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Frank Wierzbicki committed b045281 Draft
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  • Parent commits ca45c91

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File Lib/test/test_funcattrs.py

+from test import test_support
+import types
+import unittest
+
+class FuncAttrsTest(unittest.TestCase):
+    def setUp(self):
+        class F:
+            def a(self):
+                pass
+        def b():
+            return 3
+        self.f = F
+        self.fi = F()
+        self.b = b
+
+    def cannot_set_attr(self, obj, name, value, exceptions):
+        # Helper method for other tests.
+        try:
+            setattr(obj, name, value)
+        except exceptions:
+            pass
+        else:
+            self.fail("shouldn't be able to set %s to %r" % (name, value))
+        try:
+            delattr(obj, name)
+        except exceptions:
+            pass
+        else:
+            self.fail("shouldn't be able to del %s" % name)
+
+
+class FunctionPropertiesTest(FuncAttrsTest):
+    # Include the external setUp method that is common to all tests
+    def test_module(self):
+        self.assertEqual(self.b.__module__, __name__)
+
+    def test_dir_includes_correct_attrs(self):
+        self.b.known_attr = 7
+        self.assertIn('known_attr', dir(self.b),
+                        "set attributes not in dir listing of method")
+        # Test on underlying function object of method
+        self.f.a.im_func.known_attr = 7
+        self.assertIn('known_attr', dir(self.f.a),
+                        "set attribute on unbound method implementation in "
+                        "class not in dir")
+        self.assertIn('known_attr', dir(self.fi.a),
+                        "set attribute on unbound method implementations, "
+                        "should show up in next dir")
+
+    def test_duplicate_function_equality(self):
+        # Body of `duplicate' is the exact same as self.b
+        def duplicate():
+            'my docstring'
+            return 3
+        self.assertNotEqual(self.b, duplicate)
+
+    def test_copying_func_code(self):
+        def test(): pass
+        self.assertEqual(test(), None)
+        test.func_code = self.b.func_code
+        self.assertEqual(test(), 3) # self.b always returns 3, arbitrarily
+
+    def test_func_globals(self):
+        self.assertIs(self.b.func_globals, globals())
+        self.cannot_set_attr(self.b, 'func_globals', 2, TypeError)
+
+    def test_func_closure(self):
+        a = 12
+        def f(): print a
+        c = f.func_closure
+        self.assertIsInstance(c, tuple)
+        self.assertEqual(len(c), 1)
+        # don't have a type object handy
+        self.assertEqual(c[0].__class__.__name__, "cell")
+        self.cannot_set_attr(f, "func_closure", c, TypeError)
+
+    def test_empty_cell(self):
+        def f(): print a
+        try:
+            f.func_closure[0].cell_contents
+        except ValueError:
+            pass
+        else:
+            self.fail("shouldn't be able to read an empty cell")
+        a = 12
+
+    def test_func_name(self):
+        self.assertEqual(self.b.__name__, 'b')
+        self.assertEqual(self.b.func_name, 'b')
+        self.b.__name__ = 'c'
+        self.assertEqual(self.b.__name__, 'c')
+        self.assertEqual(self.b.func_name, 'c')
+        self.b.func_name = 'd'
+        self.assertEqual(self.b.__name__, 'd')
+        self.assertEqual(self.b.func_name, 'd')
+        # __name__ and func_name must be a string
+        self.cannot_set_attr(self.b, '__name__', 7, TypeError)
+        self.cannot_set_attr(self.b, 'func_name', 7, TypeError)
+        # __name__ must be available when in restricted mode. Exec will raise
+        # AttributeError if __name__ is not available on f.
+        s = """def f(): pass\nf.__name__"""
+        exec s in {'__builtins__': {}}
+        # Test on methods, too
+        self.assertEqual(self.f.a.__name__, 'a')
+        self.assertEqual(self.fi.a.__name__, 'a')
+        self.cannot_set_attr(self.f.a, "__name__", 'a', AttributeError)
+        self.cannot_set_attr(self.fi.a, "__name__", 'a', AttributeError)
+
+    def test_func_code(self):
+        num_one, num_two = 7, 8
+        def a(): pass
+        def b(): return 12
+        def c(): return num_one
+        def d(): return num_two
+        def e(): return num_one, num_two
+        for func in [a, b, c, d, e]:
+            self.assertEqual(type(func.func_code), types.CodeType)
+        self.assertEqual(c(), 7)
+        self.assertEqual(d(), 8)
+        d.func_code = c.func_code
+        self.assertEqual(c.func_code, d.func_code)
+        self.assertEqual(c(), 7)
+        # self.assertEqual(d(), 7)
+        try:
+            b.func_code = c.func_code
+        except ValueError:
+            pass
+        else:
+            self.fail("func_code with different numbers of free vars should "
+                      "not be possible")
+        try:
+            e.func_code = d.func_code
+        except ValueError:
+            pass
+        else:
+            self.fail("func_code with different numbers of free vars should "
+                      "not be possible")
+
+    def test_blank_func_defaults(self):
+        self.assertEqual(self.b.func_defaults, None)
+        del self.b.func_defaults
+        self.assertEqual(self.b.func_defaults, None)
+
+    def test_func_default_args(self):
+        def first_func(a, b):
+            return a+b
+        def second_func(a=1, b=2):
+            return a+b
+        self.assertEqual(first_func.func_defaults, None)
+        self.assertEqual(second_func.func_defaults, (1, 2))
+        first_func.func_defaults = (1, 2)
+        self.assertEqual(first_func.func_defaults, (1, 2))
+        self.assertEqual(first_func(), 3)
+        self.assertEqual(first_func(3), 5)
+        self.assertEqual(first_func(3, 5), 8)
+        del second_func.func_defaults
+        self.assertEqual(second_func.func_defaults, None)
+        try:
+            second_func()
+        except TypeError:
+            pass
+        else:
+            self.fail("func_defaults does not update; deleting it does not "
+                      "remove requirement")
+
+
+class InstancemethodAttrTest(FuncAttrsTest):
+    def test_im_class(self):
+        self.assertEqual(self.f.a.im_class, self.f)
+        self.assertEqual(self.fi.a.im_class, self.f)
+        self.cannot_set_attr(self.f.a, "im_class", self.f, TypeError)
+        self.cannot_set_attr(self.fi.a, "im_class", self.f, TypeError)
+
+    def test_im_func(self):
+        self.f.b = self.b
+        self.assertEqual(self.f.b.im_func, self.b)
+        self.assertEqual(self.fi.b.im_func, self.b)
+        self.cannot_set_attr(self.f.b, "im_func", self.b, TypeError)
+        self.cannot_set_attr(self.fi.b, "im_func", self.b, TypeError)
+
+    def test_im_self(self):
+        self.assertEqual(self.f.a.im_self, None)
+        self.assertEqual(self.fi.a.im_self, self.fi)
+        self.cannot_set_attr(self.f.a, "im_self", None, TypeError)
+        self.cannot_set_attr(self.fi.a, "im_self", self.fi, TypeError)
+
+    def test_im_func_non_method(self):
+        # Behavior should be the same when a method is added via an attr
+        # assignment
+        self.f.id = types.MethodType(id, None, self.f)
+        self.assertEqual(self.fi.id(), id(self.fi))
+        self.assertNotEqual(self.fi.id(), id(self.f))
+        # Test usage
+        try:
+            self.f.id.unknown_attr
+        except AttributeError:
+            pass
+        else:
+            self.fail("using unknown attributes should raise AttributeError")
+        # Test assignment and deletion
+        self.cannot_set_attr(self.f.id, 'unknown_attr', 2, AttributeError)
+        self.cannot_set_attr(self.fi.id, 'unknown_attr', 2, AttributeError)
+
+    def test_implicit_method_properties(self):
+        self.f.a.im_func.known_attr = 7
+        self.assertEqual(self.f.a.known_attr, 7)
+        self.assertEqual(self.fi.a.known_attr, 7)
+
+
+class ArbitraryFunctionAttrTest(FuncAttrsTest):
+    def test_set_attr(self):
+        # setting attributes only works on function objects
+        self.b.known_attr = 7
+        self.assertEqual(self.b.known_attr, 7)
+        for func in [self.f.a, self.fi.a]:
+            try:
+                func.known_attr = 7
+            except AttributeError:
+                pass
+            else:
+                self.fail("setting attributes on methods should raise error")
+
+    def test_delete_unknown_attr(self):
+        try:
+            del self.b.unknown_attr
+        except AttributeError:
+            pass
+        else:
+            self.fail("deleting unknown attribute should raise TypeError")
+
+    def test_setting_attrs_duplicates(self):
+        try:
+            self.f.a.klass = self.f
+        except AttributeError:
+            pass
+        else:
+            self.fail("setting arbitrary attribute in unbound function "
+                      " should raise AttributeError")
+        self.f.a.im_func.klass = self.f
+        for method in [self.f.a, self.fi.a, self.fi.a.im_func]:
+            self.assertEqual(method.klass, self.f)
+
+    def test_unset_attr(self):
+        for func in [self.b, self.f.a, self.fi.a]:
+            try:
+                func.non_existent_attr
+            except AttributeError:
+                pass
+            else:
+                self.fail("using unknown attributes should raise "
+                          "AttributeError")
+
+
+class FunctionDictsTest(FuncAttrsTest):
+    def test_setting_dict_to_invalid(self):
+        self.cannot_set_attr(self.b, '__dict__', None, TypeError)
+        self.cannot_set_attr(self.b, 'func_dict', None, TypeError)
+        from UserDict import UserDict
+        d = UserDict({'known_attr': 7})
+        self.cannot_set_attr(self.f.a.im_func, '__dict__', d, TypeError)
+        self.cannot_set_attr(self.fi.a.im_func, '__dict__', d, TypeError)
+
+    def test_setting_dict_to_valid(self):
+        d = {'known_attr': 7}
+        self.b.__dict__ = d
+        # Setting dict is only possible on the underlying function objects
+        self.f.a.im_func.__dict__ = d
+        # Test assignment
+        self.assertIs(d, self.b.__dict__)
+        self.assertIs(d, self.b.func_dict)
+        # ... and on all the different ways of referencing the method's func
+        self.assertIs(d, self.f.a.im_func.__dict__)
+        self.assertIs(d, self.f.a.__dict__)
+        self.assertIs(d, self.fi.a.im_func.__dict__)
+        self.assertIs(d, self.fi.a.__dict__)
+        # Test value
+        self.assertEqual(self.b.known_attr, 7)
+        self.assertEqual(self.b.__dict__['known_attr'], 7)
+        self.assertEqual(self.b.func_dict['known_attr'], 7)
+        # ... and again, on all the different method's names
+        self.assertEqual(self.f.a.im_func.known_attr, 7)
+        self.assertEqual(self.f.a.known_attr, 7)
+        self.assertEqual(self.fi.a.im_func.known_attr, 7)
+        self.assertEqual(self.fi.a.known_attr, 7)
+
+    def test_delete_func_dict(self):
+        try:
+            del self.b.__dict__
+        except TypeError:
+            pass
+        else:
+            self.fail("deleting function dictionary should raise TypeError")
+        try:
+            del self.b.func_dict
+        except TypeError:
+            pass
+        else:
+            self.fail("deleting function dictionary should raise TypeError")
+
+    def test_unassigned_dict(self):
+        self.assertEqual(self.b.__dict__, {})
+
+    def test_func_as_dict_key(self):
+        value = "Some string"
+        d = {}
+        d[self.b] = value
+        self.assertEqual(d[self.b], value)
+
+
+class FunctionDocstringTest(FuncAttrsTest):
+    def test_set_docstring_attr(self):
+        self.assertEqual(self.b.__doc__, None)
+        self.assertEqual(self.b.func_doc, None)
+        docstr = "A test method that does nothing"
+        self.b.__doc__ = self.f.a.im_func.__doc__ = docstr
+        self.assertEqual(self.b.__doc__, docstr)
+        self.assertEqual(self.b.func_doc, docstr)
+        self.assertEqual(self.f.a.__doc__, docstr)
+        self.assertEqual(self.fi.a.__doc__, docstr)
+        self.cannot_set_attr(self.f.a, "__doc__", docstr, AttributeError)
+        self.cannot_set_attr(self.fi.a, "__doc__", docstr, AttributeError)
+
+    def test_delete_docstring(self):
+        self.b.__doc__ = "The docstring"
+        del self.b.__doc__
+        self.assertEqual(self.b.__doc__, None)
+        self.assertEqual(self.b.func_doc, None)
+        self.b.func_doc = "The docstring"
+        del self.b.func_doc
+        self.assertEqual(self.b.__doc__, None)
+        self.assertEqual(self.b.func_doc, None)
+
+
+class StaticMethodAttrsTest(unittest.TestCase):
+    def test_func_attribute(self):
+        def f():
+            pass
+
+        c = classmethod(f)
+        self.assertTrue(c.__func__ is f)
+
+        s = staticmethod(f)
+        self.assertTrue(s.__func__ is f)
+
+
+def test_main():
+    test_support.run_unittest(FunctionPropertiesTest, InstancemethodAttrTest,
+                              ArbitraryFunctionAttrTest, FunctionDictsTest,
+                              FunctionDocstringTest,
+                              StaticMethodAttrsTest)
+
+if __name__ == "__main__":
+    test_main()