adds test example for hello_update.py

tests/hello/hello_update_test.py

@@ -0,0 +1,22 @@
+import uuid
+
+from temporalio.client import Client, WorkflowExecutionStatus
+from temporalio.worker import Worker
+
+from hello.hello_update import GreetingWorkflow
+
+
+async def test_signal_workflow(client: Client):
+    task_queue_name = str(uuid.uuid4())
+    async with Worker(client, task_queue=task_queue_name, workflows=[GreetingWorkflow]):
+        handle = await client.start_workflow(
+            GreetingWorkflow.run, id=str(uuid.uuid4()), task_queue=task_queue_name
+        )
+
+        assert WorkflowExecutionStatus.RUNNING == (await handle.describe()).status
+
+        update_result = await handle.execute_update(
+            GreetingWorkflow.update_workflow_status
+        )
+        assert "Workflow status updated" == update_result
+        assert WorkflowExecutionStatus.COMPLETED == (await handle.describe()).status