| """Unit tests for __instancecheck__ and __subclasscheck__.""" |
| |
| import unittest |
| |
| |
| class ABC(type): |
| |
| def __instancecheck__(cls, inst): |
| """Implement isinstance(inst, cls).""" |
| return any(cls.__subclasscheck__(c) |
| for c in {type(inst), inst.__class__}) |
| |
| def __subclasscheck__(cls, sub): |
| """Implement issubclass(sub, cls).""" |
| candidates = cls.__dict__.get("__subclass__", set()) | {cls} |
| return any(c in candidates for c in sub.mro()) |
| |
| |
| class Integer(metaclass=ABC): |
| __subclass__ = {int} |
| |
| |
| class SubInt(Integer): |
| pass |
| |
| |
| class TypeChecksTest(unittest.TestCase): |
| |
| def testIsSubclassInternal(self): |
| self.assertEqual(Integer.__subclasscheck__(int), True) |
| self.assertEqual(Integer.__subclasscheck__(float), False) |
| |
| def testIsSubclassBuiltin(self): |
| self.assertEqual(issubclass(int, Integer), True) |
| self.assertEqual(issubclass(int, (Integer,)), True) |
| self.assertEqual(issubclass(float, Integer), False) |
| self.assertEqual(issubclass(float, (Integer,)), False) |
| |
| def testIsInstanceBuiltin(self): |
| self.assertEqual(isinstance(42, Integer), True) |
| self.assertEqual(isinstance(42, (Integer,)), True) |
| self.assertEqual(isinstance(3.14, Integer), False) |
| self.assertEqual(isinstance(3.14, (Integer,)), False) |
| |
| def testIsInstanceActual(self): |
| self.assertEqual(isinstance(Integer(), Integer), True) |
| self.assertEqual(isinstance(Integer(), (Integer,)), True) |
| |
| def testIsSubclassActual(self): |
| self.assertEqual(issubclass(Integer, Integer), True) |
| self.assertEqual(issubclass(Integer, (Integer,)), True) |
| |
| def testSubclassBehavior(self): |
| self.assertEqual(issubclass(SubInt, Integer), True) |
| self.assertEqual(issubclass(SubInt, (Integer,)), True) |
| self.assertEqual(issubclass(SubInt, SubInt), True) |
| self.assertEqual(issubclass(SubInt, (SubInt,)), True) |
| self.assertEqual(issubclass(Integer, SubInt), False) |
| self.assertEqual(issubclass(Integer, (SubInt,)), False) |
| self.assertEqual(issubclass(int, SubInt), False) |
| self.assertEqual(issubclass(int, (SubInt,)), False) |
| self.assertEqual(isinstance(SubInt(), Integer), True) |
| self.assertEqual(isinstance(SubInt(), (Integer,)), True) |
| self.assertEqual(isinstance(SubInt(), SubInt), True) |
| self.assertEqual(isinstance(SubInt(), (SubInt,)), True) |
| self.assertEqual(isinstance(42, SubInt), False) |
| self.assertEqual(isinstance(42, (SubInt,)), False) |
| |
| |
| if __name__ == "__main__": |
| unittest.main() |