Add workflow caller tests that confirm both async and non-async cancel methods are invoked correctly (#1281)

Co-authored-by: Thomas Hardy <thestaffofmoses@gmail.com>

Author: VegetarianOrc

tests/nexus/test_workflow_caller.py

@@ -3,6 +3,7 @@
 import asyncio
 import concurrent.futures
 import dataclasses
+import threading
 import uuid
 from collections.abc import Awaitable, Callable
 from dataclasses import dataclass
@@ -39,7 +40,11 @@
 )
 from temporalio.common import WorkflowIDConflictPolicy
 from temporalio.converter import PayloadConverter
-from temporalio.exceptions import ApplicationError, CancelledError, NexusOperationError
+from temporalio.exceptions import (
+    ApplicationError,
+    CancelledError,
+    NexusOperationError,
+)
 from temporalio.nexus import WorkflowRunOperationContext, workflow_run_operation
 from temporalio.runtime import (
     BUFFERED_METRIC_KIND_COUNTER,
@@ -1212,9 +1217,6 @@ class ServiceClassNameOutput:
     name: str
 
 
-# TODO(nexus-prerelease): async and non-async cancel methods
-
-
 @nexusrpc.service
 class ServiceInterfaceWithoutNameOverride:
     op: nexusrpc.Operation[None, ServiceClassNameOutput]
@@ -2004,3 +2006,151 @@ async def test_workflow_caller_buffered_metrics(
         and update.value == 30
         for update in updates
     )
+
+
+@workflow.defn()
+class CancelTestCallerWorkflow:
+    def __init__(self) -> None:
+        self.released = False
+
+    @workflow.run
+    async def run(self, use_async_cancel: bool, task_queue: str) -> str:
+        nexus_client = workflow.create_nexus_client(
+            service=TestAsyncAndNonAsyncCancel.CancelTestService,
+            endpoint=make_nexus_endpoint_name(task_queue),
+        )
+
+        op = (
+            TestAsyncAndNonAsyncCancel.CancelTestService.async_cancel_op
+            if use_async_cancel
+            else TestAsyncAndNonAsyncCancel.CancelTestService.non_async_cancel_op
+        )
+
+        # Start the operation and immediately request cancellation
+        # Use WAIT_REQUESTED since we just need to verify the cancel handler was called
+        handle = await nexus_client.start_operation(
+            op,
+            None,
+            cancellation_type=workflow.NexusOperationCancellationType.WAIT_REQUESTED,
+        )
+
+        # Cancel the handle to trigger the cancel method on the handler
+        handle.cancel()
+
+        try:
+            await handle
+        except NexusOperationError:
+            # Wait for release signal before completing
+            await workflow.wait_condition(lambda: self.released)
+            return "cancelled_successfully"
+
+        return "unexpected_completion"
+
+    @workflow.signal
+    def release(self) -> None:
+        self.released = True
+
+
+@pytest.fixture(scope="class")
+def cancel_test_events(request: pytest.FixtureRequest):
+    if request.cls:
+        request.cls.called_async = asyncio.Event()
+        request.cls.called_non_async = threading.Event()
+    yield
+
+
+@pytest.mark.usefixtures("cancel_test_events")
+class TestAsyncAndNonAsyncCancel:
+    called_async: asyncio.Event  # pyright: ignore[reportUninitializedInstanceVariable]
+    called_non_async: threading.Event  # pyright: ignore[reportUninitializedInstanceVariable]
+
+    class OpWithAsyncCancel(OperationHandler[None, str]):
+        def __init__(self, evt: asyncio.Event) -> None:
+            self.evt = evt
+
+        async def start(
+            self, ctx: StartOperationContext, input: None
+        ) -> StartOperationResultAsync:
+            return StartOperationResultAsync("test-token")
+
+        async def cancel(self, ctx: CancelOperationContext, token: str) -> None:
+            self.evt.set()
+
+    class OpWithNonAsyncCancel(OperationHandler[None, str]):
+        def __init__(self, evt: threading.Event) -> None:
+            self.evt = evt
+
+        def start(
+            self, ctx: StartOperationContext, input: None
+        ) -> StartOperationResultAsync:
+            return StartOperationResultAsync("test-token")
+
+        def cancel(self, ctx: CancelOperationContext, token: str) -> None:
+            self.evt.set()
+
+    @nexusrpc.service
+    class CancelTestService:
+        async_cancel_op: nexusrpc.Operation[None, str]
+        non_async_cancel_op: nexusrpc.Operation[None, str]
+
+    @service_handler(service=CancelTestService)
+    class CancelTestServiceHandler:
+        def __init__(
+            self, async_evt: asyncio.Event, non_async_evt: threading.Event
+        ) -> None:
+            self.async_evt = async_evt
+            self.non_async_evt = non_async_evt
+
+        @operation_handler
+        def async_cancel_op(self) -> OperationHandler[None, str]:
+            return TestAsyncAndNonAsyncCancel.OpWithAsyncCancel(self.async_evt)
+
+        @operation_handler
+        def non_async_cancel_op(self) -> OperationHandler[None, str]:
+            return TestAsyncAndNonAsyncCancel.OpWithNonAsyncCancel(self.non_async_evt)
+
+    @pytest.mark.parametrize("use_async_cancel", [True, False])
+    async def test_task_executor_operation_cancel_method(
+        self, client: Client, env: WorkflowEnvironment, use_async_cancel: bool
+    ):
+        """Test that both async and non-async cancel methods work for TaskExecutor-based operations."""
+        if env.supports_time_skipping:
+            pytest.skip("Nexus tests don't work with time-skipping server")
+
+        task_queue = str(uuid.uuid4())
+        async with Worker(
+            client,
+            task_queue=task_queue,
+            workflows=[CancelTestCallerWorkflow],
+            nexus_service_handlers=[
+                TestAsyncAndNonAsyncCancel.CancelTestServiceHandler(
+                    self.called_async, self.called_non_async
+                )
+            ],
+            nexus_task_executor=concurrent.futures.ThreadPoolExecutor(),
+        ):
+            await create_nexus_endpoint(task_queue, client)
+
+            caller_wf_handle = await client.start_workflow(
+                CancelTestCallerWorkflow.run,
+                args=[use_async_cancel, task_queue],
+                id=f"caller-wf-{uuid.uuid4()}",
+                task_queue=task_queue,
+            )
+
+            # Wait for the cancel method to be called
+            fut = (
+                self.called_async.wait()
+                if use_async_cancel
+                else asyncio.get_running_loop().run_in_executor(
+                    None, self.called_non_async.wait
+                )
+            )
+            await asyncio.wait_for(fut, timeout=30)
+
+            # Release the workflow to complete
+            await caller_wf_handle.signal(CancelTestCallerWorkflow.release)
+
+            # Verify the workflow completed successfully
+            result = await caller_wf_handle.result()
+            assert result == "cancelled_successfully"