cpython/Lib/test/test_abc.py

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# Copyright 2007 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.
"""Unit tests for abc.py."""
import sys
import unittest
from test import test_support
import abc
__metaclass__ = type
class TestABC(unittest.TestCase):
def test_abstractmethod_basics(self):
@abc.abstractmethod
def foo(self): pass
self.assertEqual(foo.__isabstractmethod__, True)
def bar(self): pass
self.assertEqual(hasattr(bar, "__isabstractmethod__"), False)
def test_abstractproperty_basics(self):
@abc.abstractproperty
def foo(self): pass
self.assertEqual(foo.__isabstractmethod__, True)
def bar(self): pass
self.assertEqual(hasattr(bar, "__isabstractmethod__"), False)
class C:
__metaclass__ = abc.ABCMeta
@abc.abstractproperty
def foo(self): return 3
class D(C):
@property
def foo(self): return super(D, self).foo
self.assertEqual(D().foo, 3)
def test_abstractmethod_integration(self):
for abstractthing in [abc.abstractmethod, abc.abstractproperty]:
class C:
__metaclass__ = abc.ABCMeta
@abstractthing
def foo(self): pass # abstract
def bar(self): pass # concrete
self.assertEqual(C.__abstractmethods__, set(["foo"]))
self.assertRaises(TypeError, C) # because foo is abstract
class D(C):
def bar(self): pass # concrete override of concrete
self.assertEqual(D.__abstractmethods__, set(["foo"]))
self.assertRaises(TypeError, D) # because foo is still abstract
class E(D):
def foo(self): pass
self.assertEqual(E.__abstractmethods__, set())
E() # now foo is concrete, too
class F(E):
@abstractthing
def bar(self): pass # abstract override of concrete
self.assertEqual(F.__abstractmethods__, set(["bar"]))
self.assertRaises(TypeError, F) # because bar is abstract now
def test_registration_basics(self):
class A:
__metaclass__ = abc.ABCMeta
class B:
pass
b = B()
self.assertEqual(issubclass(B, A), False)
self.assertEqual(isinstance(b, A), False)
A.register(B)
self.assertEqual(issubclass(B, A), True)
self.assertEqual(isinstance(b, A), True)
class C(B):
pass
c = C()
self.assertEqual(issubclass(C, A), True)
self.assertEqual(isinstance(c, A), True)
def test_registration_builtins(self):
class A:
__metaclass__ = abc.ABCMeta
A.register(int)
self.assertEqual(isinstance(42, A), True)
self.assertEqual(issubclass(int, A), True)
class B(A):
pass
B.register(basestring)
self.assertEqual(isinstance("", A), True)
self.assertEqual(issubclass(str, A), True)
def test_registration_edge_cases(self):
class A:
__metaclass__ = abc.ABCMeta
A.register(A) # should pass silently
class A1(A):
pass
self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
class B:
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_registration_transitiveness(self):
class A:
__metaclass__ = abc.ABCMeta
self.failUnless(issubclass(A, A))
class B:
__metaclass__ = abc.ABCMeta
self.failIf(issubclass(A, B))
self.failIf(issubclass(B, A))
class C:
__metaclass__ = abc.ABCMeta
A.register(B)
class B1(B):
pass
self.failUnless(issubclass(B1, A))
class C1(C):
pass
B1.register(C1)
self.failIf(issubclass(C, B))
self.failIf(issubclass(C, B1))
self.failUnless(issubclass(C1, A))
self.failUnless(issubclass(C1, B))
self.failUnless(issubclass(C1, B1))
C1.register(int)
class MyInt(int):
pass
self.failUnless(issubclass(MyInt, A))
self.failUnless(isinstance(42, A))
def test_all_new_methods_are_called(self):
class A:
__metaclass__ = abc.ABCMeta
class B:
counter = 0
def __new__(cls):
B.counter += 1
return super(B, cls).__new__(cls)
class C(A, B):
pass
self.assertEqual(B.counter, 0)
C()
self.assertEqual(B.counter, 1)
def test_main():
test_support.run_unittest(TestABC)
if __name__ == "__main__":
unittest.main()