tests/extmod/asyncio_wait_task.py: Add test for raise and delayed wait.

This case was fixed in 2ecbad4e91192c88f831d8690dbad31ddba72135, which
stored the exception in the task object.

Signed-off-by: Damien George <damien@micropython.org>

tests/extmod/asyncio_wait_task.py

@@ -68,5 +68,16 @@ async def main():
     except ValueError:
         print("ValueError")
 
+    # Wait on a task that raises, but the waiting is done some time later.
+    # Need to suppress the "Task exception wasn't retrieved" message.
+    asyncio.get_event_loop().set_exception_handler(lambda loop, context: None)
+    t = asyncio.create_task(task_raise())
+    for _ in range(5):
+        await asyncio.sleep(0)
+    try:
+        await t
+    except ValueError:
+        print("ValueError")
+
 
 asyncio.run(main())

tests/extmod/asyncio_wait_task.py.exp

@@ -8,3 +8,5 @@ world
 took 200 200
 task_raise
 ValueError
+task_raise
+ValueError