fix override logic

Author: mabdinur

tests/utils.py

@@ -990,13 +990,13 @@ def __init__(
         tracer=None,
         _config=None,
     ):
-        # type: (...) -> None
         super(TestPin, self).__init__(service=service, tags=tags, _config=_config)
         if tracer is not None:
             self.tracer = tracer
 
     def __setattr__(self, name, value):
         if name == "tracer":
+            # TestPin supports overriding the global tracer but ddtrace.trace.Pin does not.
             super(Pin, self).__setattr__(name, value)
         else:
             super(TestPin, self).__setattr__(name, value)
@@ -1018,7 +1018,10 @@ def override(
         elif isinstance(pin, TestPin):
             pin.clone(service=service, tags=tags, tracer=tracer).onto(obj)
         else:
-            pin.clone(service=service, tags=tags).onto(obj)
+            # replace ddtrace.trace.Pin with tests.utils.TestPin. This will
+            # allow us to override the global tracer in tests.
+            pin.remove_from(obj)
+            TestPin(service=service, tags=tags, tracer=tracer).onto(obj)
 
     def clone(
         self,