Add assertIn for test use.

2 files changed, 16 insertions, 1 deletions

diff --git a/test/backunittest.py b/test/backunittest.py
index 7ec34f5c..84a7f36e 100644
--- a/test/backunittest.py
+++ b/test/backunittest.py
@@ -29,6 +29,13 @@ class TestCase(unittest.TestCase):
             if exp:
                 self.fail(msg)
 
+    if _need('assertIn'):
+        def assertIn(self, member, container, msg=None):
+            """Assert that `member` is in `container`."""
+            if member not in container:
+                msg = msg or ('%r not found in %r' % (member, container))
+                self.fail(msg)
+
     if _need('assertRaisesRegexp'):
         def assertRaisesRegexp(self, excClass, regexp, callobj, *args, **kw):
             """ Just like unittest.TestCase.assertRaises,
@@ -46,7 +53,7 @@ class TestCase(unittest.TestCase):
                     # Message provided, and it didn't match: fail!
                     raise self.failureException(
                         "Right exception, wrong message: "
-                            "'%s' doesn't match '%s'" % (excMsg, regexp)
+                            "%r doesn't match %r" % (excMsg, regexp)
                         )
             # No need to catch other exceptions: They'll fail the test all by
             # themselves!
diff --git a/test/test_testing.py b/test/test_testing.py
index 316dbc1b..c632f3b5 100644
--- a/test/test_testing.py
+++ b/test/test_testing.py
@@ -92,6 +92,14 @@ class TestingTest(TestCase):
         self.assertFalse(False)
         self.assertRaises(AssertionError, self.assertFalse, True)
 
+    def test_assert_contains(self):
+        self.assertIn("abc", "hello abc")
+        self.assertIn("abc", ["xyz", "abc", "foo"])
+        self.assertIn("abc", {'abc': 1, 'xyz': 2})
+        self.assertRaises(AssertionError, self.assertIn, "abc", "xyz")
+        self.assertRaises(AssertionError, self.assertIn, "abc", ["x", "xabc"])
+        self.assertRaises(AssertionError, self.assertIn, "abc", {'x':'abc'})
+
 
 class CoverageTestTest(CoverageTest):
     """Test the methods in `CoverageTest`."""