Add examples to section on mock

diff --git a/docs/writing/tests.rst b/docs/writing/tests.rst
index 342b133..975adf6 100644 (file)
--- a/docs/writing/tests.rst
+++ b/docs/writing/tests.rst
@@ -260,5 +260,37 @@ mock is a library for testing in Python.
 It allows you to replace parts of your system under test with mock objects and
 make assertions about how they have been used.
 
 It allows you to replace parts of your system under test with mock objects and
 make assertions about how they have been used.
 

+For example, you can monkey patch a method
+
+::
+
+    from mock import MagicMock
+    thing = ProductionClass()
+    thing.method = MagicMock(return_value=3)
+    thing.method(3, 4, 5, key='value')
+
+    thing.method.assert_called_with(3, 4, 5, key='value')
+
+To mock classes or objects in a module under test, use the ``patch`` decorator.
+In the example below, an external search system is replaced with a mock that
+always returns the same result (but only for the duration of the test).
+
+::
+
+    def mock_search(self):
+        class MockSearchQuerySet(SearchQuerySet):
+            def __iter__(self):
+                return iter(["foo", "bar", "baz"])
+        return MockSearchQuerySet()
+
+    # SearchForm here refers to the imported class reference in myapp,
+    # not where the SearchForm class itself is imported from
+    @mock.patch('myapp.SearchForm.search', mock_search)
+    def test_new_watchlist_activities(self):
+        # get_search_results runs a search and iterates over the result 
+        self.assertEqual(len(myapp.get_search_results(q="fish")), 3)
+
+Mock has many other ways you can configure it and control its behaviour.
+

     `mock <http://www.voidspace.org.uk/python/mock/>`_
 
     `mock <http://www.voidspace.org.uk/python/mock/>`_