# Copyright 2007 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. # Note: each test is run with Python and C versions of ABCMeta. Except for # test_ABC_helper(), which assures that abc.ABC is an instance of abc.ABCMeta. """Unit tests for abc.py.""" import unittest import abc import _py_abc from inspect import isabstract def test_factory(abc_ABCMeta, abc_get_cache_token): class TestLegacyAPI(unittest.TestCase): def test_abstractproperty_basics(self): @abc.abstractproperty def foo(self): pass self.assertTrue(foo.__isabstractmethod__) def bar(self): pass self.assertFalse(hasattr(bar, "__isabstractmethod__")) class C(metaclass=abc_ABCMeta): @abc.abstractproperty def foo(self): return 3 self.assertRaises(TypeError, C) class D(C): @property def foo(self): return super().foo self.assertEqual(D().foo, 3) self.assertFalse(getattr(D.foo, "__isabstractmethod__", False)) def test_abstractclassmethod_basics(self): @abc.abstractclassmethod def foo(cls): pass self.assertTrue(foo.__isabstractmethod__) @classmethod def bar(cls): pass self.assertFalse(getattr(bar, "__isabstractmethod__", False)) class C(metaclass=abc_ABCMeta): @abc.abstractclassmethod def foo(cls): return cls.__name__ self.assertRaises(TypeError, C) class D(C): @classmethod def foo(cls): return super().foo() self.assertEqual(D.foo(), 'D') self.assertEqual(D().foo(), 'D') def test_abstractstaticmethod_basics(self): @abc.abstractstaticmethod def foo(): pass self.assertTrue(foo.__isabstractmethod__) @staticmethod def bar(): pass self.assertFalse(getattr(bar, "__isabstractmethod__", False)) class C(metaclass=abc_ABCMeta): @abc.abstractstaticmethod def foo(): return 3 self.assertRaises(TypeError, C) class D(C): @staticmethod def foo(): return 4 self.assertEqual(D.foo(), 4) self.assertEqual(D().foo(), 4) class TestABC(unittest.TestCase): def test_ABC_helper(self): # create an ABC using the helper class and perform basic checks class C(abc.ABC): @classmethod @abc.abstractmethod def foo(cls): return cls.__name__ self.assertEqual(type(C), abc.ABCMeta) self.assertRaises(TypeError, C) class D(C): @classmethod def foo(cls): return super().foo() self.assertEqual(D.foo(), 'D') def test_abstractmethod_basics(self): @abc.abstractmethod def foo(self): pass self.assertTrue(foo.__isabstractmethod__) def bar(self): pass self.assertFalse(hasattr(bar, "__isabstractmethod__")) def test_abstractproperty_basics(self): @property @abc.abstractmethod def foo(self): pass self.assertTrue(foo.__isabstractmethod__) def bar(self): pass self.assertFalse(getattr(bar, "__isabstractmethod__", False)) class C(metaclass=abc_ABCMeta): @property @abc.abstractmethod def foo(self): return 3 self.assertRaises(TypeError, C) class D(C): @C.foo.getter def foo(self): return super().foo self.assertEqual(D().foo, 3) def test_abstractclassmethod_basics(self): @classmethod @abc.abstractmethod def foo(cls): pass self.assertTrue(foo.__isabstractmethod__) @classmethod def bar(cls): pass self.assertFalse(getattr(bar, "__isabstractmethod__", False)) class C(metaclass=abc_ABCMeta): @classmethod @abc.abstractmethod def foo(cls): return cls.__name__ self.assertRaises(TypeError, C) class D(C): @classmethod def foo(cls): return super().foo() self.assertEqual(D.foo(), 'D') self.assertEqual(D().foo(), 'D') def test_abstractstaticmethod_basics(self): @staticmethod @abc.abstractmethod def foo(): pass self.assertTrue(foo.__isabstractmethod__) @staticmethod def bar(): pass self.assertFalse(getattr(bar, "__isabstractmethod__", False)) class C(metaclass=abc_ABCMeta): @staticmethod @abc.abstractmethod def foo(): return 3 self.assertRaises(TypeError, C) class D(C): @staticmethod def foo(): return 4 self.assertEqual(D.foo(), 4) self.assertEqual(D().foo(), 4) def test_abstractmethod_integration(self): for abstractthing in [abc.abstractmethod, abc.abstractproperty, abc.abstractclassmethod, abc.abstractstaticmethod]: class C(metaclass=abc_ABCMeta): @abstractthing def foo(self): pass # abstract def bar(self): pass # concrete self.assertEqual(C.__abstractmethods__, {"foo"}) self.assertRaises(TypeError, C) # because foo is abstract self.assertTrue(isabstract(C)) class D(C): def bar(self): pass # concrete override of concrete self.assertEqual(D.__abstractmethods__, {"foo"}) self.assertRaises(TypeError, D) # because foo is still abstract self.assertTrue(isabstract(D)) class E(D): def foo(self): pass self.assertEqual(E.__abstractmethods__, set()) E() # now foo is concrete, too self.assertFalse(isabstract(E)) class F(E): @abstractthing def bar(self): pass # abstract override of concrete self.assertEqual(F.__abstractmethods__, {"bar"}) self.assertRaises(TypeError, F) # because bar is abstract now self.assertTrue(isabstract(F)) def test_descriptors_with_abstractmethod(self): class C(metaclass=abc_ABCMeta): @property @abc.abstractmethod def foo(self): return 3 @foo.setter @abc.abstractmethod def foo(self, val): pass self.assertRaises(TypeError, C) class D(C): @C.foo.getter def foo(self): return super().foo self.assertRaises(TypeError, D) class E(D): @D.foo.setter def foo(self, val): pass self.assertEqual(E().foo, 3) # check that the property's __isabstractmethod__ descriptor does the # right thing when presented with a value that fails truth testing: class NotBool(object): def __bool__(self): raise ValueError() __len__ = __bool__ with self.assertRaises(ValueError): class F(C): def bar(self): pass bar.__isabstractmethod__ = NotBool() foo = property(bar) def test_customdescriptors_with_abstractmethod(self): class Descriptor: def __init__(self, fget, fset=None): self._fget = fget self._fset = fset def getter(self, callable): return Descriptor(callable, self._fget) def setter(self, callable): return Descriptor(self._fget, callable) @property def __isabstractmethod__(self): return (getattr(self._fget, '__isabstractmethod__', False) or getattr(self._fset, '__isabstractmethod__', False)) class C(metaclass=abc_ABCMeta): @Descriptor @abc.abstractmethod def foo(self): return 3 @foo.setter @abc.abstractmethod def foo(self, val): pass self.assertRaises(TypeError, C) class D(C): @C.foo.getter def foo(self): return super().foo self.assertRaises(TypeError, D) class E(D): @D.foo.setter def foo(self, val): pass self.assertFalse(E.foo.__isabstractmethod__) def test_metaclass_abc(self): # Metaclasses can be ABCs, too. class A(metaclass=abc_ABCMeta): @abc.abstractmethod def x(self): pass self.assertEqual(A.__abstractmethods__, {"x"}) class meta(type, A): def x(self): return 1 class C(metaclass=meta): pass def test_registration_basics(self): class A(metaclass=abc_ABCMeta): pass class B(object): pass b = B() self.assertFalse(issubclass(B, A)) self.assertFalse(issubclass(B, (A,))) self.assertNotIsInstance(b, A) self.assertNotIsInstance(b, (A,)) B1 = A.register(B) self.assertTrue(issubclass(B, A)) self.assertTrue(issubclass(B, (A,))) self.assertIsInstance(b, A) self.assertIsInstance(b, (A,)) self.assertIs(B1, B) class C(B): pass c = C() self.assertTrue(issubclass(C, A)) self.assertTrue(issubclass(C, (A,))) self.assertIsInstance(c, A) self.assertIsInstance(c, (A,)) def test_register_as_class_deco(self): class A(metaclass=abc_ABCMeta): pass @A.register class B(object): pass b = B() self.assertTrue(issubclass(B, A)) self.assertTrue(issubclass(B, (A,))) self.assertIsInstance(b, A) self.assertIsInstance(b, (A,)) @A.register class C(B): pass c = C() self.assertTrue(issubclass(C, A)) self.assertTrue(issubclass(C, (A,))) self.assertIsInstance(c, A) self.assertIsInstance(c, (A,)) self.assertIs(C, A.register(C)) def test_isinstance_invalidation(self): class A(metaclass=abc_ABCMeta): pass class B: pass b = B() self.assertFalse(isinstance(b, A)) self.assertFalse(isinstance(b, (A,))) token_old = abc_get_cache_token() A.register(B) token_new = abc_get_cache_token() self.assertNotEqual(token_old, token_new) self.assertTrue(isinstance(b, A)) self.assertTrue(isinstance(b, (A,))) def test_registration_builtins(self): class A(metaclass=abc_ABCMeta): pass A.register(int) self.assertIsInstance(42, A) self.assertIsInstance(42, (A,)) self.assertTrue(issubclass(int, A)) self.assertTrue(issubclass(int, (A,))) class B(A): pass B.register(str) class C(str): pass self.assertIsInstance("", A) self.assertIsInstance("", (A,)) self.assertTrue(issubclass(str, A)) self.assertTrue(issubclass(str, (A,))) self.assertTrue(issubclass(C, A)) self.assertTrue(issubclass(C, (A,))) def test_registration_edge_cases(self): class A(metaclass=abc_ABCMeta): pass A.register(A) # should pass silently class A1(A): pass self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed class B(object): pass A1.register(B) # ok A1.register(B) # should pass silently class C(A): pass A.register(C) # should pass silently self.assertRaises(RuntimeError, C.register, A) # cycles not allowed C.register(B) # ok def test_register_non_class(self): class A(metaclass=abc_ABCMeta): pass self.assertRaisesRegex(TypeError, "Can only register classes", A.register, 4) def test_registration_transitiveness(self): class A(metaclass=abc_ABCMeta): pass self.assertTrue(issubclass(A, A)) self.assertTrue(issubclass(A, (A,))) class B(metaclass=abc_ABCMeta): pass self.assertFalse(issubclass(A, B)) self.assertFalse(issubclass(A, (B,))) self.assertFalse(issubclass(B, A)) self.assertFalse(issubclass(B, (A,))) class C(metaclass=abc_ABCMeta): pass A.register(B) class B1(B): pass self.assertTrue(issubclass(B1, A)) self.assertTrue(issubclass(B1, (A,))) class C1(C): pass B1.register(C1) self.assertFalse(issubclass(C, B)) self.assertFalse(issubclass(C, (B,))) self.assertFalse(issubclass(C, B1)) self.assertFalse(issubclass(C, (B1,))) self.assertTrue(issubclass(C1, A)) self.assertTrue(issubclass(C1, (A,))) self.assertTrue(issubclass(C1, B)) self.assertTrue(issubclass(C1, (B,))) self.assertTrue(issubclass(C1, B1)) self.assertTrue(issubclass(C1, (B1,))) C1.register(int) class MyInt(int): pass self.assertTrue(issubclass(MyInt, A)) self.assertTrue(issubclass(MyInt, (A,))) self.assertIsInstance(42, A) self.assertIsInstance(42, (A,)) def test_issubclass_bad_arguments(self): class A(metaclass=abc_ABCMeta): pass with self.assertRaises(TypeError): issubclass({}, A) # unhashable with self.assertRaises(TypeError): issubclass(42, A) # No __mro__ # Python version supports any iterable as __mro__. # But it's implementation detail and don't emulate it in C version. class C: __mro__ = 42 # __mro__ is not tuple with self.assertRaises(TypeError): issubclass(C(), A) # bpo-34441: Check that issubclass() doesn't crash on bogus # classes. bogus_subclasses = [ None, lambda x: [], lambda: 42, lambda: [42], ] for i, func in enumerate(bogus_subclasses): class S(metaclass=abc_ABCMeta): __subclasses__ = func with self.subTest(i=i): with self.assertRaises(TypeError): issubclass(int, S) # Also check that issubclass() propagates exceptions raised by # __subclasses__. exc_msg = "exception from __subclasses__" def raise_exc(): raise Exception(exc_msg) class S(metaclass=abc_ABCMeta): __subclasses__ = raise_exc with self.assertRaisesRegex(Exception, exc_msg): issubclass(int, S) def test_all_new_methods_are_called(self): class A(metaclass=abc_ABCMeta): pass class B(object): counter = 0 def __new__(cls): B.counter += 1 return super().__new__(cls) class C(A, B): pass self.assertEqual(B.counter, 0) C() self.assertEqual(B.counter, 1) def test_ABC_has___slots__(self): self.assertTrue(hasattr(abc.ABC, '__slots__')) def test_tricky_new_works(self): def with_metaclass(meta, *bases): class metaclass(type): def __new__(cls, name, this_bases, d): return meta(name, bases, d) return type.__new__(metaclass, 'temporary_class', (), {}) class A: ... class B: ... class C(with_metaclass(abc_ABCMeta, A, B)): pass self.assertEqual(C.__class__, abc_ABCMeta) class TestABCWithInitSubclass(unittest.TestCase): def test_works_with_init_subclass(self): class abc_ABC(metaclass=abc_ABCMeta): __slots__ = () saved_kwargs = {} class ReceivesClassKwargs: def __init_subclass__(cls, **kwargs): super().__init_subclass__() saved_kwargs.update(kwargs) class Receiver(ReceivesClassKwargs, abc_ABC, x=1, y=2, z=3): pass self.assertEqual(saved_kwargs, dict(x=1, y=2, z=3)) return TestLegacyAPI, TestABC, TestABCWithInitSubclass TestLegacyAPI_Py, TestABC_Py, TestABCWithInitSubclass_Py = test_factory(abc.ABCMeta, abc.get_cache_token) TestLegacyAPI_C, TestABC_C, TestABCWithInitSubclass_C = test_factory(_py_abc.ABCMeta, _py_abc.get_cache_token) if __name__ == "__main__": unittest.main()