def test_top(self):
key = "foo"
context = ContextStack({key: "bar"}, {key: "buzz"})
self.assertEqual(context.get(key), "buzz")
top = context.top()
self.assertEqual(top, {"foo": "buzz"})
# Make sure calling top() didn't remove the item from the stack.
self.assertEqual(context.get(key), "buzz")
