text: """
  Tests for on-the-fly content compression encoding.
  """
  from io   import BytesIO
  from gzip import GzipFile
  
  from zope.interface import implementer
  
  from twisted.trial.unittest import TestCase
  from twisted.internet.defer import succeed
  
  from nevow.inevow import IResource, IRequest
  from nevow.testutil import FakeRequest
  from nevow.context import RequestContext
  from nevow.appserver import errorMarker
  from nevow.rend import NotFound
  from nevow.compression import CompressingResourceWrapper, CompressingRequestWrapper
  from nevow.compression import parseAcceptEncoding, _ProxyDescriptor
  
  
  class HeaderTests(TestCase):
      """
      Tests for header parsing.
      """
      def test_parseAcceptEncoding(self):
          """
          Test the parsing of a variety of Accept-Encoding field values.
          """
          cases = [
              ('compress, gzip',
               {'compress': 1.0, 'gzip': 1.0, 'identity': 0.0001}),
              ('',
               {'identity': 0.0001}),
              ('*',
               {'*': 1}),
              ('compress;q=0.5, gzip;q=1.0',
               {'compress': 0.5, 'gzip': 1.0, 'identity': 0.0001}),
              ('gzip;q=1.0, identity;q=0.5, *;q=0',
               {'gzip': 1.0, 'identity': 0.5, '*': 0})
              ]
  
          for value, result in cases:
              self.assertEqual(parseAcceptEncoding(value), result, msg='error parsing %r' % value)
  
  
  
  class _Dummy(object):
      """
      Dummy object just to get an instance dict.
      """
  
  
  
  class _Wrapper(object):
      """
      Test wrapper.
      """
      x = _ProxyDescriptor('x')
      y = _ProxyDescriptor('y')
  
      def __init__(self, underlying):
          self.underlying = underlying
  
  
  
  class ProxyDescriptorTests(TestCase):
      """
      Tests for L{_ProxyDescriptor}.
      """
      def setUp(self):
          """
          Set up a dummy object and a wrapper for it.
          """
          self.dummy = _Dummy()
          self.dummy.x = object()
          self.dummy.y = object()
          self.wrapper = _Wrapper(self.dummy)
  
  
      def test_proxyGet(self):
          """
          Getting a proxied attribute should retrieve the underlying attribute.
          """
          self.assertIdentical(self.wrapper.x, self.dummy.x)
          self.assertIdentical(self.wrapper.y, self.dummy.y)
          self.dummy.x = object()
          self.assertIdentical(self.wrapper.x, self.dummy.x)
  
  
      def test_proxyClassGet(self):
          """
          Getting a proxied attribute from the class should just retrieve the
          descriptor.
          """
          self.assertIdentical(_Wrapper.x, _Wrapper.__dict__['x'])
  
  
      def test_proxySet(self):
          """
          Setting a proxied attribute should set the underlying attribute.
          """
          self.wrapper.x = object()
          self.assertIdentical(self.dummy.x, self.wrapper.x)
          self.wrapper.y = 5
          self.assertEqual(self.dummy.y, 5)
  
  
      def test_proxyDelete(self):
          """
          Deleting a proxied attribute should delete the underlying attribute.
          """
          self.assertTrue(hasattr(self.dummy, 'x'))
          del self.wrapper.x
          self.assertFalse(hasattr(self.dummy, 'x'))
  
  
  
  class RequestWrapperTests(TestCase):
      """
      Tests for L{CompressingRequestWrapper}.
      """
      def setUp(self):
          """
          Wrap a request fake to test the wrapper.
          """
          self.request = FakeRequest()
          self.wrapper = CompressingRequestWrapper(self.request)
  
  
      def test_attributes(self):
          """
          Attributes on the wrapper should be forwarded to the underlying
          request.
          """
          attributes = ['method', 'uri', 'path', 'args', 'requestHeaders']
          for attrName in attributes:
              self.assertIdentical(getattr(self.wrapper, attrName),
                                   getattr(self.request, attrName))
  
  
      def test_missingAttributes(self):
          """
          Attributes that are not part of the interfaces being proxied should not
          be proxied.
          """
          self.assertRaises(AttributeError, getattr, self.wrapper, 'doesntexist')
          self.request._privateTestAttribute = 42
          self.assertRaises(AttributeError, getattr, self.wrapper, '_privateTestAttribute')
  
  
      def test_contentLength(self):
          """
          Content-Length header should be discarded when compression is in use.
          """
          self.assertFalse(
              self.request.responseHeaders.hasHeader('content-length'))
          self.wrapper.setHeader('content-length', '1234')
          self.assertFalse(
              self.request.responseHeaders.hasHeader('content-length'))
  
          self.request.setHeader('content-length', '1234')
          self.wrapper = CompressingRequestWrapper(self.request)
          self.assertFalse(
              self.request.responseHeaders.hasHeader('content-length'))
  
  
      def test_responseHeaders(self):
          """
          Content-Encoding header should be set appropriately.
          """
          self.assertEqual(
              self.request.responseHeaders.getRawHeaders('content-encoding'),
              ['gzip'])
  
  
      def test_lazySetup(self):
          """
          The gzip prelude should only be written once real data is written.
  
          This is necessary to avoid terminating the header too quickly.
          """
          self.assertEqual(self.request.accumulator, b'')
          self.wrapper.write(b'foo')
          self.assertNotEqual(self.request.accumulator, b'')
  
  
      def _ungzip(self, data):
          """
          Un-gzip some data.
          """
          s = BytesIO(data)
          return GzipFile(fileobj=s, mode='rb').read()
  
  
      def test_encoding(self):
          """
          Response content should be written out in compressed format.
          """
          self.wrapper.write(b'foo')
          self.wrapper.write(b'bar')
          self.wrapper.finishRequest(True)
          self.assertEqual(self._ungzip(self.request.accumulator), b'foobar')
  
  
      def test_finish(self):
          """
          Calling C{finishRequest()} on the wrapper should cause the underlying
          implementation to be called.
          """
          self.wrapper.finishRequest(True)
          self.assertTrue(self.request.finished)
  
  
  @implementer(IResource)
  class TestResource(object):
      """
      L{IResource} implementation for testing.
  
      @ivar lastRequest: The last request we were rendered with.
      @type lastRequest: L{IRequest} or C{None}
      @ivar segments: The segments we were constructed with.
      @type segments: C{list}
      @ivar html: The data to return from C{renderHTTP}.
      """
  
      lastRequest = None
  
      def __init__(self, segments=[], html=b'o hi'):
          self.segments = segments
          self.html = html
  
  
      def locateChild(self, ctx, segments):
          """
          Construct a new resource of our type.
  
          We hand out child resources for any segments, as this is the simplest
          thing to do.
          """
          return type(self)(segments), []
  
  
      def renderHTTP(self, ctx):
          """
          Stash the request for later inspection.
          """
          self.lastRequest = IRequest(ctx)
          return self.html
  
  
  @implementer(IResource)
  class TestChildlessResource(object):
      """
      L{IResource} implementation with no children.
      """
  
      def locateChild(self, ctx, segments):
          """
          Always return C{NotFound}.
          """
          return NotFound
  
  
  @implementer(IResource)
  class TestDeferredResource(object):
      """
      L{IResource} implementation with children.
      """
  
      def locateChild(self, ctx, segments):
          """
          Construct a new resource of our type.
  
          We hand out child resources for any segments, but the resource itself
          is wrapped in a deferred.
          """
          return succeed(type(self)()), []
  
  
  class TestResourceWrapper(CompressingResourceWrapper):
      """
      Subclass for testing purposes, just to create a new type.
      """
  
  
  @implementer(IResource)
  class TestBrokenResource(object):
      """
      L{IResource} implementation that returns garbage from C{locateChild}.
      """
  
      def locateChild(self, ctx, segments):
          """
          Return some garbage.
          """
          return 42
  
  
  class ResourceWrapper(TestCase):
      """
      Tests for L{CompressingResourceWrapper}.
  
      @ivar resource: The underlying resource for testing.
      @type resource: L{TestResource}
      @ivar wrapped: The wrapped resource.
      @type wrapped: L{CompressingResourceWrapper}
      @ivar request: A fake request.
      @type request: L{FakeRequest}
      @ivar ctx: A dummy context.
      @type ctx: L{RequestContext}
      """
      def setUp(self):
          self.resource = TestResource()
          self.wrapped = CompressingResourceWrapper(self.resource)
          self.request = FakeRequest()
          self.ctx = RequestContext(tag=self.request)
  
  
      def test_rendering(self):
          """
          Rendering a wrapped resource renders the underlying resource with a
          wrapped request if compression is available.
          """
          self.wrapped.canCompress = lambda req: True
          self.wrapped.renderHTTP(self.ctx)
          self.assertEqual(type(self.resource.lastRequest), CompressingRequestWrapper)
          self.assertIdentical(self.resource.lastRequest.underlying, self.request)
  
  
      def test_renderingUnwrapped(self):
          """
          Rendering a wrapped resource renders the underlying resource with an
          unwrapped request if compression is not available.
          """
          self.wrapped.canCompress = lambda req: False
          self.wrapped.renderHTTP(self.ctx)
          self.assertIdentical(self.resource.lastRequest, self.request)
  
  
      def test_awfulHack(self):
          """
          Rendering a wrapped resource should finish off the request, and return
          a special sentinel value to prevent the Site machinery from trying to
          finish it again.
          """
          def _cbCheckReturn(result):
              self.rendered = True
              self.assertIdentical(result, errorMarker)
              self.assertTrue(self.request.finished)
  
          self.rendered = False
          self.wrapped.canCompress = lambda req: True
  
          return self.wrapped.renderHTTP(self.ctx)\
                  .addCallback(_cbCheckReturn)
          # The callback should run synchronously
          #self.assertTrue(self.rendered)
  
  
      def test_rendering(self):
          """
          Returning something other than C{str} causes the value to be passed
          through.
          """
          def _cbResult(result):
              self.result = result
  
          marker = object()
          self.resource.html = marker
          self.wrapped.canCompress = lambda req: True
          self.wrapped.renderHTTP(self.ctx).addCallback(_cbResult)
          self.assertIdentical(marker, self.result)
  
  
      def _cbCheckChild(self, result):
          """
          Check that the child resource is wrapped correctly.
          """
          self.checked = True
  
  
      def _locateChild(self, resource, segments):
          """
          Helper function for retrieving a child synchronously.
          """
          def _cbGotChild(result):
              self.gotChild = True
              self.result = result
  
          def _ebChild(f):
              self.gotChild = 'error'
              self.f = f
  
          self.gotChild = False
          resource.locateChild(None, segments).addCallbacks(_cbGotChild, _ebChild)
          self.assertTrue(self.gotChild)
          if self.gotChild == 'error':
              self.f.raiseException()
          return self.result
  
  
      def test_wrapChildren(self):
          """
          Any children of the wrapped resource should also be wrapped.
          """
          self.checked = False
          child, segments = self._locateChild(self.wrapped, ['some', 'child', 'segments'])
          self.assertIdentical(type(child), type(self.wrapped))
          self.assertEqual(child.underlying.segments, ['some', 'child', 'segments'])
  
  
      def test_wrapChildrenSubclass(self):
          """
          The request wrapper should wrap children with the same type.
          """
          self.wrapped = TestResourceWrapper(self.resource)
          self.test_wrapChildren()
  
  
      def test_childNotFound(self):
          """
          The request wrapper should pass C{NotFound} through.
          """
          wrapped = CompressingResourceWrapper(TestChildlessResource())
          result = self._locateChild(wrapped, ['foo'])
          self.assertEqual(result, NotFound)
  
  
      def test_deferredChild(self):
          """
          The wrapper should deal with a resource wrapped in a deferred returned
          from locateChild.
          """
          wrapped = CompressingResourceWrapper(TestDeferredResource())
          child, segments = self._locateChild(wrapped, ['foo'])
          self.assertEqual(type(child.underlying), TestDeferredResource)
          self.assertEqual(segments, [])
  
  
      def test_brokenChild(self):
          """
          C{ValueError} should be raised if the underlying C{locateChild} returns
          something bogus.
          """
          wrapped = CompressingResourceWrapper(TestBrokenResource())
          self.assertRaises(ValueError, self._locateChild, wrapped, ['foo'])
  
  
      def test_negotiation(self):
          """
          Request wrapping should only occur when the client has indicated they
          can accept compression.
          """
          self.assertFalse(self.wrapped.canCompress(self.request))
  
          self.request.requestHeaders.setRawHeaders(
              'accept-encoding', ['foo;q=1.0, bar;q=0.5, baz'])
          self.assertFalse(self.wrapped.canCompress(self.request))
  
          self.request.requestHeaders.setRawHeaders('accept-encoding', ['gzip'])
          self.assertTrue(self.wrapped.canCompress(self.request))
  
          self.request.requestHeaders.setRawHeaders(
              'accept-encoding', ['gzip;q=0.5'])
          self.assertTrue(self.wrapped.canCompress(self.request))
  
          self.request.requestHeaders.setRawHeaders(
              'accept-encoding', ['gzip;q=0'])
          self.assertFalse(self.wrapped.canCompress(self.request))
  