test: add tests for new task result and exception behavior

Author: imnotjames

tests/extmod/asyncio_task_cancelled.py

@@ -0,0 +1,54 @@
+# Test cancelling a task
+
+try:
+    import asyncio
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+async def task(t):
+    await asyncio.sleep(t)
+
+
+async def main():
+    # Cancel task immediately doesn't mark the task as cancelled
+    print("=" * 10)
+    t = asyncio.create_task(task(2))
+    t.cancel()
+    print("Expecting task to not be cancelled because it is not done:", t.cancelled())
+
+    # Cancel task immediately and wait for cancellation to complete
+    print("=" * 10)
+    t = asyncio.create_task(task(2))
+    t.cancel()
+    await asyncio.sleep(0)
+    print("Expecting Task to be Cancelled:", t.cancelled())
+
+    # Cancel task and wait for cancellation to complete
+    print("=" * 10)
+    t = asyncio.create_task(task(2))
+    await asyncio.sleep(0.01)
+    t.cancel()
+    await asyncio.sleep(0)
+    print("Expecting Task to be Cancelled:", t.cancelled())
+
+    # Cancel task multiple times after it has started
+    print("=" * 10)
+    t = asyncio.create_task(task(2))
+    await asyncio.sleep(0.01)
+    for _ in range(4):
+        t.cancel()
+    await asyncio.sleep(0.01)
+
+    print("Expecting Task to be Cancelled:", t.cancelled())
+
+    # Cancel task after it has finished
+    print("=" * 10)
+    t = asyncio.create_task(task(0.01))
+    await asyncio.sleep(0.05)
+    t.cancel()
+    print("Expecting task to not be Cancelled:", t.cancelled())
+
+
+asyncio.run(main())

tests/extmod/asyncio_task_cancelled.py.exp

@@ -0,0 +1,10 @@
+==========
+Expecting task to not be cancelled because it is not done: False
+==========
+Expecting Task to be Cancelled: True
+==========
+Expecting Task to be Cancelled: True
+==========
+Expecting Task to be Cancelled: True
+==========
+Expecting task to not be Cancelled: False

tests/extmod/asyncio_task_exception.py

@@ -0,0 +1,57 @@
+# Test the Task.done() method
+
+try:
+    import asyncio
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+async def task(t, exc=None):
+    if t >= 0:
+        await asyncio.sleep(t)
+    if exc:
+        raise exc
+
+
+async def main():
+    # Task that is not done yet raises an InvalidStateError
+    print("=" * 10)
+    t = asyncio.create_task(task(1))
+    await asyncio.sleep(0)
+    try:
+        t.exception()
+        assert False, "Should not get here"
+    except Exception as e:
+        print("Tasks that aren't done yet raise an InvalidStateError:", repr(e))
+
+    # Task that is cancelled raises CancelledError
+    print("=" * 10)
+    t = asyncio.create_task(task(1))
+    t.cancel()
+    await asyncio.sleep(0)
+    try:
+        print(repr(t.exception()))
+        print(t.cancelled())
+        assert False, "Should not get here"
+    except asyncio.CancelledError as e:
+        print("Cancelled tasks cannot retrieve exception:", repr(e))
+
+    # Task that starts, runs and finishes without an exception should return None
+    print("=" * 10)
+    t = asyncio.create_task(task(0.01))
+    await t
+    print("None when no exception:", t.exception())
+
+    # Task that raises immediately should return that exception
+    print("=" * 10)
+    t = asyncio.create_task(task(-1, ValueError))
+    try:
+        await t
+        assert False, "Should not get here"
+    except ValueError as e:
+        pass
+    print("Returned Exception:", repr(t.exception()))
+
+
+asyncio.run(main())

tests/extmod/asyncio_task_exception.py.exp

@@ -0,0 +1,8 @@
+==========
+Tasks that aren't done yet raise an InvalidStateError: InvalidStateError('Exception is not set.',)
+==========
+Cancelled tasks cannot retrieve exception: CancelledError()
+==========
+None when no exception: None
+==========
+Returned Exception: ValueError()

tests/extmod/asyncio_task_result.py

@@ -0,0 +1,69 @@
+# Test the Task.done() method
+
+try:
+    import asyncio
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+async def task(t, exc=None, ret=None):
+    if t >= 0:
+        await asyncio.sleep(t)
+    if exc:
+        raise exc
+    return ret
+
+
+async def main():
+    # Task that is not done yet raises an InvalidStateError
+    print("=" * 10)
+    t = asyncio.create_task(task(1))
+    await asyncio.sleep(0)
+    try:
+        t.result()
+        assert False, "Should not get here"
+    except Exception as e:
+        print("InvalidStateError if still running:", repr(e))
+
+    # Task that is cancelled raises CancelledError
+    print("=" * 10)
+    t = asyncio.create_task(task(1))
+    t.cancel()
+    await asyncio.sleep(0)
+    try:
+        t.result()
+        assert False, "Should not get here"
+    except asyncio.CancelledError as e:
+        print("CancelledError when retrieving result from cancelled task:", repr(e))
+
+    # Task that raises immediately should raise that exception when calling result
+    print("=" * 10)
+    t = asyncio.create_task(task(-1, ValueError))
+    try:
+        await t
+        assert False, "Should not get here"
+    except ValueError as e:
+        pass
+
+    try:
+        t.result()
+        assert False, "Should not get here"
+    except ValueError as e:
+        print("Error raised when result is attempted on task with error:", repr(e))
+
+    # Task that starts, runs and finishes without an exception or value should return None
+    print("=" * 10)
+    t = asyncio.create_task(task(0.01))
+    await t
+    print("Empty Result should be None:", t.result())
+    assert t.result() is None
+
+    # Task that starts, runs and finishes without exception should return result
+    print("=" * 10)
+    t = asyncio.create_task(task(0.01, None, "hello world"))
+    await t
+    print("Happy path, result is returned:", t.result())
+
+
+asyncio.run(main())

tests/extmod/asyncio_task_result.py.exp

@@ -0,0 +1,10 @@
+==========
+InvalidStateError if still running: InvalidStateError('Result is not ready.',)
+==========
+CancelledError when retrieving result from cancelled task: CancelledError()
+==========
+Error raised when result is attempted on task with error: ValueError()
+==========
+Empty Result should be None: None
+==========
+Happy path, result is returned: hello world