Merge pull request #12 from fogo/add-spy-stub

Added methods spy and stub to mocker fixture

Author: nicoddemus

README.rst

@@ -69,6 +69,46 @@ fixture:
         ret = [mocker.Mock(return_value=True), mocker.Mock(return_value=True)]
         mocker.patch('mylib.func', side_effect=ret)
 
+*New in version 0.5*
+
+Spy
+---
+
+*New in version 0.6*
+
+The spy acts exactly like the original method in all cases, except it allows use of `mock`
+features with it, like retrieving call count.
+
+.. code-block:: python
+
+    def test_spy(mocker):
+        class Foo(object):
+            def bar(self):
+                return 42
+
+        foo = Foo()
+        mocker.spy(foo, 'bar')
+        assert foo.bar() == 42
+        assert foo.bar.call_count == 1
+
+Stub
+----
+
+*New in version 0.6*
+
+The stub is a mock object that accepts any arguments and is useful to test callbacks, for instance.
+
+.. code-block:: python
+
+    def test_stub(mocker):
+        def foo(on_something):
+            on_something('foo', 'bar')
+
+        stub = mocker.stub()
+
+        foo(stub)
+        stub.assert_called_once_with('foo', 'bar')
+
 Note
 ----
 

pytest_mock.py

@@ -31,6 +31,31 @@ def stopall(self):
             p.stop()
         self._patches[:] = []
 
+    def spy(self, obj, method_name):
+        """
+        Creates a spy of method. It will run method normally, but it is now possible to use `mock`
+        call features with it, like call count.
+
+        :param object obj:
+            An object.
+
+        :param unicode method_name:
+            A method in object.
+
+        :return: mock.MagicMock
+            Spy object.
+        """
+        return self.patch.object(obj, method_name, side_effect=getattr(obj, method_name))
+
+    def stub(self):
+        """
+        Creates a stub method. It accepts any arguments. Ideal to register to callbacks in tests.
+
+        :return: mock.MagicMock
+            Stub object.
+        """
+        return mock_module.MagicMock(spec=lambda *args, **kwargs: None)
+
     class _Patcher(object):
         """
         Object to provide the same interface as mock.patch, mock.patch.object,

test_pytest_mock.py

@@ -136,3 +136,26 @@ def test_mocker_has_mock_class_as_attribute_for_instantiation():
 
     mocker = MockFixture()
     assert isinstance(mocker.Mock(), mock_module.Mock)
+
+
+def test_mocker_spy(mocker):
+    class Foo(object):
+
+        def bar(self, arg):
+            return arg * 2
+
+    foo = Foo()
+    spy = mocker.spy(foo, 'bar')
+
+    assert foo.bar(arg=10) == 20
+    spy.assert_called_once_with(arg=10)
+
+
+def test_mocker_stub(mocker):
+    def foo(on_something):
+        on_something('foo', 'bar')
+
+    stub = mocker.stub()
+
+    foo(stub)
+    stub.assert_called_once_with('foo', 'bar')