Use workflow.now() for op future resolution time

Author: dandavison

tests/nexus/test_workflow_caller_cancellation_types.py

@@ -189,9 +189,7 @@ async def run(self, input: Input) -> CancellationResult:
         try:
             await op_handle
         except exceptions.NexusOperationError:
-            test_context.caller_op_future_resolved.set_result(
-                datetime.now(timezone.utc)
-            )
+            test_context.caller_op_future_resolved.set_result(workflow.now())
             assert op_handle.operation_token
             if input.cancellation_type in [
                 workflow.NexusOperationCancellationType.TRY_CANCEL,

tests/nexus/test_workflow_caller_cancellation_types_when_cancel_handler_fails.py

@@ -185,7 +185,7 @@ async def run(self, input: Input) -> CancellationResult:
             error_type = err.__class__.__name__
             error_cause_type = err.__cause__.__class__.__name__
 
-        test_context.caller_op_future_resolved.set_result(datetime.now(timezone.utc))
+        test_context.caller_op_future_resolved.set_result(workflow.now())
         assert op_handle.operation_token
         await workflow.wait_condition(lambda: self.released)
         return CancellationResult(