def test_bug_1534630(self):
        bob = ET.TreeBuilder()
        e = bob.data("data")
        e = bob.start("tag", {})
        e = bob.end("tag")
        e = bob.close()
        self.assertEqual(serialize(e), '<tag />')

    def test_issue6233(self):
        e = ET.XML(b"<?xml version='1.0' encoding='utf-8'?>"
                   b'<body>t\xc3\xa3g</body>')
        self.assertEqual(ET.tostring(e, 'ascii'),
                b"<?xml version='1.0' encoding='ascii'?>\n"
                b'<body>t&#227;g</body>')
        e = ET.XML(b"<?xml version='1.0' encoding='iso-8859-1'?>"
                   b'<body>t\xe3g</body>')
        self.assertEqual(ET.tostring(e, 'ascii'),
                b"<?xml version='1.0' encoding='ascii'?>\n"
                b'<body>t&#227;g</body>')

    def test_issue3151(self):
        e = ET.XML('<prefix:localname xmlns:prefix="${stuff}"/>')
        self.assertEqual(e.tag, '{${stuff}}localname')
        t = ET.ElementTree(e)
        self.assertEqual(ET.tostring(e), b'<ns0:localname xmlns:ns0="${stuff}" />')

    def test_issue6565(self):
        elem = ET.XML("<body><tag/></body>")
        self.assertEqual(summarize_list(elem), ['tag'])
        newelem = ET.XML(SAMPLE_XML)
        elem[:] = newelem[:]
        self.assertEqual(summarize_list(elem), ['tag', 'tag', 'section'])

    def test_issue10777(self):
        # Registering a namespace twice caused a "dictionary changed size during
        # iteration" bug.

        ET.register_namespace('test10777', 'http://myuri/')
        ET.register_namespace('test10777', 'http://myuri/')

    def test_lost_text(self):
        # Issue #25902: Borrowed text can disappear
        class Text:
            def __bool__(self):
                e.text = 'changed'
                return True

        e = ET.Element('tag')
        e.text = Text()
        i = e.itertext()
        t = next(i)
        self.assertIsInstance(t, Text)
        self.assertIsInstance(e.text, str)
        self.assertEqual(e.text, 'changed')

    def test_lost_tail(self):
        # Issue #25902: Borrowed tail can disappear
        class Text:
            def __bool__(self):
                e[0].tail = 'changed'
                return True

        e = ET.Element('root')
        e.append(ET.Element('tag'))
        e[0].tail = Text()
        i = e.itertext()
        t = next(i)
        self.assertIsInstance(t, Text)
        self.assertIsInstance(e[0].tail, str)
        self.assertEqual(e[0].tail, 'changed')

    def test_lost_elem(self):
        # Issue #25902: Borrowed element can disappear
        class Tag:
            def __eq__(self, other):
                e[0] = ET.Element('changed')
                next(i)
                return True

        e = ET.Element('root')
        e.append(ET.Element(Tag()))
        e.append(ET.Element('tag'))
        i = e.iter('tag')
        try:
            t = next(i)
        except ValueError:
            self.skipTest('generators are not reentrant')
        self.assertIsInstance(t.tag, Tag)
        self.assertIsInstance(e[0].tag, str)
        self.assertEqual(e[0].tag, 'changed')

    def check_expat224_utf8_bug(self, text):
        xml = b'<a b="%s"/>' % text
        root = ET.XML(xml)
        self.assertEqual(root.get('b'), text.decode('utf-8'))

    def test_expat224_utf8_bug(self):
        # bpo-31170: Expat 2.2.3 had a bug in its UTF-8 decoder.
        # Check that Expat 2.2.4 fixed the bug.
        #
        # Test buffer bounds at odd and even positions.

        text = b'\xc3\xa0' * 1024
        self.check_expat224_utf8_bug(text)

        text = b'x' + b'\xc3\xa0' * 1024
        self.check_expat224_utf8_bug(text)

    def test_expat224_utf8_bug_file(self):
        with open(UTF8_BUG_XMLFILE, 'rb') as fp:
            raw = fp.read()
        root = ET.fromstring(raw)
        xmlattr = root.get('b')

        # "Parse" manually the XML file to extract the value of the 'b'
        # attribute of the <a b='xxx' /> XML element
        text = raw.decode('utf-8').strip()
        text = text.replace('\r\n', ' ')
        text = text[6:-4]
        self.assertEqual(root.get('b'), text)



# --------------------------------------------------------------------


class BasicElementTest(ElementTestCase, unittest.TestCase):
    def test_augmentation_type_errors(self):
        e = ET.Element('joe')
        self.assertRaises(TypeError, e.append, 'b')
        self.assertRaises(TypeError, e.extend, [ET.Element('bar'), 'foo'])
        self.assertRaises(TypeError, e.insert, 0, 'foo')

    def test_cyclic_gc(self):
        class Dummy:
            pass

        # Test the shortest cycle: d->element->d
        d = Dummy()
        d.dummyref = ET.Element('joe', attr=d)
        wref = weakref.ref(d)
        del d
        gc_collect()
        self.assertIsNone(wref())

        # A longer cycle: d->e->e2->d
        e = ET.Element('joe')
        d = Dummy()
        d.dummyref = e
        wref = weakref.ref(d)
        e2 = ET.SubElement(e, 'foo', attr=d)
        del d, e, e2
        gc_collect()
        self.assertIsNone(wref())

        # A cycle between Element objects as children of one another
        # e1->e2->e3->e1
        e1 = ET.Element('e1')
        e2 = ET.Element('e2')
        e3 = ET.Element('e3')
        e1.append(e2)
        e2.append(e2)
        e3.append(e1)
        wref = weakref.ref(e1)
        del e1, e2, e3
        gc_collect()
        self.assertIsNone(wref())

    def test_weakref(self):
        flag = False
        def wref_cb(w):
            nonlocal flag
            flag = True
        e = ET.Element('e')
        wref = weakref.ref(e, wref_cb)
        self.assertEqual(wref().tag, 'e')
        del e
        self.assertEqual(flag, True)
        self.assertEqual(wref(), None)

    def test_get_keyword_args(self):
        e1 = ET.Element('foo' , x=1, y=2, z=3)
        self.assertEqual(e1.get('x', default=7), 1)
        self.assertEqual(e1.get('w', default=7), 7)

    def test_pickle(self):
        # issue #16076: the C implementation wasn't pickleable.
        for proto in range(2, pickle.HIGHEST_PROTOCOL + 1):
            for dumper, loader in product(self.modules, repeat=2):
                e = dumper.Element('foo', bar=42)
                e.text = "text goes here"
                e.tail = "opposite of head"
                dumper.SubElement(e, 'child').append(dumper.Element('grandchild'))
                e.append(dumper.Element('child'))
                e.findall('.//grandchild')[0].set('attr', 'other value')

                e2 = self.pickleRoundTrip(e, 'xml.etree.ElementTree',
                                          dumper, loader, proto)

                self.assertEqual(e2.tag, 'foo')
                self.assertEqual(e2.attrib['bar'], 42)
                self.assertEqual(len(e2), 2)
                self.assertEqualElements(e, e2)

    def test_pickle_issue18997(self):
        for proto in range(2, pickle.HIGHEST_PROTOCOL + 1):
            for dumper, loader in product(self.modules, repeat=2):
                XMLTEXT = """<?xml version="1.0"?>
                    <group><dogs>4</dogs>
                    </group>"""
                e1 = dumper.fromstring(XMLTEXT)
                if hasattr(e1, '__getstate__'):
                    self.assertEqual(e1.__getstate__()['tag'], 'group')
                e2 = self.pickleRoundTrip(e1, 'xml.etree.ElementTree',
                                          dumper, loader, proto)
                self.assertEqual(e2.tag, 'group')
                self.assertEqual(e2[0].tag, 'dogs')


class BadElementTest(ElementTestCase, unittest.TestCase):
    def test_extend_mutable_list(self):
        class X:
            @property
            def __class__(self):
                L[:] = [ET.Element('baz')]
                return ET.Element
        L = [X()]
        e = ET.Element('foo')
        try:
            e.extend(L)
        except TypeError:
            pass

        class Y(X, ET.Element):
            pass
        L = [Y('x')]
        e = ET.Element('foo')
        e.extend(L)

    def test_extend_mutable_list2(self):
        class X:
            @property
            def __class__(self):
                del L[:]
                return ET.Element
        L = [X(), ET.Element('baz')]
        e = ET.Element('foo')
        try:
            e.extend(L)
        except TypeError:
            pass

        class Y(X, ET.Element):
            pass
        L = [Y('bar'), ET.Element('baz')]
        e = ET.Element('foo')
        e.extend(L)

    def test_remove_with_mutating(self):
        class X(ET.Element):
            def __eq__(self, o):
                del e[:]
                return False
        e = ET.Element('foo')
        e.extend([X('bar')])
        self.assertRaises(ValueError, e.remove, ET.Element('baz'))

        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        self.assertRaises(ValueError, e.remove, X('baz'))

    def test_recursive_repr(self):
        # Issue #25455
        e = ET.Element('foo')
        with swap_attr(e, 'tag', e):
            with self.assertRaises(RuntimeError):
                repr(e)  # Should not crash

    def test_element_get_text(self):
        # Issue #27863
        class X(str):
            def __del__(self):
                try:
                    elem.text
                except NameError:
                    pass

        b = ET.TreeBuilder()
        b.start('tag', {})
        b.data('ABCD')
        b.data(X('EFGH'))
        b.data('IJKL')
        b.end('tag')

        elem = b.close()
        self.assertEqual(elem.text, 'ABCDEFGHIJKL')

    def test_element_get_tail(self):
        # Issue #27863
        class X(str):
            def __del__(self):
                try:
                    elem[0].tail
                except NameError:
                    pass

        b = ET.TreeBuilder()
        b.start('root', {})
        b.start('tag', {})
        b.end('tag')
        b.data('ABCD')
        b.data(X('EFGH'))
        b.data('IJKL')
        b.end('root')

        elem = b.close()
        self.assertEqual(elem[0].tail, 'ABCDEFGHIJKL')

    def test_element_iter(self):
        # Issue #27863
        state = {
            'tag': 'tag',
            '_children': [None],  # non-Element
            'attrib': 'attr',
            'tail': 'tail',
            'text': 'text',
        }

        e = ET.Element('tag')
        try:
            e.__setstate__(state)
        except AttributeError:
            e.__dict__ = state

        it = e.iter()
        self.assertIs(next(it), e)
        self.assertRaises(AttributeError, next, it)

    def test_subscr(self):
        # Issue #27863
        class X:
            def __index__(self):
                del e[:]
                return 1

        e = ET.Element('elem')
        e.append(ET.Element('child'))
        e[:X()]  # shouldn't crash

        e.append(ET.Element('child'))
        e[0:10:X()]  # shouldn't crash

    def test_ass_subscr(self):
        # Issue #27863
        class X:
            def __index__(self):
                e[:] = []
                return 1

        e = ET.Element('elem')
        for _ in range(10):
            e.insert(0, ET.Element('child'))

        e[0:10:X()] = []  # shouldn't crash

    def test_treebuilder_start(self):
        # Issue #27863
        def element_factory(x, y):
            return []
        b = ET.TreeBuilder(element_factory=element_factory)

        b.start('tag', {})
        b.data('ABCD')
        self.assertRaises(AttributeError, b.start, 'tag2', {})
        del b
        gc_collect()

    def test_treebuilder_end(self):
        # Issue #27863
        def element_factory(x, y):
            return []
        b = ET.TreeBuilder(element_factory=element_factory)

        b.start('tag', {})
        b.data('ABCD')
        self.assertRaises(AttributeError, b.end, 'tag')
        del b
        gc_collect()


class MutatingElementPath(str):
    def __new__(cls, elem, *args):
        self = str.__new__(cls, *args)
        self.elem = elem
        return self
    def __eq__(self, o):
        del self.elem[:]
        return True
MutatingElementPath.__hash__ = str.__hash__

class BadElementPath(str):
    def __eq__(self, o):
        raise 1/0
BadElementPath.__hash__ = str.__hash__

class BadElementPathTest(ElementTestCase, unittest.TestCase):
    def setUp(self):
        super().setUp()
        from xml.etree import ElementPath
        self.path_cache = ElementPath._cache
        ElementPath._cache = {}

    def tearDown(self):
        from xml.etree import ElementPath
        ElementPath._cache = self.path_cache
        super().tearDown()

    def test_find_with_mutating(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        e.find(MutatingElementPath(e, 'x'))

    def test_find_with_error(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        try:
            e.find(BadElementPath('x'))
        except ZeroDivisionError:
            pass

    def test_findtext_with_mutating(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        e.findtext(MutatingElementPath(e, 'x'))

    def test_findtext_with_error(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        try:
            e.findtext(BadElementPath('x'))
        except ZeroDivisionError:
            pass

    def test_findall_with_mutating(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        e.findall(MutatingElementPath(e, 'x'))

    def test_findall_with_error(self):
        e = ET.Element('foo')
        e.extend([ET.Element('bar')])
        try:
            e.findall(BadElementPath('x'))
        except ZeroDivisionError:
            pass


class ElementTreeTypeTest(unittest.TestCase):
    def test_istype(self):
        self.assertIsInstance(ET.ParseError, type)
        self.assertIsInstance(ET.QName, type)
        self.assertIsInstance(ET.ElementTree, type)
        self.assertIsInstance(ET.Element, type)
        self.assertIsInstance(ET.TreeBuilder, type)
        self.assertIsInstance(ET.XMLParser, type)

    def test_Element_subclass_trivial(self):
        class MyElement(ET.Element):
            pass

        mye = MyElement('foo')
        self.assertIsInstance(mye, ET.Element)
        self.assertIsInstance(mye, MyElement)
        self.assertEqual(mye.tag, 'foo')

        # test that attribute assignment works (issue 14849)
        mye.text = "joe"
        self.assertEqual(mye.text, "joe")

    def test_Element_subclass_constructor(self):
        class MyElement(ET.Element):
            def __init__(self, tag, attrib={}, **extra):
                super(MyElement, self).__init__(tag + '__', attrib, **extra)

        mye = MyElement('foo', {'a': 1, 'b': 2}, c=3, d=4)
        self.assertEqual(mye.tag, 'foo__')
        self.assertEqual(sorted(mye.items()),
            [('a', 1), ('b', 2), ('c', 3), ('d', 4)])

    def test_Element_subclass_new_method(self):
        class MyElement(ET.Element):
            def newmethod(self):
                return self.tag

        mye = MyElement('joe')
        self.assertEqual(mye.newmethod(), 'joe')

    def test_Element_subclass_find(self):
        class MyElement(ET.Element):
            pass

        e = ET.Element('foo')
        e.text = 'text'
        sub = MyElement('bar')
        sub.text = 'subtext'
        e.append(sub)
        self.assertEqual(e.findtext('bar'), 'subtext')
        self.assertEqual(e.find('bar').tag, 'bar')
        found = list(e.findall('bar'))
        self.assertEqual(len(found), 1, found)
        self.assertEqual(found[0].tag, 'bar')


class ElementFindTest(unittest.TestCase):
    def test_find_simple(self):
        e = ET.XML(SAMPLE_XML)
        self.assertEqual(e.find('tag').tag, 'tag')
        self.assertEqual(e.find('section/tag').tag, 'tag')
        self.assertEqual(e.find('./tag').tag, 'tag')

        e[2] = ET.XML(SAMPLE_SECTION)
        self.assertEqual(e.find('section/nexttag').tag, 'nexttag')

        self.assertEqual(e.findtext('./tag'), 'text')
        self.assertEqual(e.findtext('section/tag'), 'subtext')

        # section/nexttag is found but has no text
        self.assertEqual(e.findtext('section/nexttag'), '')
        self.assertEqual(e.findtext('section/nexttag', 'default'), '')

        # tog doesn't exist and 'default' kicks in
        self.assertIsNone(e.findtext('tog'))
        self.assertEqual(e.findtext('tog', 'default'), 'default')

        # Issue #16922
        self.assertEqual(ET.XML('<tag><empty /></tag>').findtext('empty'), '')

    def test_find_xpath(self):
        LINEAR_XML = '''
        <body>
            <tag class='a'/>
            <tag class='b'/>
            <tag class='c'/>
            <tag class='d'/>
        </body>'''
        e = ET.XML(LINEAR_XML)

        # Test for numeric indexing and last()
        self.assertEqual(e.find('./tag[1]').attrib['class'], 'a')
        self.assertEqual(e.find('./tag[2]').attrib['class'], 'b')
        self.assertEqual(e.find('./tag[last()]').attrib['class'], 'd')
        self.assertEqual(e.find('./tag[last()-1]').attrib['class'], 'c')
        self.assertEqual(e.find('./tag[last()-2]').attrib['class'], 'b')

        self.assertRaisesRegex(SyntaxError, 'XPath', e.find, './tag[0]')
        self.assertRaisesRegex(SyntaxError, 'XPath', e.find, './tag[-1]')
        self.assertRaisesRegex(SyntaxError, 'XPath', e.find, './tag[last()-0]')
        self.assertRaisesRegex(SyntaxError, 'XPath', e.find, './tag[last()+1]')

    def test_findall(self):
        e = ET.XML(SAMPLE_XML)
        e[2] = ET.XML(SAMPLE_SECTION)
        self.assertEqual(summarize_list(e.findall('.')), ['body'])
        self.assertEqual(summarize_list(e.findall('tag')), ['tag', 'tag'])
        self.assertEqual(summarize_list(e.findall('tog')), [])
        self.assertEqual(summarize_list(e.findall('tog/foo')), [])
        self.assertEqual(summarize_list(e.findall('*')),
            ['tag', 'tag', 'section'])
        self.assertEqual(summarize_list(e.findall('.//tag')),
            ['tag'] * 4)
        self.assertEqual(summarize_list(e.findall('section/tag')), ['tag'])
        self.assertEqual(summarize_list(e.findall('section//tag')), ['tag'] * 2)
        self.assertEqual(summarize_list(e.findall('section/*')),
            ['tag', 'nexttag', 'nextsection'])
        self.assertEqual(summarize_list(e.findall('section//*')),
            ['tag', 'nexttag', 'nextsection', 'tag'])
        self.assertEqual(summarize_list(e.findall('section/.//*')),
            ['tag', 'nexttag', 'nextsection', 'tag'])
        self.assertEqual(summarize_list(e.findall('*/*')),
            ['tag', 'nexttag', 'nextsection'])
        self.assertEqual(summarize_list(e.findall('*//*')),
            ['tag', 'nexttag', 'nextsection', 'tag'])
        self.assertEqual(summarize_list(e.findall('*/tag')), ['tag'])
        self.assertEqual(summarize_list(e.findall('*/./tag')), ['tag'])
        self.assertEqual(summarize_list(e.findall('./tag')), ['tag'] * 2)
        self.assertEqual(summarize_list(e.findall('././tag')), ['tag'] * 2)

        self.assertEqual(summarize_list(e.findall('.//tag[@class]')),
            ['tag'] * 3)
        self.assertEqual(summarize_list(e.findall('.//tag[@class="a"]')),
            ['tag'])
        self.assertEqual(summarize_list(e.findall('.//tag[@class="b"]')),
            ['tag'] * 2)
        self.assertEqual(summarize_list(e.findall('.//tag[@id]')),
            ['tag'])
        self.assertEqual(summarize_list(e.findall('.//section[tag]')),
            ['section'])
        self.assertEqual(summarize_list(e.findall('.//section[element]')), [])
        self.assertEqual(summarize_list(e.findall('../tag')), [])
        self.assertEqual(summarize_list(e.findall('section/../tag')),
            ['tag'] * 2)
        self.assertEqual(e.findall('section//'), e.findall('section//*'))

    def test_test_find_with_ns(self):
        e = ET.XML(SAMPLE_XML_NS)
        self.assertEqual(summarize_list(e.findall('tag')), [])
        self.assertEqual(
            summarize_list(e.findall("{http://effbot.org/ns}tag")),
            ['{http://effbot.org/ns}tag'] * 2)
        self.assertEqual(
            summarize_list(e.findall(".//{http://effbot.org/ns}tag")),
            ['{http://effbot.org/ns}tag'] * 3)

    def test_findall_different_nsmaps(self):
        root = ET.XML('''
            <a xmlns:x="X" xmlns:y="Y">
                <x:b><c/></x:b>
                <b/>
                <c><x:b/><b/></c><y:b/>
            </a>''')
        nsmap = {'xx': 'X'}
        self.assertEqual(len(root.findall(".//xx:b", namespaces=nsmap)), 2)
        self.assertEqual(len(root.findall(".//b", namespaces=nsmap)), 2)
        nsmap = {'xx': 'Y'}
        self.assertEqual(len(root.findall(".//xx:b", namespaces=nsmap)), 1)
        self.assertEqual(len(root.findall(".//b", namespaces=nsmap)), 2)

    def test_bad_find(self):
        e = ET.XML(SAMPLE_XML)
        with self.assertRaisesRegex(SyntaxError, 'cannot use absolute path'):
            e.findall('/tag')

    def test_find_through_ElementTree(self):
        e = ET.XML(SAMPLE_XML)
        self.assertEqual(ET.ElementTree(e).find('tag').tag, 'tag')
        self.assertEqual(ET.ElementTree(e).findtext('tag'), 'text')
        self.assertEqual(summarize_list(ET.ElementTree(e).findall('tag')),
            ['tag'] * 2)
        # this produces a warning
        self.assertEqual(summarize_list(ET.ElementTree(e).findall('//tag')),
            ['tag'] * 3)


class ElementIterTest(unittest.TestCase):
    def _ilist(self, elem, tag=None):
        return summarize_list(elem.iter(tag))

    def test_basic(self):
        doc = ET.XML("<html><body>this is a <i>paragraph</i>.</body>..</html>")
        self.assertEqual(self._ilist(doc), ['html', 'body', 'i'])
        self.assertEqual(self._ilist(doc.find('body')), ['body', 'i'])
        self.assertEqual(next(doc.iter()).tag, 'html')
        self.assertEqual(''.join(doc.itertext()), 'this is a paragraph...')
        self.assertEqual(''.join(doc.find('body').itertext()),
            'this is a paragraph.')
        self.assertEqual(next(doc.itertext()), 'this is a ')

        # iterparse should return an iterator
        sourcefile = serialize(doc, to_string=False)
        self.assertEqual(next(ET.iterparse(sourcefile))[0], 'end')

        # With an explicit parser too (issue #9708)
        sourcefile = serialize(doc, to_string=False)
        parser = ET.XMLParser(target=ET.TreeBuilder())
        self.assertEqual(next(ET.iterparse(sourcefile, parser=parser))[0],
                         'end')

        tree = ET.ElementTree(None)
        self.assertRaises(AttributeError, tree.iter)

        # Issue #16913
        doc = ET.XML("<root>a&amp;<sub>b&amp;</sub>c&amp;</root>")
        self.assertEqual(''.join(doc.itertext()), 'a&b&c&')

    def test_corners(self):
        # single root, no subelements
        a = ET.Element('a')
        self.assertEqual(self._ilist(a), ['a'])

        # one child
        b = ET.SubElement(a, 'b')
        self.assertEqual(self._ilist(a), ['a', 'b'])

        # one child and one grandchild
        c = ET.SubElement(b, 'c')
        self.assertEqual(self._ilist(a), ['a', 'b', 'c'])

        # two children, only first with grandchild
        d = ET.SubElement(a, 'd')
        self.assertEqual(self._ilist(a), ['a', 'b', 'c', 'd'])

        # replace first child by second
        a[0] = a[1]
        del a[1]
        self.assertEqual(self._ilist(a), ['a', 'd'])

    def test_iter_by_tag(self):
        doc = ET.XML('''
            <document>
                <house>
                    <room>bedroom1</room>
                    <room>bedroom2</room>
                </house>
                <shed>nothing here
                </shed>
                <house>
                    <room>bedroom8</room>
                </house>
            </document>''')

        self.assertEqual(self._ilist(doc, 'room'), ['room'] * 3)
        self.assertEqual(self._ilist(doc, 'house'), ['house'] * 2)

        # test that iter also accepts 'tag' as a keyword arg
        self.assertEqual(
            summarize_list(doc.iter(tag='room')),
            ['room'] * 3)

        # make sure both tag=None and tag='*' return all tags
        all_tags = ['document', 'house', 'room', 'room',
                    'shed', 'house', 'room']
        self.assertEqual(summarize_list(doc.iter()), all_tags)
        self.assertEqual(self._ilist(doc), all_tags)
        self.assertEqual(self._ilist(doc, '*'), all_tags)

    def test_getiterator(self):
        doc = ET.XML('''
            <document>
                <house>
                    <room>bedroom1</room>
                    <room>bedroom2</room>
                </house>
                <shed>nothing here
                </shed>
                <house>
                    <room>bedroom8</room>
                </house>
            </document>''')

        self.assertEqual(summarize_list(doc.getiterator('room')),
                         ['room'] * 3)
        self.assertEqual(summarize_list(doc.getiterator('house')),
                         ['house'] * 2)

        # test that getiterator also accepts 'tag' as a keyword arg
        self.assertEqual(
            summarize_list(doc.getiterator(tag='room')),
            ['room'] * 3)

        # make sure both tag=None and tag='*' return all tags
        all_tags = ['document', 'house', 'room', 'room',
                    'shed', 'house', 'room']
        self.assertEqual(summarize_list(doc.getiterator()), all_tags)
        self.assertEqual(summarize_list(doc.getiterator(None)), all_tags)
        self.assertEqual(summarize_list(doc.getiterator('*')), all_tags)

    def test_copy(self):
        a = ET.Element('a')
        it = a.iter()
        with self.assertRaises(TypeError):
            copy.copy(it)

    def test_pickle(self):
        a = ET.Element('a')
        it = a.iter()
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            with self.assertRaises((TypeError, pickle.PicklingError)):
                pickle.dumps(it, proto)


class TreeBuilderTest(unittest.TestCase):
    sample1 = ('<!DOCTYPE html PUBLIC'
        ' "-//W3C//DTD XHTML 1.0 Transitional//EN"'
        ' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">'
        '<html>text<div>subtext</div>tail</html>')

    sample2 = '''<toplevel>sometext</toplevel>'''

    def _check_sample1_element(self, e):
        self.assertEqual(e.tag, 'html')
        self.assertEqual(e.text, 'text')
        self.assertEqual(e.tail, None)
        self.assertEqual(e.attrib, {})
        children = list(e)
        self.assertEqual(len(children), 1)
        child = children[0]
        self.assertEqual(child.tag, 'div')
        self.assertEqual(child.text, 'subtext')
        self.assertEqual(child.tail, 'tail')
        self.assertEqual(child.attrib, {})

    def test_dummy_builder(self):
        class BaseDummyBuilder:
            def close(self):
                return 42

        class DummyBuilder(BaseDummyBuilder):
            data = start = end = lambda *a: None

        parser = ET.XMLParser(target=DummyBuilder())
        parser.feed(self.sample1)
        self.assertEqual(parser.close(), 42)

        parser = ET.XMLParser(target=BaseDummyBuilder())
        parser.feed(self.sample1)
        self.assertEqual(parser.close(), 42)

        parser = ET.XMLParser(target=object())
        parser.feed(self.sample1)
        self.assertIsNone(parser.close())

    def test_treebuilder_elementfactory_none(self):
        parser = ET.XMLParser(target=ET.TreeBuilder(element_factory=None))
        parser.feed(self.sample1)
        e = parser.close()
        self._check_sample1_element(e)

    def test_subclass(self):
        class MyTreeBuilder(ET.TreeBuilder):
            def foobar(self, x):
                return x * 2

        tb = MyTreeBuilder()
        self.assertEqual(tb.foobar(10), 20)

        parser = ET.XMLParser(target=tb)
        parser.feed(self.sample1)

        e = parser.close()
        self._check_sample1_element(e)

    def test_element_factory(self):
        lst = []
        def myfactory(tag, attrib):
            nonlocal lst
            lst.append(tag)
            return ET.Element(tag, attrib)

        tb = ET.TreeBuilder(element_factory=myfactory)
        parser = ET.XMLParser(target=tb)
        parser.feed(self.sample2)
        parser.close()

        self.assertEqual(lst, ['toplevel'])

    def _check_element_factory_class(self, cls):
        tb = ET.TreeBuilder(element_factory=cls)

        parser = ET.XMLParser(target=tb)
        parser.feed(self.sample1)
        e = parser.close()
        self.assertIsInstance(e, cls)
        self._check_sample1_element(e)

    def test_element_factory_subclass(self):
        class MyElement(ET.Element):
            pass
        self._check_element_factory_class(MyElement)

    def test_element_factory_pure_python_subclass(self):
        # Mimick SimpleTAL's behaviour (issue #16089): both versions of
        # TreeBuilder should be able to cope with a subclass of the
        # pure Python Element class.
        base = ET._Element_Py
        # Not from a C extension
        self.assertEqual(base.__module__, 'xml.etree.ElementTree')
        # Force some multiple inheritance with a C class to make things
        # more interesting.
        class MyElement(base, ValueError):
            pass
        self._check_element_factory_class(MyElement)

    def test_doctype(self):
        class DoctypeParser:
            _doctype = None

            def doctype(self, name, pubid, system):
                self._doctype = (name, pubid, system)

            def close(self):
                return self._doctype

        parser = ET.XMLParser(target=DoctypeParser())
        parser.feed(self.sample1)

        self.assertEqual(parser.close(),
            ('html', '-//W3C//DTD XHTML 1.0 Transitional//EN',
             'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'))

    def test_builder_lookup_errors(self):
        class RaisingBuilder:
            def __init__(self, raise_in=None, what=ValueError):
                self.raise_in = raise_in
                self.what = what

            def __getattr__(self, name):
                if name == self.raise_in:
                    raise self.what(self.raise_in)
                def handle(*args):
                    pass
                return handle

        ET.XMLParser(target=RaisingBuilder())
        # cET also checks for 'close' and 'doctype', PyET does it only at need
        for event in ('start', 'data', 'end', 'comment', 'pi'):
            with self.assertRaisesRegex(ValueError, event):
                ET.XMLParser(target=RaisingBuilder(event))

        ET.XMLParser(target=RaisingBuilder(what=AttributeError))
        for event in ('start', 'data', 'end', 'comment', 'pi'):
            parser = ET.XMLParser(target=RaisingBuilder(event, what=AttributeError))
            parser.feed(self.sample1)
            self.assertIsNone(parser.close())


class XMLParserTest(unittest.TestCase):
    sample1 = b'<file><line>22</line></file>'
    sample2 = (b'<!DOCTYPE html PUBLIC'
        b' "-//W3C//DTD XHTML 1.0 Transitional//EN"'
        b' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">'
        b'<html>text</html>')
    sample3 = ('<?xml version="1.0" encoding="iso-8859-1"?>\n'
        '<money value="$\xa3\u20ac\U0001017b">$\xa3\u20ac\U0001017b</money>')

    def _check_sample_element(self, e):
        self.assertEqual(e.tag, 'file')
        self.assertEqual(e[0].tag, 'line')
        self.assertEqual(e[0].text, '22')

    def test_constructor_args(self):
        # Positional args. The first (html) is not supported, but should be
        # nevertheless correctly accepted.
        parser = ET.XMLParser(None, ET.TreeBuilder(), 'utf-8')
        parser.feed(self.sample1)
        self._check_sample_element(parser.close())

        # Now as keyword args.
        parser2 = ET.XMLParser(encoding='utf-8',
                               html=[{}],
                               target=ET.TreeBuilder())
        parser2.feed(self.sample1)
        self._check_sample_element(parser2.close())

    def test_subclass(self):
        class MyParser(ET.XMLParser):
            pass
        parser = MyParser()
        parser.feed(self.sample1)
        self._check_sample_element(parser.close())

    def test_doctype_warning(self):
        parser = ET.XMLParser()
        with self.assertWarns(DeprecationWarning):
            parser.doctype('html', '-//W3C//DTD XHTML 1.0 Transitional//EN',
                'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd')
        parser.feed('<html/>')
        parser.close()

        with warnings.catch_warnings():
            warnings.simplefilter('error', DeprecationWarning)
            parser = ET.XMLParser()
            parser.feed(self.sample2)
            parser.close()

    def test_subclass_doctype(self):
        _doctype = None
        class MyParserWithDoctype(ET.XMLParser):
            def doctype(self, name, pubid, system):
                nonlocal _doctype
                _doctype = (name, pubid, system)

        parser = MyParserWithDoctype()
        with self.assertWarns(DeprecationWarning):
            parser.feed(self.sample2)
        parser.close()
        self.assertEqual(_doctype,
            ('html', '-//W3C//DTD XHTML 1.0 Transitional//EN',
             'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'))

        _doctype = _doctype2 = None
        with warnings.catch_warnings():
            warnings.simplefilter('error', DeprecationWarning)
            class DoctypeParser:
                def doctype(self, name, pubid, system):
                    nonlocal _doctype2
                    _doctype2 = (name, pubid, system)

            parser = MyParserWithDoctype(target=DoctypeParser())
            parser.feed(self.sample2)
            parser.close()
            self.assertIsNone(_doctype)
            self.assertEqual(_doctype2,
                ('html', '-//W3C//DTD XHTML 1.0 Transitional//EN',
                 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'))

    def test_inherited_doctype(self):
        '''Ensure that ordinary usage is not deprecated (Issue 19176)'''
        with warnings.catch_warnings():
            warnings.simplefilter('error', DeprecationWarning)
            class MyParserWithoutDoctype(ET.XMLParser):
                pass
            parser = MyParserWithoutDoctype()
            parser.feed(self.sample2)
            parser.close()

    def test_parse_string(self):
        parser = ET.XMLParser(target=ET.TreeBuilder())
        parser.feed(self.sample3)
        e = parser.close()
        self.assertEqual(e.tag, 'money')
        self.assertEqual(e.attrib['value'], '$\xa3\u20ac\U0001017b')
        self.assertEqual(e.text, '$\xa3\u20ac\U0001017b')


class NamespaceParseTest(unittest.TestCase):
    def test_find_with_namespace(self):
        nsmap = {'h': 'hello', 'f': 'foo'}
        doc = ET.fromstring(SAMPLE_XML_NS_ELEMS)

        self.assertEqual(len(doc.findall('{hello}table', nsmap)), 1)
        self.assertEqual(len(doc.findall('.//{hello}td', nsmap)), 2)
        self.assertEqual(len(doc.findall('.//{foo}name', nsmap)), 1)


class ElementSlicingTest(unittest.TestCase):
    def _elem_tags(self, elemlist):
        return [e.tag for e in elemlist]

    def _subelem_tags(self, elem):
        return self._elem_tags(list(elem))

    def _make_elem_with_children(self, numchildren):
        """Create an Element with a tag 'a', with the given amount of children
           named 'a0', 'a1' ... and so on.

        """
        e = ET.Element('a')
        for i in range(numchildren):
            ET.SubElement(e, 'a%s' % i)
        return e

    def test_getslice_single_index(self):
        e = self._make_elem_with_children(10)

        self.assertEqual(e[1].tag, 'a1')
        self.assertEqual(e[-2].tag, 'a8')

        self.assertRaises(IndexError, lambda: e[12])
        self.assertRaises(IndexError, lambda: e[-12])

    def test_getslice_range(self):
        e = self._make_elem_with_children(6)

        self.assertEqual(self._elem_tags(e[3:]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:6]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:16]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:5]), ['a3', 'a4'])
        self.assertEqual(self._elem_tags(e[3:-1]), ['a3', 'a4'])
        self.assertEqual(self._elem_tags(e[:2]), ['a0', 'a1'])

    def test_getslice_steps(self):
        e = self._make_elem_with_children(10)

        self.assertEqual(self._elem_tags(e[8:10:1]), ['a8', 'a9'])
        self.assertEqual(self._elem_tags(e[::3]), ['a0', 'a3', 'a6', 'a9'])
        self.assertEqual(self._elem_tags(e[::8]), ['a0', 'a8'])
        self.assertEqual(self._elem_tags(e[1::8]), ['a1', 'a9'])
        self.assertEqual(self._elem_tags(e[3::sys.maxsize]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::sys.maxsize<<64]), ['a3'])

    def test_getslice_negative_steps(self):
        e = self._make_elem_with_children(4)

        self.assertEqual(self._elem_tags(e[::-1]), ['a3', 'a2', 'a1', 'a0'])
        self.assertEqual(self._elem_tags(e[::-2]), ['a3', 'a1'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize-1]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize<<64]), ['a3'])

    def test_delslice(self):
        e = self._make_elem_with_children(4)
        del e[0:2]
        self.assertEqual(self._subelem_tags(e), ['a2', 'a3'])

        e = self._make_elem_with_children(4)
        del e[0:]
        self.assertEqual(self._subelem_tags(e), [])

        e = self._make_elem_with_children(4)
        del e[::-1]
        self.assertEqual(self._subelem_tags(e), [])

        e = self._make_elem_with_children(4)
        del e[::-2]
        self.assertEqual(self._subelem_tags(e), ['a0', 'a2'])

        e = self._make_elem_with_children(4)
        del e[1::2]
        self.assertEqual(self._subelem_tags(e), ['a0', 'a2'])

        e = self._make_elem_with_children(2)
        del e[::2]
        self.assertEqual(self._subelem_tags(e), ['a1'])

    def test_setslice_single_index(self):
        e = self._make_elem_with_children(4)
        e[1] = ET.Element('b')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])

        e[-2] = ET.Element('c')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'c', 'a3'])

        with self.assertRaises(IndexError):
            e[5] = ET.Element('d')
        with self.assertRaises(IndexError):
            e[-5] = ET.Element('d')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'c', 'a3'])

    def test_setslice_range(self):
        e = self._make_elem_with_children(4)
        e[1:3] = [ET.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'b1', 'a3'])

        e = self._make_elem_with_children(4)
        e[1:3] = [ET.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a3'])

        e = self._make_elem_with_children(4)
        e[1:3] = [ET.Element('b%s' % i) for i in range(3)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'b1', 'b2', 'a3'])

    def test_setslice_steps(self):
        e = self._make_elem_with_children(6)
        e[1:5:2] = [ET.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'a2', 'b1', 'a4', 'a5'])

        e = self._make_elem_with_children(6)
        with self.assertRaises(ValueError):
            e[1:5:2] = [ET.Element('b')]
        with self.assertRaises(ValueError):
            e[1:5:2] = [ET.Element('b%s' % i) for i in range(3)]
        with self.assertRaises(ValueError):
            e[1:5:2] = []
        self.assertEqual(self._subelem_tags(e), ['a0', 'a1', 'a2', 'a3', 'a4', 'a5'])

        e = self._make_elem_with_children(4)
        e[1::sys.maxsize] = [ET.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])
        e[1::sys.maxsize<<64] = [ET.Element('c')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'c', 'a2', 'a3'])

    def test_setslice_negative_steps(self):
        e = self._make_elem_with_children(4)
        e[2:0:-1] = [ET.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b1', 'b0', 'a3'])

        e = self._make_elem_with_children(4)
        with self.assertRaises(ValueError):
            e[2:0:-1] = [ET.Element('b')]
        with self.assertRaises(ValueError):
            e[2:0:-1] = [ET.Element('b%s' % i) for i in range(3)]
        with self.assertRaises(ValueError):
            e[2:0:-1] = []
        self.assertEqual(self._subelem_tags(e), ['a0', 'a1', 'a2', 'a3'])

        e = self._make_elem_with_children(4)
        e[1::-sys.maxsize] = [ET.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])
        e[1::-sys.maxsize-1] = [ET.Element('c')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'c', 'a2', 'a3'])
        e[1::-sys.maxsize<<64] = [ET.Element('d')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'd', 'a2', 'a3'])


class IOTest(unittest.TestCase):
    def test_encoding(self):
        # Test encoding issues.
        elem = ET.Element("tag")
        elem.text = "abc"
        self.assertEqual(serialize(elem), '<tag>abc</tag>')
        for enc in ("utf-8", "us-ascii"):
            with self.subTest(enc):
                self.assertEqual(serialize(elem, encoding=enc),
                        b'<tag>abc</tag>')
                self.assertEqual(serialize(elem, encoding=enc.upper()),
                        b'<tag>abc</tag>')
        for enc in ("iso-8859-1", "utf-16", "utf-32"):
            with self.subTest(enc):
                self.assertEqual(serialize(elem, encoding=enc),
                        ("<?xml version='1.0' encoding='%s'?>\n"
                         "<tag>abc</tag>" % enc).encode(enc))
                upper = enc.upper()
                self.assertEqual(serialize(elem, encoding=upper),
                        ("<?xml version='1.0' encoding='%s'?>\n"
                         "<tag>abc</tag>" % upper).encode(enc))

        elem = ET.Element("tag")
        elem.text = "<&\"\'>"
        self.assertEqual(serialize(elem), '<tag>&lt;&amp;"\'&gt;</tag>')
        self.assertEqual(serialize(elem, encoding="utf-8"),
                b'<tag>&lt;&amp;"\'&gt;</tag>')
        self.assertEqual(serialize(elem, encoding="us-ascii"),
                b'<tag>&lt;&amp;"\'&gt;</tag>')
        for enc in ("iso-8859-1", "utf-16", "utf-32"):
            self.assertEqual(serialize(elem, encoding=enc),
                    ("<?xml version='1.0' encoding='%s'?>\n"
                     "<tag>&lt;&amp;\"'&gt;</tag>" % enc).encode(enc))

        elem = ET.Element("tag")
        elem.attrib["key"] = "<&\"\'>"
        self.assertEqual(serialize(elem), '<tag key="&lt;&amp;&quot;\'&gt;" />')
        self.assertEqual(serialize(elem, encoding="utf-8"),
                b'<tag key="&lt;&amp;&quot;\'&gt;" />')
        self.assertEqual(serialize(elem, encoding="us-ascii"),
                b'<tag key="&lt;&amp;&quot;\'&gt;" />')
        for enc in ("iso-8859-1", "utf-16", "utf-32"):
            self.assertEqual(serialize(elem, encoding=enc),
                    ("<?xml version='1.0' encoding='%s'?>\n"
                     "<tag key=\"&lt;&amp;&quot;'&gt;\" />" % enc).encode(enc))

        elem = ET.Element("tag")
        elem.text = '\xe5\xf6\xf6<>'
        self.assertEqual(serialize(elem), '<tag>\xe5\xf6\xf6&lt;&gt;</tag>')
        self.assertEqual(serialize(elem, encoding="utf-8"),
                b'<tag>\xc3\xa5\xc3\xb6\xc3\xb6&lt;&gt;</tag>')
        self.assertEqual(serialize(elem, encoding="us-ascii"),
                b'<tag>&#229;&#246;&#246;&lt;&gt;</tag>')
        for enc in ("iso-8859-1", "utf-16", "utf-32"):
            self.assertEqual(serialize(elem, encoding=enc),
                    ("<?xml version='1.0' encoding='%s'?>\n"
                     "<tag>Ã¥Ã¶Ã¶&lt;&gt;</tag>" % enc).encode(enc))

        elem = ET.Element("tag")
        elem.attrib["key"] = '\xe5\xf6\xf6<>'
        self.assertEqual(serialize(elem), '<tag key="\xe5\xf6\xf6&lt;&gt;" />')
        self.assertEqual(serialize(elem, encoding="utf-8"),
                b'<tag key="\xc3\xa5\xc3\xb6\xc3\xb6&lt;&gt;" />')
        self.assertEqual(serialize(elem, encoding="us-ascii"),
                b'<tag key="&#229;&#246;&#246;&lt;&gt;" />')
        for enc in ("iso-8859-1", "utf-16", "utf-16le", "utf-16be", "utf-32"):
            self.assertEqual(serialize(elem, encoding=enc),
                    ("<?xml version='1.0' encoding='%s'?>\n"
                     "<tag key=\"Ã¥Ã¶Ã¶&lt;&gt;\" />" % enc).encode(enc))

    def test_write_to_filename(self):
        self.addCleanup(support.unlink, TESTFN)
        tree = ET.ElementTree(ET.XML('''<site />'''))
        tree.write(TESTFN)
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(), b'''<site />''')

    def test_write_to_text_file(self):
        self.addCleanup(support.unlink, TESTFN)
        tree = ET.ElementTree(ET.XML('''<site />'''))
        with open(TESTFN, 'w', encoding='utf-8') as f:
            tree.write(f, encoding='unicode')
            self.assertFalse(f.closed)
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(), b'''<site />''')

    def test_write_to_binary_file(self):
        self.addCleanup(support.unlink, TESTFN)
        tree = ET.ElementTree(ET.XML('''<site />'''))
        with open(TESTFN, 'wb') as f:
            tree.write(f)
            self.assertFalse(f.closed)
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(), b'''<site />''')

    def test_write_to_binary_file_with_bom(self):
        self.addCleanup(support.unlink, TESTFN)
        tree = ET.ElementTree(ET.XML('''<site />'''))
        # test BOM writing to buffered file
        with open(TESTFN, 'wb') as f:
            tree.write(f, encoding='utf-16')
            self.assertFalse(f.closed)
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(),
                    '''<?xml version='1.0' encoding='utf-16'?>\n'''
                    '''<site />'''.encode("utf-16"))
        # test BOM writing to non-buffered file
        with open(TESTFN, 'wb', buffering=0) as f:
            tree.write(f, encoding='utf-16')
            self.assertFalse(f.closed)
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(),
                    '''<?xml version='1.0' encoding='utf-16'?>\n'''
                    '''<site />'''.encode("utf-16"))

    def test_read_from_stringio(self):
        tree = ET.ElementTree()
        stream = io.StringIO('''<?xml version="1.0"?><site></site>''')
        tree.parse(stream)
        self.assertEqual(tree.getroot().tag, 'site')

    def test_write_to_stringio(self):
        tree = ET.ElementTree(ET.XML('''<site />'''))
        stream = io.StringIO()
        tree.write(stream, encoding='unicode')
        self.assertEqual(stream.getvalue(), '''<site />''')

    def test_read_from_bytesio(self):
        tree = ET.ElementTree()
        raw = io.BytesIO(b'''<?xml version="1.0"?><site></site>''')
        tree.parse(raw)
        self.assertEqual(tree.getroot().tag, 'site')

    def test_write_to_bytesio(self):
        tree = ET.ElementTree(ET.XML('''<site />'''))
        raw = io.BytesIO()
        tree.write(raw)
        self.assertEqual(raw.getvalue(), b'''<site />''')

    class dummy:
        pass

    def test_read_from_user_text_reader(self):
        stream = io.StringIO('''<?xml version="1.0"?><site></site>''')
        reader = self.dummy()
        reader.read = stream.read
        tree = ET.ElementTree()
        tree.parse(reader)
        self.assertEqual(tree.getroot().tag, 'site')

    def test_write_to_user_text_writer(self):
        tree = ET.ElementTree(ET.XML('''<site />'''))
        stream = io.StringIO()
        writer = self.dummy()
        writer.write = stream.write
        tree.write(writer, encoding='unicode')
        self.assertEqual(stream.getvalue(), '''<site />''')

    def test_read_from_user_binary_reader(self):
        raw = io.BytesIO(b'''<?xml version="1.0"?><site></site>''')
        reader = self.dummy()
        reader.read = raw.read
        tree = ET.ElementTree()
        tree.parse(reader)
        self.assertEqual(tree.getroot().tag, 'site')
        tree = ET.ElementTree()

    def test_write_to_user_binary_writer(self):
        tree = ET.ElementTree(ET.XML('''<site />'''))
        raw = io.BytesIO()
        writer = self.dummy()
        writer.write = raw.write
        tree.write(writer)
        self.assertEqual(raw.getvalue(), b'''<site />''')

    def test_write_to_user_binary_writer_with_bom(self):
        tree = ET.ElementTree(ET.XML('''<site />'''))
        raw = io.BytesIO()
        writer = self.dummy()
        writer.write = raw.write
        writer.seekable = lambda: True
        writer.tell = raw.tell
        tree.write(writer, encoding="utf-16")
        self.assertEqual(raw.getvalue(),
                '''<?xml version='1.0' encoding='utf-16'?>\n'''
                '''<site />'''.encode("utf-16"))

    def test_tostringlist_invariant(self):
        root = ET.fromstring('<tag>foo</tag>')
        self.assertEqual(
            ET.tostring(root, 'unicode'),
            ''.join(ET.tostringlist(root, 'unicode')))
        self.assertEqual(
            ET.tostring(root, 'utf-16'),
            b''.join(ET.tostringlist(root, 'utf-16')))

    def test_short_empty_elements(self):
        root = ET.fromstring('<tag>a<x />b<y></y>c</tag>')
        self.assertEqual(
            ET.tostring(root, 'unicode'),
            '<tag>a<x />b<y />c</tag>')
        self.assertEqual(
            ET.tostring(root, 'unicode', short_empty_elements=True),
            '<tag>a<x />b<y />c</tag>')
        self.assertEqual(
            ET.tostring(root, 'unicode', short_empty_elements=False),
            '<tag>a<x></x>b<y></y>c</tag>')


class ParseErrorTest(unittest.TestCase):
    def test_subclass(self):
        self.assertIsInstance(ET.ParseError(), SyntaxError)

    def _get_error(self, s):
        try:
            ET.fromstring(s)
        except ET.ParseError as e:
            return e

    def test_error_position(self):
        self.assertEqual(self._get_error('foo').position, (1, 0))
        self.assertEqual(self._get_error('<tag>&foo;</tag>').position, (1, 5))
        self.assertEqual(self._get_error('foobar<').position, (1, 6))

    def test_error_code(self):
        import xml.parsers.expat.errors as ERRORS
        self.assertEqual(self._get_error('foo').code,
                ERRORS.codes[ERRORS.XML_ERROR_SYNTAX])


class KeywordArgsTest(unittest.TestCase):
    # Test various issues with keyword arguments passed to ET.Element
    # constructor and methods
    def test_issue14818(self):
        x = ET.XML("<a>foo</a>")
        self.assertEqual(x.find('a', None),
                         x.find(path='a', namespaces=None))
        self.assertEqual(x.findtext('a', None, None),
                         x.findtext(path='a', default=None, namespaces=None))
        self.assertEqual(x.findall('a', None),
                         x.findall(path='a', namespaces=None))
        self.assertEqual(list(x.iterfind('a', None)),
                         list(x.iterfind(path='a', namespaces=None)))

        self.assertEqual(ET.Element('a').attrib, {})
        elements = [
            ET.Element('a', dict(href="#", id="foo")),
            ET.Element('a', attrib=dict(href="#", id="foo")),
            ET.Element('a', dict(href="#"), id="foo"),
            ET.Element('a', href="#", id="foo"),
            ET.Element('a', dict(href="#", id="foo"), href="#", id="foo"),
        ]
        for e in elements:
            self.assertEqual(e.tag, 'a')
            self.assertEqual(e.attrib, dict(href="#", id="foo"))

        e2 = ET.SubElement(elements[0], 'foobar', attrib={'key1': 'value1'})
        self.assertEqual(e2.attrib['key1'], 'value1')

        with self.assertRaisesRegex(TypeError, 'must be dict, not str'):
            ET.Element('a', "I'm not a dict")
        with self.assertRaisesRegex(TypeError, 'must be dict, not str'):
            ET.Element('a', attrib="I'm not a dict")

# --------------------------------------------------------------------

class NoAcceleratorTest(unittest.TestCase):
    def setUp(self):
        if not pyET:
            raise unittest.SkipTest('only for the Python version')

    # Test that the C accelerator was not imported for pyET
    def test_correct_import_pyET(self):
        # The type of methods defined in Python code is types.FunctionType,
        # while the type of methods defined inside _elementtree is
        # <class 'wrapper_descriptor'>
        self.assertIsInstance(pyET.Element.__init__, types.FunctionType)
        self.assertIsInstance(pyET.XMLParser.__init__, types.FunctionType)

# --------------------------------------------------------------------


class CleanContext(object):
    """Provide default namespace mapping and path cache."""
    checkwarnings = None

    def __init__(self, quiet=False):
        if sys.flags.optimize >= 2:
            # under -OO, doctests cannot be run and therefore not all warnings
            # will be emitted
            quiet = True
        deprecations = (
            # Search behaviour is broken if search path starts with "/".
            ("This search is broken in 1.3 and earlier, and will be fixed "
             "in a future version.  If you rely on the current behaviour, "
             "change it to '.+'", FutureWarning),
            # Element.getchildren() and Element.getiterator() are deprecated.
            ("This method will be removed in future versions.  "
             "Use .+ instead.", DeprecationWarning),
            ("This method will be removed in future versions.  "
             "Use .+ instead.", PendingDeprecationWarning))
        self.checkwarnings = support.check_warnings(*deprecations, quiet=quiet)

    def __enter__(self):
        from xml.etree import ElementPath
        self._nsmap = ET.register_namespace._namespace_map
        # Copy the default namespace mapping
        self._nsmap_copy = self._nsmap.copy()
        # Copy the path cache (should be empty)
        self._path_cache = ElementPath._cache
        ElementPath._cache = self._path_cache.copy()
        self.checkwarnings.__enter__()

    def __exit__(self, *args):
        from xml.etree import ElementPath
        # Restore mapping and path cache
        self._nsmap.clear()
        self._nsmap.update(self._nsmap_copy)
        ElementPath._cache = self._path_cache
        self.checkwarnings.__exit__(*args)


def test_main(module=None):
    # When invoked without a module, runs the Python ET tests by loading pyET.
    # Otherwise, uses the given module as the ET.
    global pyET
    pyET = import_fresh_module('xml.etree.ElementTree',
                               blocked=['_elementtree'])
    if module is None:
        module = pyET

    global ET
    ET = module

    test_classes = [
        ModuleTest,
        ElementSlicingTest,
        BasicElementTest,
        BadElementTest,
        BadElementPathTest,
        ElementTreeTest,
        IOTest,
        ParseErrorTest,
        XIncludeTest,
        ElementTreeTypeTest,
        ElementFindTest,
        ElementIterTest,
        TreeBuilderTest,
        XMLParserTest,
        XMLPullParserTest,
        BugsTest,
        ]

    # These tests will only run for the pure-Python version that doesn't import
    # _elementtree. We can't use skipUnless here, because pyET is filled in only
    # after the module is loaded.
    if pyET is not ET:
        test_classes.extend([
            NoAcceleratorTest,
            ])

    try:
        # XXX the C module should give the same warnings as the Python module
        with CleanContext(quiet=(pyET is not ET)):
            support.run_unittest(*test_classes)
    finally:
        # don't interfere with subsequent tests
        ET = pyET = None


if __name__ == '__main__':
    test_main()
