Fix nested decorators causing mocks leaking (#500)

* clean patcher on exit
* add tests and comments

Closes #481

CHANGES

@@ -3,6 +3,8 @@
 
 * Added a registry that provides more strict ordering based on the invocation index.
   See `responses.registries.OrderedRegistry`.
+* Prevent `responses.activate` decorator to leak, if wrapped function called from within another
+  wrapped function. Also, allow calling of above mentioned chain. See #481 for more details.
 * Expose `get_registry()` method of `RequestsMock` object. Replaces internal `_get_registry()`.
 * `query_param_matcher` can now accept dictionaries with `int` and `float` values.
 * Add support for the `loose` version of `query_param_matcher` via named argument `strict_match`.

responses/__init__.py

@@ -561,6 +561,7 @@ def reset(self):
         self._registry = FirstMatchRegistry()
         self._calls.reset()
         self.passthru_prefixes = ()
+        self._patcher = None
 
     def add(
         self,
@@ -806,14 +807,21 @@ def _on_request(self, adapter, request, **kwargs):
         return response
 
     def start(self):
+        if self._patcher:
+            # we must not override value of the _patcher if already applied
+            return
+
         def unbound_on_send(adapter, request, *a, **kwargs):
             return self._on_request(adapter, request, *a, **kwargs)
 
         self._patcher = std_mock.patch(target=self.target, new=unbound_on_send)
         self._patcher.start()
 
     def stop(self, allow_assert=True):
-        self._patcher.stop()
+        if self._patcher:
+            # prevent stopping unstarted patchers
+            self._patcher.stop()
+
         if not self.assert_all_requests_are_fired:
             return
 

responses/test_responses.py

@@ -1983,3 +1983,38 @@ async def run():
 
     await run()
     assert_reset()
+
+
+class TestMultipleWrappers:
+    """Test to validate that multiple decorators could be applied.
+
+    Ensures that we can call one function that is wrapped with
+    ``responses.activate`` decorator from within another wrapped function.
+
+    Validates that mock patch is not leaked to other tests.
+    For more detail refer to https://github.com/getsentry/responses/issues/481
+    """
+
+    @responses.activate
+    def test_wrapped(self):
+        responses.add(responses.GET, "http://example.com/1", body="Hello 1")
+        assert b"Hello 1" == requests.get("http://example.com/1").content
+
+    @responses.activate
+    def test_call_another_wrapped_function(self):
+        self.test_wrapped()
+
+    def test_mock_not_leaked(self, httpserver):
+        """
+        Validate that ``responses.activate`` does not leak to unpatched test.
+
+        Parameters
+        ----------
+        httpserver : ContentServer
+            Mock real HTTP server
+
+        """
+        httpserver.serve_content("OK", code=969, headers={"Content-Type": "text/plain"})
+
+        response = requests.get(httpserver.url)
+        assert response.status_code == 969