Fix ordering issue with a user-defined Responses-activation (#4896)

moto/core/custom_responses_mock.py

@@ -100,7 +100,8 @@ def not_implemented_callback(request):
 #  - Same request, executed again, will be matched on the subsequent match, which happens to be the catch-all, not-yet-implemented, callback
 # Fix: Always return the first match
 def _find_first_match_legacy(self, request):
-    matches = [match for match in self._matches if match.matches(request)]
+    all_possibles = self._matches + responses._default_mock._matches
+    matches = [match for match in all_possibles if match.matches(request)]
 
     # Look for implemented callbacks first
     implemented_matches = [
@@ -120,7 +121,8 @@ def _find_first_match_legacy(self, request):
 def _find_first_match(self, request):
     matches = []
     match_failed_reasons = []
-    for match in self._matches:
+    all_possibles = self._matches + responses._default_mock._matches
+    for match in all_possibles:
         match_result, reason = match.matches(request)
         if match_result:
             matches.append(match)

moto/core/responses_custom_registry.py

@@ -1,9 +1,9 @@
 # This will only exist in responses >= 0.17
-from responses import registries
+import responses
 from .custom_responses_mock import CallbackResponse, not_implemented_callback
 
 
-class CustomRegistry(registries.FirstMatchRegistry):
+class CustomRegistry(responses.registries.FirstMatchRegistry):
     """
     Custom Registry that returns requests in an order that makes sense for Moto:
      - Implemented callbacks take precedence over non-implemented-callbacks
@@ -11,9 +11,10 @@ class CustomRegistry(registries.FirstMatchRegistry):
     """
 
     def find(self, request):
+        all_possibles = responses._default_mock._registry.registered + self.registered
         found = []
         match_failed_reasons = []
-        for response in self.registered:
+        for response in all_possibles:
             match_result, reason = response.matches(request)
             if match_result:
                 found.append(response)

tests/test_core/test_responses_module.py

@@ -0,0 +1,63 @@
+"""
+Ensure that the responses module plays nice with our mocks
+"""
+
+import boto3
+import requests
+import responses
+from moto import mock_s3, settings
+from unittest import SkipTest, TestCase
+
+
+class TestResponsesModule(TestCase):
+    def setUp(self):
+        if settings.TEST_SERVER_MODE:
+            raise SkipTest("No point in testing responses-decorator in ServerMode")
+
+    @mock_s3
+    @responses.activate
+    def test_moto_first(self):
+
+        """
+        Verify we can activate a user-defined `responses` on top of our Moto mocks
+        """
+        self.moto_responses_compatibility()
+
+    @responses.activate
+    @mock_s3
+    def test_moto_second(self):
+        """
+        Verify we can load Moto after activating a `responses`-mock
+        """
+        self.moto_responses_compatibility()
+
+    def moto_responses_compatibility(self):
+        responses.add(
+            responses.GET, url="http://127.0.0.1/lkdsfjlkdsa", json={"a": "4"},
+        )
+        s3 = boto3.client("s3")
+        s3.create_bucket(Bucket="mybucket")
+        s3.put_object(Bucket="mybucket", Key="name", Body="value")
+        s3.get_object(Bucket="mybucket", Key="name")["Body"].read()
+        with requests.get("http://127.0.0.1/lkdsfjlkdsa",) as r:
+            assert r.json() == {"a": "4"}
+
+    @responses.activate
+    def test_moto_as_late_as_possible(self):
+        """
+        Verify we can load moto after registering a response
+        """
+        responses.add(
+            responses.GET, url="http://127.0.0.1/lkdsfjlkdsa", json={"a": "4"},
+        )
+        with mock_s3():
+            s3 = boto3.client("s3")
+            s3.create_bucket(Bucket="mybucket")
+            s3.put_object(Bucket="mybucket", Key="name", Body="value")
+            # This mock exists within Moto
+            with requests.get("http://127.0.0.1/lkdsfjlkdsa",) as r:
+                assert r.json() == {"a": "4"}
+
+        # And outside of Moto
+        with requests.get("http://127.0.0.1/lkdsfjlkdsa",) as r:
+            assert r.json() == {"a": "4"}