Add assert_on_exception parameter to RequestsMock

When set to True, assertions about unfired requests will be raised even
when an exception occurs in the context manager. This provides valuable
debugging context about which mocked requests were or weren't called
when debugging test failures.

By default (assert_on_exception=False), the assertion is suppressed to
avoid masking the original exception.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: RJPercival

README.rst

@@ -917,6 +917,34 @@ the ``assert_all_requests_are_fired`` value:
                 content_type="application/json",
             )
 
+By default, when an exception occurs within the context manager, the assertion
+about unfired requests is suppressed to avoid masking the original exception.
+However, this can hide valuable context about which mocked requests were or weren't
+called. You can use ``assert_on_exception=True`` to always see this information when
+debugging test failures.
+
+.. code-block:: python
+
+    import responses
+    import requests
+
+
+    def test_with_assert_on_exception():
+        with responses.RequestsMock(
+            assert_all_requests_are_fired=True, assert_on_exception=True
+        ) as rsps:
+            rsps.add(responses.GET, "http://example.com/users", body="test")
+            rsps.add(responses.GET, "http://example.com/profile", body="test")
+            requests.get("http://example.com/users")
+            raise ValueError("Something went wrong")
+
+        # Output:
+        # ValueError: Something went wrong
+        #
+        # During handling of the above exception, another exception occurred:
+        #
+        # AssertionError: Not all requests have been executed [('GET', 'http://example.com/profile')]
+
 Assert Request Call Count
 -------------------------
 

responses/__init__.py

@@ -730,11 +730,13 @@ def __init__(
         registry: Type[FirstMatchRegistry] = FirstMatchRegistry,
         *,
         real_adapter_send: "_HTTPAdapterSend" = _real_send,
+        assert_on_exception: bool = False,
     ) -> None:
         self._calls: CallList = CallList()
         self.reset()
         self._registry: FirstMatchRegistry = registry()  # call only after reset
         self.assert_all_requests_are_fired: bool = assert_all_requests_are_fired
+        self.assert_on_exception: bool = assert_on_exception
         self.response_callback: Optional[Callable[[Any], Response]] = response_callback
         self.passthru_prefixes: Tuple[_URLPatternType, ...] = tuple(passthru_prefixes)
         self.target: str = target
@@ -993,7 +995,7 @@ def __enter__(self) -> "RequestsMock":
     def __exit__(self, type: Any, value: Any, traceback: Any) -> None:
         success = type is None
         try:
-            self.stop(allow_assert=success)
+            self.stop(allow_assert=success or self.assert_on_exception)
         finally:
             self.reset()
 

responses/tests/test_responses.py

@@ -1217,6 +1217,57 @@ def test_some_second_function():
     assert_reset()
 
 
+def test_assert_on_exception():
+    """Test that assert_on_exception controls assertion behavior during exceptions."""
+
+    def run():
+        # Default behavior (assert_on_exception=False):
+        # assertion should NOT be raised when an exception occurs
+        with pytest.raises(ValueError) as value_exc_info:
+            with responses.RequestsMock(
+                assert_all_requests_are_fired=True, assert_on_exception=False
+            ) as m:
+                m.add(responses.GET, "http://example.com", body=b"test")
+                m.add(responses.GET, "http://not-called.com", body=b"test")
+                requests.get("http://example.com")
+                raise ValueError("Main error")
+
+        # Should only see the ValueError, not the AssertionError about unfired requests
+        assert "Main error" in str(value_exc_info.value)
+        assert "not-called.com" not in str(value_exc_info.value)
+
+        # With assert_on_exception=True: assertion WILL be raised even with an exception
+        # The AssertionError will be the primary exception, with the ValueError as context
+        with pytest.raises(AssertionError) as assert_exc_info:
+            with responses.RequestsMock(
+                assert_all_requests_are_fired=True, assert_on_exception=True
+            ) as m:
+                m.add(responses.GET, "http://example.com", body=b"test")
+                m.add(responses.GET, "http://not-called.com", body=b"test")
+                requests.get("http://example.com")
+                raise ValueError("Main error")
+
+        # The AssertionError should mention the unfired request
+        assert "not-called.com" in str(assert_exc_info.value)
+        # Python automatically chains exceptions, so we should see both in the traceback
+        assert isinstance(assert_exc_info.value.__context__, ValueError)
+        assert "Main error" in str(assert_exc_info.value.__context__)
+
+        # Test that both work normally when no other exception occurs
+        with pytest.raises(AssertionError) as assert_exc_info2:
+            with responses.RequestsMock(
+                assert_all_requests_are_fired=True, assert_on_exception=True
+            ) as m:
+                m.add(responses.GET, "http://example.com", body=b"test")
+                m.add(responses.GET, "http://not-called.com", body=b"test")
+                requests.get("http://example.com")
+
+        assert "not-called.com" in str(assert_exc_info2.value)
+
+    run()
+    assert_reset()
+
+
 def test_allow_redirects_samehost():
     redirecting_url = "http://example.com"
     final_url_path = "/1"