text: # Python test set -- part 1, grammar.
  # This just tests whether the parser accepts them all.
  
  from test.support import check_syntax_error, check_impl_detail
  import inspect
  import unittest
  import sys
  # testing import *
  from sys import *
  
  # different import patterns to check that __annotations__ does not interfere
  # with import machinery
  import test.ann_module as ann_module
  import typing
  from collections import ChainMap
  from test import ann_module2
  import test
  
  # These are shared with test_tokenize and other test modules.
  #
  # Note: since several test cases filter out floats by looking for "e" and ".",
  # don't add hexadecimal literals that contain "e" or "E".
  VALID_UNDERSCORE_LITERALS = [
      '0_0_0',
      '4_2',
      '1_0000_0000',
      '0b1001_0100',
      '0xffff_ffff',
      '0o5_7_7',
      '1_00_00.5',
      '1_00_00.5e5',
      '1_00_00e5_1',
      '1e1_0',
      '.1_4',
      '.1_4e1',
      '0b_0',
      '0x_f',
      '0o_5',
      '1_00_00j',
      '1_00_00.5j',
      '1_00_00e5_1j',
      '.1_4j',
      '(1_2.5+3_3j)',
      '(.5_6j)',
  ]
  INVALID_UNDERSCORE_LITERALS = [
      # Trailing underscores:
      '0_',
      '42_',
      '1.4j_',
      '0x_',
      '0b1_',
      '0xf_',
      '0o5_',
      '0 if 1_Else 1',
      # Underscores in the base selector:
      '0_b0',
      '0_xf',
      '0_o5',
      # Old-style octal, still disallowed:
      '0_7',
      '09_99',
      # Multiple consecutive underscores:
      '4_______2',
      '0.1__4',
      '0.1__4j',
      '0b1001__0100',
      '0xffff__ffff',
      '0x___',
      '0o5__77',
      '1e1__0',
      '1e1__0j',
      # Underscore right before a dot:
      '1_.4',
      '1_.4j',
      # Underscore right after a dot:
      '1._4',
      '1._4j',
      '._5',
      '._5j',
      # Underscore right after a sign:
      '1.0e+_1',
      '1.0e+_1j',
      # Underscore right before j:
      '1.4_j',
      '1.4e5_j',
      # Underscore right before e:
      '1_e1',
      '1.4_e1',
      '1.4_e1j',
      # Underscore right after e:
      '1e_1',
      '1.4e_1',
      '1.4e_1j',
      # Complex cases with parens:
      '(1+1.5_j_)',
      '(1+1.5_j)',
  ]
  
  
  class TokenTests(unittest.TestCase):
  
      def test_backslash(self):
          # Backslash means line continuation:
          x = 1 \
          + 1
          self.assertEqual(x, 2, 'backslash for line continuation')
  
          # Backslash does not means continuation in comments :\
          x = 0
          self.assertEqual(x, 0, 'backslash ending comment')
  
      def test_plain_integers(self):
          self.assertEqual(type(000), type(0))
          self.assertEqual(0xff, 255)
          self.assertEqual(0o377, 255)
          self.assertEqual(2147483647, 0o17777777777)
          self.assertEqual(0b1001, 9)
          # "0x" is not a valid literal
          self.assertRaises(SyntaxError, eval, "0x")
          from sys import maxsize
          if maxsize == 2147483647:
              self.assertEqual(-2147483647-1, -0o20000000000)
              # XXX -2147483648
              self.assertTrue(0o37777777777 > 0)
              self.assertTrue(0xffffffff > 0)
              self.assertTrue(0b1111111111111111111111111111111 > 0)
              for s in ('2147483648', '0o40000000000', '0x100000000',
                        '0b10000000000000000000000000000000'):
                  try:
                      x = eval(s)
                  except OverflowError:
                      self.fail("OverflowError on huge integer literal %r" % s)
          elif maxsize == 9223372036854775807:
              self.assertEqual(-9223372036854775807-1, -0o1000000000000000000000)
              self.assertTrue(0o1777777777777777777777 > 0)
              self.assertTrue(0xffffffffffffffff > 0)
              self.assertTrue(0b11111111111111111111111111111111111111111111111111111111111111 > 0)
              for s in '9223372036854775808', '0o2000000000000000000000', \
                       '0x10000000000000000', \
                       '0b100000000000000000000000000000000000000000000000000000000000000':
                  try:
                      x = eval(s)
                  except OverflowError:
                      self.fail("OverflowError on huge integer literal %r" % s)
          else:
              self.fail('Weird maxsize value %r' % maxsize)
  
      def test_long_integers(self):
          x = 0
          x = 0xffffffffffffffff
          x = 0Xffffffffffffffff
          x = 0o77777777777777777
          x = 0O77777777777777777
          x = 123456789012345678901234567890
          x = 0b100000000000000000000000000000000000000000000000000000000000000000000
          x = 0B111111111111111111111111111111111111111111111111111111111111111111111
  
      def test_floats(self):
          x = 3.14
          x = 314.
          x = 0.314
          # XXX x = 000.314
          x = .314
          x = 3e14
          x = 3E14
          x = 3e-14
          x = 3e+14
          x = 3.e14
          x = .3e14
          x = 3.1e4
  
      def test_float_exponent_tokenization(self):
          # See issue 21642.
          self.assertEqual(1 if 1else 0, 1)
          self.assertEqual(1 if 0else 0, 0)
          self.assertRaises(SyntaxError, eval, "0 if 1Else 0")
  
      def test_underscore_literals(self):
          for lit in VALID_UNDERSCORE_LITERALS:
              self.assertEqual(eval(lit), eval(lit.replace('_', '')))
          for lit in INVALID_UNDERSCORE_LITERALS:
              self.assertRaises(SyntaxError, eval, lit)
          # Sanity check: no literal begins with an underscore
          self.assertRaises(NameError, eval, "_0")
  
      def test_string_literals(self):
          x = ''; y = ""; self.assertTrue(len(x) == 0 and x == y)
          x = '\''; y = "'"; self.assertTrue(len(x) == 1 and x == y and ord(x) == 39)
          x = '"'; y = "\""; self.assertTrue(len(x) == 1 and x == y and ord(x) == 34)
          x = "doesn't \"shrink\" does it"
          y = 'doesn\'t "shrink" does it'
          self.assertTrue(len(x) == 24 and x == y)
          x = "does \"shrink\" doesn't it"
          y = 'does "shrink" doesn\'t it'
          self.assertTrue(len(x) == 24 and x == y)
          x = """
  The "quick"
  brown fox
  jumps over
  the 'lazy' dog.
  """
          y = '\nThe "quick"\nbrown fox\njumps over\nthe \'lazy\' dog.\n'
          self.assertEqual(x, y)
          y = '''
  The "quick"
  brown fox
  jumps over
  the 'lazy' dog.
  '''
          self.assertEqual(x, y)
          y = "\n\
  The \"quick\"\n\
  brown fox\n\
  jumps over\n\
  the 'lazy' dog.\n\
  "
          self.assertEqual(x, y)
          y = '\n\
  The \"quick\"\n\
  brown fox\n\
  jumps over\n\
  the \'lazy\' dog.\n\
  '
          self.assertEqual(x, y)
  
      def test_ellipsis(self):
          x = ...
          self.assertTrue(x is Ellipsis)
          self.assertRaises(SyntaxError, eval, ".. .")
  
      def test_eof_error(self):
          samples = ("def foo(", "\ndef foo(", "def foo(\n")
          for s in samples:
              with self.assertRaises(SyntaxError) as cm:
                  compile(s, "<test>", "exec")
              self.assertIn("parenthesis is never closed", str(cm.exception))
  
  var_annot_global: int # a global annotated is necessary for test_var_annot
  
  # custom namespace for testing __annotations__
  
  class CNS:
      def __init__(self):
          self._dct = {}
      def __setitem__(self, item, value):
          self._dct[item.lower()] = value
      def __getitem__(self, item):
          return self._dct[item]
  
  
  class GrammarTests(unittest.TestCase):
  
      # single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
      # XXX can't test in a script -- this rule is only used when interactive
  
      # file_input: (NEWLINE | stmt)* ENDMARKER
      # Being tested as this very moment this very module
  
      # expr_input: testlist NEWLINE
      # XXX Hard to test -- used only in calls to input()
  
      def test_eval_input(self):
          # testlist ENDMARKER
          x = eval('1, 0 or 1')
  
      def test_var_annot_basics(self):
          # all these should be allowed
          var1: int = 5
          var2: [int, str]
          my_lst = [42]
          def one():
              return 1
          int.new_attr: int
          [list][0]: type
          my_lst[one()-1]: int = 5
          self.assertEqual(my_lst, [5])
  
      def test_var_annot_syntax_errors(self):
          # parser pass
          check_syntax_error(self, "def f: int")
          check_syntax_error(self, "x: int: str")
          check_syntax_error(self, "def f():\n"
                                   "    nonlocal x: int\n")
          # AST pass
          check_syntax_error(self, "[x, 0]: int\n")
          check_syntax_error(self, "f(): int\n")
          check_syntax_error(self, "(x,): int")
          check_syntax_error(self, "def f():\n"
                                   "    (x, y): int = (1, 2)\n")
          # symtable pass
          check_syntax_error(self, "def f():\n"
                                   "    x: int\n"
                                   "    global x\n")
          check_syntax_error(self, "def f():\n"
                                   "    global x\n"
                                   "    x: int\n")
  
      def test_var_annot_basic_semantics(self):
          # execution order
          with self.assertRaises(ZeroDivisionError):
              no_name[does_not_exist]: no_name_again = 1/0
          with self.assertRaises(NameError):
              no_name[does_not_exist]: 1/0 = 0
          global var_annot_global
  
          # function semantics
          def f():
              st: str = "Hello"
              a.b: int = (1, 2)
              return st
          self.assertEqual(f.__annotations__, {})
          def f_OK():
              x: 1/0
          f_OK()
          def fbad():
              x: int
              print(x)
          with self.assertRaises(UnboundLocalError):
              fbad()
          def f2bad():
              (no_such_global): int
              print(no_such_global)
          try:
              f2bad()
          except Exception as e:
              self.assertIs(type(e), NameError)
  
          # class semantics
          class C:
              __foo: int
              s: str = "attr"
              z = 2
              def __init__(self, x):
                  self.x: int = x
          self.assertEqual(C.__annotations__, {'_C__foo': int, 's': str})
          with self.assertRaises(NameError):
              class CBad:
                  no_such_name_defined.attr: int = 0
          with self.assertRaises(NameError):
              class Cbad2(C):
                  x: int
                  x.y: list = []
  
      def test_var_annot_metaclass_semantics(self):
          class CMeta(type):
              @classmethod
              def __prepare__(metacls, name, bases, **kwds):
                  return {'__annotations__': CNS()}
          class CC(metaclass=CMeta):
              XX: 'ANNOT'
          self.assertEqual(CC.__annotations__['xx'], 'ANNOT')
  
      def test_var_annot_module_semantics(self):
          with self.assertRaises(AttributeError):
              print(test.__annotations__)
          self.assertEqual(ann_module.__annotations__,
                       {1: 2, 'x': int, 'y': str, 'f': typing.Tuple[int, int]})
          self.assertEqual(ann_module.M.__annotations__,
                                {'123': 123, 'o': type})
          self.assertEqual(ann_module2.__annotations__, {})
  
      def test_var_annot_in_module(self):
          # check that functions fail the same way when executed
          # outside of module where they were defined
          from test.ann_module3 import f_bad_ann, g_bad_ann, D_bad_ann
          with self.assertRaises(NameError):
              f_bad_ann()
          with self.assertRaises(NameError):
              g_bad_ann()
          with self.assertRaises(NameError):
              D_bad_ann(5)
  
      def test_var_annot_simple_exec(self):
          gns = {}; lns= {}
          exec("'docstring'\n"
               "__annotations__[1] = 2\n"
               "x: int = 5\n", gns, lns)
          self.assertEqual(lns["__annotations__"], {1: 2, 'x': int})
          with self.assertRaises(KeyError):
              gns['__annotations__']
  
      def test_var_annot_custom_maps(self):
          # tests with custom locals() and __annotations__
          ns = {'__annotations__': CNS()}
          exec('X: int; Z: str = "Z"; (w): complex = 1j', ns)
          self.assertEqual(ns['__annotations__']['x'], int)
          self.assertEqual(ns['__annotations__']['z'], str)
          with self.assertRaises(KeyError):
              ns['__annotations__']['w']
          nonloc_ns = {}
          class CNS2:
              def __init__(self):
                  self._dct = {}
              def __setitem__(self, item, value):
                  nonlocal nonloc_ns
                  self._dct[item] = value
                  nonloc_ns[item] = value
              def __getitem__(self, item):
                  return self._dct[item]
          exec('x: int = 1', {}, CNS2())
          self.assertEqual(nonloc_ns['__annotations__']['x'], int)
  
      def test_var_annot_refleak(self):
          # complex case: custom locals plus custom __annotations__
          # this was causing refleak
          cns = CNS()
          nonloc_ns = {'__annotations__': cns}
          class CNS2:
              def __init__(self):
                  self._dct = {'__annotations__': cns}
              def __setitem__(self, item, value):
                  nonlocal nonloc_ns
                  self._dct[item] = value
                  nonloc_ns[item] = value
              def __getitem__(self, item):
                  return self._dct[item]
          exec('X: str', {}, CNS2())
          self.assertEqual(nonloc_ns['__annotations__']['x'], str)
  
      def test_funcdef(self):
          ### [decorators] 'def' NAME parameters ['->' test] ':' suite
          ### decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
          ### decorators: decorator+
          ### parameters: '(' [typedargslist] ')'
          ### typedargslist: ((tfpdef ['=' test] ',')*
          ###                ('*' [tfpdef] (',' tfpdef ['=' test])* [',' '**' tfpdef] | '**' tfpdef)
          ###                | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
          ### tfpdef: NAME [':' test]
          ### varargslist: ((vfpdef ['=' test] ',')*
          ###              ('*' [vfpdef] (',' vfpdef ['=' test])*  [',' '**' vfpdef] | '**' vfpdef)
          ###              | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
          ### vfpdef: NAME
          def f1(): pass
          f1()
          f1(*())
          f1(*(), **{})
          def f2(one_argument): pass
          def f3(two, arguments): pass
          self.assertEqual(f2.__code__.co_varnames, ('one_argument',))
          self.assertEqual(f3.__code__.co_varnames, ('two', 'arguments'))
          def a1(one_arg,): pass
          def a2(two, args,): pass
          def v0(*rest): pass
          def v1(a, *rest): pass
          def v2(a, b, *rest): pass
  
          f1()
          f2(1)
          f2(1,)
          f3(1, 2)
          f3(1, 2,)
          v0()
          v0(1)
          v0(1,)
          v0(1,2)
          v0(1,2,3,4,5,6,7,8,9,0)
          v1(1)
          v1(1,)
          v1(1,2)
          v1(1,2,3)
          v1(1,2,3,4,5,6,7,8,9,0)
          v2(1,2)
          v2(1,2,3)
          v2(1,2,3,4)
          v2(1,2,3,4,5,6,7,8,9,0)
  
          def d01(a=1): pass
          d01()
          d01(1)
          d01(*(1,))
          d01(*[] or [2])
          d01(*() or (), *{} and (), **() or {})
          d01(**{'a':2})
          d01(**{'a':2} or {})
          def d11(a, b=1): pass
          d11(1)
          d11(1, 2)
          d11(1, **{'b':2})
          def d21(a, b, c=1): pass
          d21(1, 2)
          d21(1, 2, 3)
          d21(*(1, 2, 3))
          d21(1, *(2, 3))
          d21(1, 2, *(3,))
          d21(1, 2, **{'c':3})
          def d02(a=1, b=2): pass
          d02()
          d02(1)
          d02(1, 2)
          d02(*(1, 2))
          d02(1, *(2,))
          d02(1, **{'b':2})
          d02(**{'a': 1, 'b': 2})
          def d12(a, b=1, c=2): pass
          d12(1)
          d12(1, 2)
          d12(1, 2, 3)
          def d22(a, b, c=1, d=2): pass
          d22(1, 2)
          d22(1, 2, 3)
          d22(1, 2, 3, 4)
          def d01v(a=1, *rest): pass
          d01v()
          d01v(1)
          d01v(1, 2)
          d01v(*(1, 2, 3, 4))
          d01v(*(1,))
          d01v(**{'a':2})
          def d11v(a, b=1, *rest): pass
          d11v(1)
          d11v(1, 2)
          d11v(1, 2, 3)
          def d21v(a, b, c=1, *rest): pass
          d21v(1, 2)
          d21v(1, 2, 3)
          d21v(1, 2, 3, 4)
          d21v(*(1, 2, 3, 4))
          d21v(1, 2, **{'c': 3})
          def d02v(a=1, b=2, *rest): pass
          d02v()
          d02v(1)
          d02v(1, 2)
          d02v(1, 2, 3)
          d02v(1, *(2, 3, 4))
          d02v(**{'a': 1, 'b': 2})
          def d12v(a, b=1, c=2, *rest): pass
          d12v(1)
          d12v(1, 2)
          d12v(1, 2, 3)
          d12v(1, 2, 3, 4)
          d12v(*(1, 2, 3, 4))
          d12v(1, 2, *(3, 4, 5))
          d12v(1, *(2,), **{'c': 3})
          def d22v(a, b, c=1, d=2, *rest): pass
          d22v(1, 2)
          d22v(1, 2, 3)
          d22v(1, 2, 3, 4)
          d22v(1, 2, 3, 4, 5)
          d22v(*(1, 2, 3, 4))
          d22v(1, 2, *(3, 4, 5))
          d22v(1, *(2, 3), **{'d': 4})
  
          # keyword argument type tests
          try:
              str('x', **{b'foo':1 })
          except TypeError:
              pass
          else:
              self.fail('Bytes should not work as keyword argument names')
          # keyword only argument tests
          def pos0key1(*, key): return key
          pos0key1(key=100)
          def pos2key2(p1, p2, *, k1, k2=100): return p1,p2,k1,k2
          pos2key2(1, 2, k1=100)
          pos2key2(1, 2, k1=100, k2=200)
          pos2key2(1, 2, k2=100, k1=200)
          def pos2key2dict(p1, p2, *, k1=100, k2, **kwarg): return p1,p2,k1,k2,kwarg
          pos2key2dict(1,2,k2=100,tokwarg1=100,tokwarg2=200)
          pos2key2dict(1,2,tokwarg1=100,tokwarg2=200, k2=100)
  
          self.assertRaises(SyntaxError, eval, "def f(*): pass")
          self.assertRaises(SyntaxError, eval, "def f(*,): pass")
          self.assertRaises(SyntaxError, eval, "def f(*, **kwds): pass")
  
          # keyword arguments after *arglist
          def f(*args, **kwargs):
              return args, kwargs
          self.assertEqual(f(1, x=2, *[3, 4], y=5), ((1, 3, 4),
                                                      {'x':2, 'y':5}))
          self.assertEqual(f(1, *(2,3), 4), ((1, 2, 3, 4), {}))
          self.assertRaises(SyntaxError, eval, "f(1, x=2, *(3,4), x=5)")
          self.assertEqual(f(**{'eggs':'scrambled', 'spam':'fried'}),
                           ((), {'eggs':'scrambled', 'spam':'fried'}))
          self.assertEqual(f(spam='fried', **{'eggs':'scrambled'}),
                           ((), {'eggs':'scrambled', 'spam':'fried'}))
  
          # Check ast errors in *args and *kwargs
          check_syntax_error(self, "f(*g(1=2))")
          check_syntax_error(self, "f(**g(1=2))")
  
          # argument annotation tests
          def f(x) -> list: pass
          self.assertEqual(f.__annotations__, {'return': list})
          def f(x: int): pass
          self.assertEqual(f.__annotations__, {'x': int})
          def f(*x: str): pass
          self.assertEqual(f.__annotations__, {'x': str})
          def f(**x: float): pass
          self.assertEqual(f.__annotations__, {'x': float})
          def f(x, y: 1+2): pass
          self.assertEqual(f.__annotations__, {'y': 3})
          def f(a, b: 1, c: 2, d): pass
          self.assertEqual(f.__annotations__, {'b': 1, 'c': 2})
          def f(a, b: 1, c: 2, d, e: 3 = 4, f=5, *g: 6): pass
          self.assertEqual(f.__annotations__,
                           {'b': 1, 'c': 2, 'e': 3, 'g': 6})
          def f(a, b: 1, c: 2, d, e: 3 = 4, f=5, *g: 6, h: 7, i=8, j: 9 = 10,
                **k: 11) -> 12: pass
          self.assertEqual(f.__annotations__,
                           {'b': 1, 'c': 2, 'e': 3, 'g': 6, 'h': 7, 'j': 9,
                            'k': 11, 'return': 12})
          # Check for issue #20625 -- annotations mangling
          class Spam:
              def f(self, *, __kw: 1):
                  pass
          class Ham(Spam): pass
          self.assertEqual(Spam.f.__annotations__, {'_Spam__kw': 1})
          self.assertEqual(Ham.f.__annotations__, {'_Spam__kw': 1})
          # Check for SF Bug #1697248 - mixing decorators and a return annotation
          def null(x): return x
          @null
          def f(x) -> list: pass
          self.assertEqual(f.__annotations__, {'return': list})
  
          # test closures with a variety of opargs
          closure = 1
          def f(): return closure
          def f(x=1): return closure
          def f(*, k=1): return closure
          def f() -> int: return closure
  
          # Check trailing commas are permitted in funcdef argument list
          def f(a,): pass
          def f(*args,): pass
          def f(**kwds,): pass
          def f(a, *args,): pass
          def f(a, **kwds,): pass
          def f(*args, b,): pass
          def f(*, b,): pass
          def f(*args, **kwds,): pass
          def f(a, *args, b,): pass
          def f(a, *, b,): pass
          def f(a, *args, **kwds,): pass
          def f(*args, b, **kwds,): pass
          def f(*, b, **kwds,): pass
          def f(a, *args, b, **kwds,): pass
          def f(a, *, b, **kwds,): pass
  
      def test_lambdef(self):
          ### lambdef: 'lambda' [varargslist] ':' test
          l1 = lambda : 0
          self.assertEqual(l1(), 0)
          l2 = lambda : a[d] # XXX just testing the expression
          l3 = lambda : [2 < x for x in [-1, 3, 0]]
          self.assertEqual(l3(), [0, 1, 0])
          l4 = lambda x = lambda y = lambda z=1 : z : y() : x()
          self.assertEqual(l4(), 1)
          l5 = lambda x, y, z=2: x + y + z
          self.assertEqual(l5(1, 2), 5)
          self.assertEqual(l5(1, 2, 3), 6)
          check_syntax_error(self, "lambda x: x = 2")
          check_syntax_error(self, "lambda (None,): None")
          l6 = lambda x, y, *, k=20: x+y+k
          self.assertEqual(l6(1,2), 1+2+20)
          self.assertEqual(l6(1,2,k=10), 1+2+10)
  
          # check that trailing commas are permitted
          l10 = lambda a,: 0
          l11 = lambda *args,: 0
          l12 = lambda **kwds,: 0
          l13 = lambda a, *args,: 0
          l14 = lambda a, **kwds,: 0
          l15 = lambda *args, b,: 0
          l16 = lambda *, b,: 0
          l17 = lambda *args, **kwds,: 0
          l18 = lambda a, *args, b,: 0
          l19 = lambda a, *, b,: 0
          l20 = lambda a, *args, **kwds,: 0
          l21 = lambda *args, b, **kwds,: 0
          l22 = lambda *, b, **kwds,: 0
          l23 = lambda a, *args, b, **kwds,: 0
          l24 = lambda a, *, b, **kwds,: 0
  
  
      ### stmt: simple_stmt | compound_stmt
      # Tested below
  
      def test_simple_stmt(self):
          ### simple_stmt: small_stmt (';' small_stmt)* [';']
          x = 1; pass; del x
          def foo():
              # verify statements that end with semi-colons
              x = 1; pass; del x;
          foo()
  
      ### small_stmt: expr_stmt | pass_stmt | del_stmt | flow_stmt | import_stmt | global_stmt | access_stmt
      # Tested below
  
      def test_expr_stmt(self):
          # (exprlist '=')* exprlist
          1
          1, 2, 3
          x = 1
          x = 1, 2, 3
          x = y = z = 1, 2, 3
          x, y, z = 1, 2, 3
          abc = a, b, c = x, y, z = xyz = 1, 2, (3, 4)
  
          check_syntax_error(self, "x + 1 = 1")
          check_syntax_error(self, "a + 1 = b + 2")
  
      # Check the heuristic for print & exec covers significant cases
      # As well as placing some limits on false positives
      def test_former_statements_refer_to_builtins(self):
          keywords = "print", "exec"
          # Cases where we want the custom error
          cases = [
              "{} foo",
              "{} {{1:foo}}",
              "if 1: {} foo",
              "if 1: {} {{1:foo}}",
              "if 1:\n    {} foo",
              "if 1:\n    {} {{1:foo}}",
          ]
          for keyword in keywords:
              custom_msg = "call to '{}'".format(keyword)
              for case in cases:
                  source = case.format(keyword)
                  with self.subTest(source=source):
                      with self.assertRaisesRegex(SyntaxError, custom_msg):
                          exec(source)
                  source = source.replace("foo", "(foo.)")
                  # PyPy's parser also detects the same "Missing parentheses"
                  # if there are some parentheses later in the line
                  # (above, the cases that contain '{1:').
                  # CPython gives up in this case.
                  if check_impl_detail(pypy=True) and '{1:' in source:
                      expected = custom_msg
                  else:
                      expected = "invalid syntax"
                  with self.subTest(source=source):
                      with self.assertRaisesRegex(SyntaxError, expected):
                          exec(source)
  
      def test_del_stmt(self):
          # 'del' exprlist
          abc = [1,2,3]
          x, y, z = abc
          xyz = x, y, z
  
          del abc
          del x, y, (z, xyz)
  
      def test_pass_stmt(self):
          # 'pass'
          pass
  
      # flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt
      # Tested below
  
      def test_break_stmt(self):
          # 'break'
          while 1: break
  
      def test_continue_stmt(self):
          # 'continue'
          i = 1
          while i: i = 0; continue
  
          msg = ""
          while not msg:
              msg = "ok"
              try:
                  continue
                  msg = "continue failed to continue inside try"
              except:
                  msg = "continue inside try called except block"
          if msg != "ok":
              self.fail(msg)
  
          msg = ""
          while not msg:
              msg = "finally block not called"
              try:
                  continue
              finally:
                  msg = "ok"
          if msg != "ok":
              self.fail(msg)
  
      def test_break_continue_loop(self):
          # This test warrants an explanation. It is a test specifically for SF bugs
          # #463359 and #462937. The bug is that a 'break' statement executed or
          # exception raised inside a try/except inside a loop, *after* a continue
          # statement has been executed in that loop, will cause the wrong number of
          # arguments to be popped off the stack and the instruction pointer reset to
          # a very small number (usually 0.) Because of this, the following test
          # *must* written as a function, and the tracking vars *must* be function
          # arguments with default values. Otherwise, the test will loop and loop.
  
          def test_inner(extra_burning_oil = 1, count=0):
              big_hippo = 2
              while big_hippo:
                  count += 1
                  try:
                      if extra_burning_oil and big_hippo == 1:
                          extra_burning_oil -= 1
                          break
                      big_hippo -= 1
                      continue
                  except:
                      raise
              if count > 2 or big_hippo != 1:
                  self.fail("continue then break in try/except in loop broken!")
          test_inner()
  
      def test_return(self):
          # 'return' [testlist]
          def g1(): return
          def g2(): return 1
          g1()
          x = g2()
          check_syntax_error(self, "class foo:return 1")
  
      def test_break_in_finally(self):
          count = 0
          while count < 2:
              count += 1
              try:
                  pass
              finally:
                  break
          self.assertEqual(count, 1)
  
          count = 0
          while count < 2:
              count += 1
              try:
                  continue
              finally:
                  break
          self.assertEqual(count, 1)
  
          count = 0
          while count < 2:
              count += 1
              try:
                  1/0
              finally:
                  break
          self.assertEqual(count, 1)
  
          for count in [0, 1]:
              self.assertEqual(count, 0)
              try:
                  pass
              finally:
                  break
          self.assertEqual(count, 0)
  
          for count in [0, 1]:
              self.assertEqual(count, 0)
              try:
                  continue
              finally:
                  break
          self.assertEqual(count, 0)
  
          for count in [0, 1]:
              self.assertEqual(count, 0)
              try:
                  1/0
              finally:
                  break
          self.assertEqual(count, 0)
  
      def test_return_in_finally(self):
          def g1():
              try:
                  pass
              finally:
                  return 1
          self.assertEqual(g1(), 1)
  
          def g2():
              try:
                  return 2
              finally:
                  return 3
          self.assertEqual(g2(), 3)
  
          def g3():
              try:
                  1/0
              finally:
                  return 4
          self.assertEqual(g3(), 4)
  
      def test_yield(self):
          # Allowed as standalone statement
          def g(): yield 1
          def g(): yield from ()
          # Allowed as RHS of assignment
          def g(): x = yield 1
          def g(): x = yield from ()
          # Ordinary yield accepts implicit tuples
          def g(): yield 1, 1
          def g(): x = yield 1, 1
          # 'yield from' does not
          check_syntax_error(self, "def g(): yield from (), 1")
          check_syntax_error(self, "def g(): x = yield from (), 1")
          # Requires parentheses as subexpression
          def g(): 1, (yield 1)
          def g(): 1, (yield from ())
          check_syntax_error(self, "def g(): 1, yield 1")
          check_syntax_error(self, "def g(): 1, yield from ()")
          # Requires parentheses as call argument
          def g(): f((yield 1))
          def g(): f((yield 1), 1)
          def g(): f((yield from ()))
          def g(): f((yield from ()), 1)
          check_syntax_error(self, "def g(): f(yield 1)")
          check_syntax_error(self, "def g(): f(yield 1, 1)")
          check_syntax_error(self, "def g(): f(yield from ())")
          check_syntax_error(self, "def g(): f(yield from (), 1)")
          # Not allowed at top level
          check_syntax_error(self, "yield")
          check_syntax_error(self, "yield from")
          # Not allowed at class scope
          check_syntax_error(self, "class foo:yield 1")
          check_syntax_error(self, "class foo:yield from ()")
          # Check annotation refleak on SyntaxError
          check_syntax_error(self, "def g(a:(yield)): pass")
  
      def test_yield_in_comprehensions(self):
          # Check yield in comprehensions
          def g(): [x for x in [(yield 1)]]
          def g(): [x for x in [(yield from ())]]
  
          def check(code, warntext):
              with self.assertWarnsRegex(DeprecationWarning, warntext):
                  compile(code, '<test string>', 'exec')
              import warnings
              with warnings.catch_warnings():
                  warnings.filterwarnings('error', category=DeprecationWarning)
                  with self.assertRaisesRegex(SyntaxError, warntext):
                      compile(code, '<test string>', 'exec')
  
          check("def g(): [(yield x) for x in ()]",
                "'yield' inside list comprehension")
          check("def g(): [x for x in () if not (yield x)]",
                "'yield' inside list comprehension")
          check("def g(): [y for x in () for y in [(yield x)]]",
                "'yield' inside list comprehension")
          check("def g(): {(yield x) for x in ()}",
                "'yield' inside set comprehension")
          check("def g(): {(yield x): x for x in ()}",
                "'yield' inside dict comprehension")
          check("def g(): {x: (yield x) for x in ()}",
                "'yield' inside dict comprehension")
          check("def g(): ((yield x) for x in ())",
                "'yield' inside generator expression")
          check("def g(): [(yield from x) for x in ()]",
                "'yield' inside list comprehension")
          check("class C: [(yield x) for x in ()]",
                "'yield' inside list comprehension")
          check("[(yield x) for x in ()]",
                "'yield' inside list comprehension")
  
      def test_raise(self):
          # 'raise' test [',' test]
          try: raise RuntimeError('just testing')
          except RuntimeError: pass
          try: raise KeyboardInterrupt
          except KeyboardInterrupt: pass
  
      def test_import(self):
          # 'import' dotted_as_names
          import sys
          import time, sys
          # 'from' dotted_name 'import' ('*' | '(' import_as_names ')' | import_as_names)
          from time import time
          from time import (time)
          # not testable inside a function, but already done at top of the module
          # from sys import *
          from sys import path, argv
          from sys import (path, argv)
          from sys import (path, argv,)
  
      def test_global(self):
          # 'global' NAME (',' NAME)*
          global a
          global a, b
          global one, two, three, four, five, six, seven, eight, nine, ten
  
      def test_nonlocal(self):
          # 'nonlocal' NAME (',' NAME)*
          x = 0
          y = 0
          def f():
              nonlocal x
              nonlocal x, y
  
      def test_assert(self):
          # assertTruestmt: 'assert' test [',' test]
          assert 1
          assert 1, 1
          assert lambda x:x
          assert 1, lambda x:x+1
  
          try:
              assert True
          except AssertionError as e:
              self.fail("'assert True' should not have raised an AssertionError")
  
          try:
              assert True, 'this should always pass'
          except AssertionError as e:
              self.fail("'assert True, msg' should not have "
                        "raised an AssertionError")
  
      # these tests fail if python is run with -O, so check __debug__
      @unittest.skipUnless(__debug__, "Won't work if __debug__ is False")
      def testAssert2(self):
          try:
              assert 0, "msg"
          except AssertionError as e:
              self.assertEqual(e.args[0], "msg")
          else:
              self.fail("AssertionError not raised by assert 0")
  
          try:
              assert False
          except AssertionError as e:
              self.assertEqual(len(e.args), 0)
          else:
              self.fail("AssertionError not raised by 'assert False'")
  
  
      ### compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | funcdef | classdef
      # Tested below
  
      def test_if(self):
          # 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
          if 1: pass
          if 1: pass
          else: pass
          if 0: pass
          elif 0: pass
          if 0: pass
          elif 0: pass
          elif 0: pass
          elif 0: pass
          else: pass
  
      def test_while(self):
          # 'while' test ':' suite ['else' ':' suite]
          while 0: pass
          while 0: pass
          else: pass
  
          # Issue1920: "while 0" is optimized away,
          # ensure that the "else" clause is still present.
          x = 0
          while 0:
              x = 1
          else:
              x = 2
          self.assertEqual(x, 2)
  
      def test_for(self):
          # 'for' exprlist 'in' exprlist ':' suite ['else' ':' suite]
          for i in 1, 2, 3: pass
          for i, j, k in (): pass
          else: pass
          class Squares:
              def __init__(self, max):
                  self.max = max
                  self.sofar = []
              def __len__(self): return len(self.sofar)
              def __getitem__(self, i):
                  if not 0 <= i < self.max: raise IndexError
                  n = len(self.sofar)
                  while n <= i:
                      self.sofar.append(n*n)
                      n = n+1
                  return self.sofar[i]
          n = 0
          for x in Squares(10): n = n+x
          if n != 285:
              self.fail('for over growing sequence')
  
          result = []
          for x, in [(1,), (2,), (3,)]:
              result.append(x)
          self.assertEqual(result, [1, 2, 3])
  
      def test_try(self):
          ### try_stmt: 'try' ':' suite (except_clause ':' suite)+ ['else' ':' suite]
          ###         | 'try' ':' suite 'finally' ':' suite
          ### except_clause: 'except' [expr ['as' expr]]
          try:
              1/0
          except ZeroDivisionError:
              pass
          else:
              pass
          try: 1/0
          except EOFError: pass
          except TypeError as msg: pass
          except: pass
          else: pass
          try: 1/0
          except (EOFError, TypeError, ZeroDivisionError): pass
          try: 1/0
          except (EOFError, TypeError, ZeroDivisionError) as msg: pass
          try: pass
          finally: pass
  
      def test_suite(self):
          # simple_stmt | NEWLINE INDENT NEWLINE* (stmt NEWLINE*)+ DEDENT
          if 1: pass
          if 1:
              pass
          if 1:
              #
              #
              #
              pass
              pass
              #
              pass
              #
  
      def test_test(self):
          ### and_test ('or' and_test)*
          ### and_test: not_test ('and' not_test)*
          ### not_test: 'not' not_test | comparison
          if not 1: pass
          if 1 and 1: pass
          if 1 or 1: pass
          if not not not 1: pass
          if not 1 and 1 and 1: pass
          if 1 and 1 or 1 and 1 and 1 or not 1 and 1: pass
  
      def test_comparison(self):
          ### comparison: expr (comp_op expr)*
          ### comp_op: '<'|'>'|'=='|'>='|'<='|'!='|'in'|'not' 'in'|'is'|'is' 'not'
          if 1: pass
          x = (1 == 1)
          if 1 == 1: pass
          if 1 != 1: pass
          if 1 < 1: pass
          if 1 > 1: pass
          if 1 <= 1: pass
          if 1 >= 1: pass
          if 1 is 1: pass
          if 1 is not 1: pass
          if 1 in (): pass
          if 1 not in (): pass
          if 1 < 1 > 1 == 1 >= 1 <= 1 != 1 in 1 not in 1 is 1 is not 1: pass
  
      def test_binary_mask_ops(self):
          x = 1 & 1
          x = 1 ^ 1
          x = 1 | 1
  
      def test_shift_ops(self):
          x = 1 << 1
          x = 1 >> 1
          x = 1 << 1 >> 1
  
      def test_additive_ops(self):
          x = 1
          x = 1 + 1
          x = 1 - 1 - 1
          x = 1 - 1 + 1 - 1 + 1
  
      def test_multiplicative_ops(self):
          x = 1 * 1
          x = 1 / 1
          x = 1 % 1
          x = 1 / 1 * 1 % 1
  
      def test_unary_ops(self):
          x = +1
          x = -1
          x = ~1
          x = ~1 ^ 1 & 1 | 1 & 1 ^ -1
          x = -1*1/1 + 1*1 - ---1*1
  
      def test_selectors(self):
          ### trailer: '(' [testlist] ')' | '[' subscript ']' | '.' NAME
          ### subscript: expr | [expr] ':' [expr]
  
          import sys, time
          c = sys.path[0]
          x = time.time()
          x = sys.modules['time'].time()
          a = '01234'
          c = a[0]
          c = a[-1]
          s = a[0:5]
          s = a[:5]
          s = a[0:]
          s = a[:]
          s = a[-5:]
          s = a[:-1]
          s = a[-4:-3]
          # A rough test of SF bug 1333982.  http://python.org/sf/1333982
          # The testing here is fairly incomplete.
          # Test cases should include: commas with 1 and 2 colons
          d = {}
          d[1] = 1
          d[1,] = 2
          d[1,2] = 3
          d[1,2,3] = 4
          L = list(d)
          L.sort(key=lambda x: (type(x).__name__, x))
          self.assertEqual(str(L), '[1, (1,), (1, 2), (1, 2, 3)]')
  
      def test_atoms(self):
          ### atom: '(' [testlist] ')' | '[' [testlist] ']' | '{' [dictsetmaker] '}' | NAME | NUMBER | STRING
          ### dictsetmaker: (test ':' test (',' test ':' test)* [',']) | (test (',' test)* [','])
  
          x = (1)
          x = (1 or 2 or 3)
          x = (1 or 2 or 3, 2, 3)
  
          x = []
          x = [1]
          x = [1 or 2 or 3]
          x = [1 or 2 or 3, 2, 3]
          x = []
  
          x = {}
          x = {'one': 1}
          x = {'one': 1,}
          x = {'one' or 'two': 1 or 2}
          x = {'one': 1, 'two': 2}
          x = {'one': 1, 'two': 2,}
          x = {'one': 1, 'two': 2, 'three': 3, 'four': 4, 'five': 5, 'six': 6}
  
          x = {'one'}
          x = {'one', 1,}
          x = {'one', 'two', 'three'}
          x = {2, 3, 4,}
  
          x = x
          x = 'x'
          x = 123
  
      ### exprlist: expr (',' expr)* [',']
      ### testlist: test (',' test)* [',']
      # These have been exercised enough above
  
      def test_classdef(self):
          # 'class' NAME ['(' [testlist] ')'] ':' suite
          class B: pass
          class B2(): pass
          class C1(B): pass
          class C2(B): pass
          class D(C1, C2, B): pass
          class C:
              def meth1(self): pass
              def meth2(self, arg): pass
              def meth3(self, a1, a2): pass
  
          # decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
          # decorators: decorator+
          # decorated: decorators (classdef | funcdef)
          def class_decorator(x): return x
          @class_decorator
          class G: pass
  
      def test_dictcomps(self):
          # dictorsetmaker: ( (test ':' test (comp_for |
          #                                   (',' test ':' test)* [','])) |
          #                   (test (comp_for | (',' test)* [','])) )
          nums = [1, 2, 3]
          self.assertEqual({i:i+1 for i in nums}, {1: 2, 2: 3, 3: 4})
  
      def test_listcomps(self):
          # list comprehension tests
          nums = [1, 2, 3, 4, 5]
          strs = ["Apple", "Banana", "Coconut"]
          spcs = ["  Apple", " Banana ", "Coco  nut  "]
  
          self.assertEqual([s.strip() for s in spcs], ['Apple', 'Banana', 'Coco  nut'])
          self.assertEqual([3 * x for x in nums], [3, 6, 9, 12, 15])
          self.assertEqual([x for x in nums if x > 2], [3, 4, 5])
          self.assertEqual([(i, s) for i in nums for s in strs],
                           [(1, 'Apple'), (1, 'Banana'), (1, 'Coconut'),
                            (2, 'Apple'), (2, 'Banana'), (2, 'Coconut'),
                            (3, 'Apple'), (3, 'Banana'), (3, 'Coconut'),
                            (4, 'Apple'), (4, 'Banana'), (4, 'Coconut'),
                            (5, 'Apple'), (5, 'Banana'), (5, 'Coconut')])
          self.assertEqual([(i, s) for i in nums for s in [f for f in strs if "n" in f]],
                           [(1, 'Banana'), (1, 'Coconut'), (2, 'Banana'), (2, 'Coconut'),
                            (3, 'Banana'), (3, 'Coconut'), (4, 'Banana'), (4, 'Coconut'),
                            (5, 'Banana'), (5, 'Coconut')])
          self.assertEqual([(lambda a:[a**i for i in range(a+1)])(j) for j in range(5)],
                           [[1], [1, 1], [1, 2, 4], [1, 3, 9, 27], [1, 4, 16, 64, 256]])
  
          def test_in_func(l):
              return [0 < x < 3 for x in l if x > 2]
  
          self.assertEqual(test_in_func(nums), [False, False, False])
  
          def test_nested_front():
              self.assertEqual([[y for y in [x, x + 1]] for x in [1,3,5]],
                               [[1, 2], [3, 4], [5, 6]])
  
          test_nested_front()
  
          check_syntax_error(self, "[i, s for i in nums for s in strs]")
          check_syntax_error(self, "[x if y]")
  
          suppliers = [
            (1, "Boeing"),
            (2, "Ford"),
            (3, "Macdonalds")
          ]
  
          parts = [
            (10, "Airliner"),
            (20, "Engine"),
            (30, "Cheeseburger")
          ]
  
          suppart = [
            (1, 10), (1, 20), (2, 20), (3, 30)
          ]
  
          x = [
            (sname, pname)
              for (sno, sname) in suppliers
                for (pno, pname) in parts
                  for (sp_sno, sp_pno) in suppart
                    if sno == sp_sno and pno == sp_pno
          ]
  
          self.assertEqual(x, [('Boeing', 'Airliner'), ('Boeing', 'Engine'), ('Ford', 'Engine'),
                               ('Macdonalds', 'Cheeseburger')])
  
      def test_genexps(self):
          # generator expression tests
          g = ([x for x in range(10)] for x in range(1))
          self.assertEqual(next(g), [x for x in range(10)])
          try:
              next(g)
              self.fail('should produce StopIteration exception')
          except StopIteration:
              pass
  
          a = 1
          try:
              g = (a for d in a)
              next(g)
              self.fail('should produce TypeError')
          except TypeError:
              pass
  
          self.assertEqual(list((x, y) for x in 'abcd' for y in 'abcd'), [(x, y) for x in 'abcd' for y in 'abcd'])
          self.assertEqual(list((x, y) for x in 'ab' for y in 'xy'), [(x, y) for x in 'ab' for y in 'xy'])
  
          a = [x for x in range(10)]
          b = (x for x in (y for y in a))
          self.assertEqual(sum(b), sum([x for x in range(10)]))
  
          self.assertEqual(sum(x**2 for x in range(10)), sum([x**2 for x in range(10)]))
          self.assertEqual(sum(x*x for x in range(10) if x%2), sum([x*x for x in range(10) if x%2]))
          self.assertEqual(sum(x for x in (y for y in range(10))), sum([x for x in range(10)]))
          self.assertEqual(sum(x for x in (y for y in (z for z in range(10)))), sum([x for x in range(10)]))
          self.assertEqual(sum(x for x in [y for y in (z for z in range(10))]), sum([x for x in range(10)]))
          self.assertEqual(sum(x for x in (y for y in (z for z in range(10) if True)) if True), sum([x for x in range(10)]))
          self.assertEqual(sum(x for x in (y for y in (z for z in range(10) if True) if False) if True), 0)
          check_syntax_error(self, "foo(x for x in range(10), 100)")
          check_syntax_error(self, "foo(100, x for x in range(10))")
  
      def test_comprehension_specials(self):
          # test for outmost iterable precomputation
          x = 10; g = (i for i in range(x)); x = 5
          self.assertEqual(len(list(g)), 10)
  
          # This should hold, since we're only precomputing outmost iterable.
          x = 10; t = False; g = ((i,j) for i in range(x) if t for j in range(x))
          x = 5; t = True;
          self.assertEqual([(i,j) for i in range(10) for j in range(5)], list(g))
  
          # Grammar allows multiple adjacent 'if's in listcomps and genexps,
          # even though it's silly. Make sure it works (ifelse broke this.)
          self.assertEqual([ x for x in range(10) if x % 2 if x % 3 ], [1, 5, 7])
          self.assertEqual(list(x for x in range(10) if x % 2 if x % 3), [1, 5, 7])
  
          # verify unpacking single element tuples in listcomp/genexp.
          self.assertEqual([x for x, in [(4,), (5,), (6,)]], [4, 5, 6])
          self.assertEqual(list(x for x, in [(7,), (8,), (9,)]), [7, 8, 9])
  
      def test_with_statement(self):
          class manager(object):
              def __enter__(self):
                  return (1, 2)
              def __exit__(self, *args):
                  pass
  
          with manager():
              pass
          with manager() as x:
              pass
          with manager() as (x, y):
              pass
          with manager(), manager():
              pass
          with manager() as x, manager() as y:
              pass
          with manager() as x, manager():
              pass
  
      def test_if_else_expr(self):
          # Test ifelse expressions in various cases
          def _checkeval(msg, ret):
              "helper to check that evaluation of expressions is done correctly"
              print(msg)
              return ret
  
          # the next line is not allowed anymore
          #self.assertEqual([ x() for x in lambda: True, lambda: False if x() ], [True])
          self.assertEqual([ x() for x in (lambda: True, lambda: False) if x() ], [True])
          self.assertEqual([ x(False) for x in (lambda x: False if x else True, lambda x: True if x else False) if x(False) ], [True])
          self.assertEqual((5 if 1 else _checkeval("check 1", 0)), 5)
          self.assertEqual((_checkeval("check 2", 0) if 0 else 5), 5)
          self.assertEqual((5 and 6 if 0 else 1), 1)
          self.assertEqual(((5 and 6) if 0 else 1), 1)
          self.assertEqual((5 and (6 if 1 else 1)), 6)
          self.assertEqual((0 or _checkeval("check 3", 2) if 0 else 3), 3)
          self.assertEqual((1 or _checkeval("check 4", 2) if 1 else _checkeval("check 5", 3)), 1)
          self.assertEqual((0 or 5 if 1 else _checkeval("check 6", 3)), 5)
          self.assertEqual((not 5 if 1 else 1), False)
          self.assertEqual((not 5 if 0 else 1), 1)
          self.assertEqual((6 + 1 if 1 else 2), 7)
          self.assertEqual((6 - 1 if 1 else 2), 5)
          self.assertEqual((6 * 2 if 1 else 4), 12)
          self.assertEqual((6 / 2 if 1 else 3), 3)
          self.assertEqual((6 < 4 if 0 else 2), 2)
  
      def test_paren_evaluation(self):
          self.assertEqual(16 // (4 // 2), 8)
          self.assertEqual((16 // 4) // 2, 2)
          self.assertEqual(16 // 4 // 2, 2)
          self.assertTrue(False is (2 is 3))
          self.assertFalse((False is 2) is 3)
          self.assertFalse(False is 2 is 3)
  
      def test_matrix_mul(self):
          # This is not intended to be a comprehensive test, rather just to be few
          # samples of the @ operator in test_grammar.py.
          class M:
              def __matmul__(self, o):
                  return 4
              def __imatmul__(self, o):
                  self.other = o
                  return self
          m = M()
          self.assertEqual(m @ m, 4)
          m @= 42
          self.assertEqual(m.other, 42)
  
      def test_async_await(self):
          async def test():
              def sum():
                  pass
              if 1:
                  await someobj()
  
          self.assertEqual(test.__name__, 'test')
          self.assertTrue(bool(test.__code__.co_flags & inspect.CO_COROUTINE))
  
          def decorator(func):
              setattr(func, '_marked', True)
              return func
  
          @decorator
          async def test2():
              return 22
          self.assertTrue(test2._marked)
          self.assertEqual(test2.__name__, 'test2')
          self.assertTrue(bool(test2.__code__.co_flags & inspect.CO_COROUTINE))
  
      def test_async_for(self):
          class Done(Exception): pass
  
          class AIter:
              def __aiter__(self):
                  return self
              async def __anext__(self):
                  raise StopAsyncIteration
  
          async def foo():
              async for i in AIter():
                  pass
              async for i, j in AIter():
                  pass
              async for i in AIter():
                  pass
              else:
                  pass
              raise Done
  
          with self.assertRaises(Done):
              foo().send(None)
  
      def test_async_with(self):
          class Done(Exception): pass
  
          class manager:
              async def __aenter__(self):
                  return (1, 2)
              async def __aexit__(self, *exc):
                  return False
  
          async def foo():
              async with manager():
                  pass
              async with manager() as x:
                  pass
              async with manager() as (x, y):
                  pass
              async with manager(), manager():
                  pass
              async with manager() as x, manager() as y:
                  pass
              async with manager() as x, manager():
                  pass
              raise Done
  
          with self.assertRaises(Done):
              foo().send(None)
  
  
  if __name__ == '__main__':
      unittest.main()
  