Add fixture for mock.patch.multiple

Add another fixture to support mock.patch.multiple() so that test suites
using that function don't have to import mock directly.

Change-Id: I58368dddda347410459d8f5a713e7395253c3697

doc/source/api.rst

@@ -15,6 +15,7 @@ oslotest.mockpatch
 
 .. automodule:: oslotest.mockpatch
    :members:
+   :special-members:
 
 oslotest.moxstubout
 ===================

oslotest/mockpatch.py

@@ -36,7 +36,6 @@ class PatchObject(fixtures.Fixture):
 
 
 class Patch(fixtures.Fixture):
-
     """Deal with code around mock.patch."""
 
     def __init__(self, obj, new=mock.DEFAULT, **kwargs):
@@ -49,3 +48,33 @@ class Patch(fixtures.Fixture):
         _p = mock.patch(self.obj, self.new, **self.kwargs)
         self.mock = _p.start()
         self.addCleanup(_p.stop)
+
+
+class Multiple(fixtures.Fixture):
+    """Deal with code around mock.patch.multiple."""
+
+    # Default value to trigger a MagicMock to be created for a named
+    # attribute.
+    DEFAULT = mock.DEFAULT
+
+    def __init__(self, obj, **kwargs):
+        """Initialize the mocks
+
+        Pass name=value to replace obj.name with value.
+
+        Pass name=Multiple.DEFAULT to replace obj.name with a
+        MagicMock instance.
+
+        :param obj: Object or name containing values being mocked.
+        :type obj: str or object
+        :param kwargs: names and values of attributes of obj to be mocked.
+
+        """
+        self.obj = obj
+        self.kwargs = kwargs
+
+    def setUp(self):
+        super(Multiple, self).setUp()
+        _p = mock.patch.multiple(self.obj, **self.kwargs)
+        self.mock = _p.start()
+        self.addCleanup(_p.stop)

tests/unit/test_mockpatch.py

@@ -41,6 +41,20 @@ class TestMockPatch(base.BaseTestCase):
         self.assertIsInstance(instance.bar(), mock.MagicMock)
 
 
+class TestMockMultiple(base.BaseTestCase):
+    def test_mock_multiple_with_replacement(self):
+        self.useFixture(mockpatch.Multiple('%s.Foo' % (__name__),
+                                           bar=mocking_bar))
+        instance = Foo()
+        self.assertEqual(instance.bar(), 'mocked!')
+
+    def test_mock_patch_without_replacement(self):
+        self.useFixture(mockpatch.Multiple('%s.Foo' % (__name__),
+                                           bar=mockpatch.Multiple.DEFAULT))
+        instance = Foo()
+        self.assertIsInstance(instance.bar(), mock.MagicMock)
+
+
 class TestMockPatchObject(base.BaseTestCase):
     def test_mock_patch_object_with_replacement(self):
         self.useFixture(mockpatch.PatchObject(Foo, 'bar', mocking_bar))