diff --git a/tests/conftest.py b/tests/conftest.py
index e9b0b5b4756..a47e750a43b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -245,6 +245,45 @@ def pytest_runtest_setup() -> None:
             MySQLdb_converters.DateTime2literal
         )
 
+    import httpx  # pylint: disable=import-outside-toplevel
+    from respx.models import (  # pylint: disable=import-outside-toplevel
+        Route,
+        SideEffectError,
+    )
+    from respx.types import RouteResultTypes  # pylint: disable=import-outside-toplevel
+
+    def _resolve_side_effect(
+        self, request: httpx.Request, **kwargs: Any
+    ) -> RouteResultTypes:
+        effect = self._next_side_effect()
+
+        # Handle Exception `instance` side effect
+        if isinstance(effect, Exception):
+            import copy  # pylint: disable=import-outside-toplevel
+
+            raise SideEffectError(self, origin=copy(effect))
+
+        # Handle Exception `type` side effect
+        if isinstance(effect, type):
+            assert issubclass(effect, Exception)
+            raise SideEffectError(
+                self,
+                origin=(
+                    effect("Mock Error", request=request)
+                    if issubclass(effect, httpx.RequestError)
+                    else effect()
+                ),
+            )
+
+        # Handle `Callable` side effect
+        if callable(effect):
+            return self._call_side_effect(effect, request, **kwargs)
+
+        # Resolved effect is a mocked response
+        return effect
+
+    Route._resolve_side_effect = _resolve_side_effect
+
 
 def ha_datetime_to_fakedatetime(datetime) -> freezegun.api.FakeDatetime:  # type: ignore[name-defined]
     """Convert datetime to FakeDatetime.