60 lines
1.4 KiB
Python
60 lines
1.4 KiB
Python
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# Test the Task.remove_done_callback() method
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try:
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import asyncio
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except ImportError:
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print("SKIP")
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raise SystemExit
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async def task(t, exc=None):
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if t >= 0:
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await asyncio.sleep(t)
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if exc:
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raise exc
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def done_callback():
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print("done")
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def done_callback_2():
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print("done 2")
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async def main():
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# Removing a callback returns 0 when no callbacks have been set
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print("=" * 10)
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t = asyncio.create_task(task(1))
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print("Returns 0 when no done callback has been set:", t.remove_done_callback(done_callback))
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# Done callback removal only works once
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print("=" * 10)
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t = asyncio.create_task(task(1))
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t.add_done_callback(done_callback)
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print(
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"Returns 1 when a callback matches and is removed:", t.remove_done_callback(done_callback)
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)
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print(
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"Returns 0 on second attempt to remove the callback:",
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t.remove_done_callback(done_callback),
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)
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# Only removes done callback when match
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print("=" * 10)
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t = asyncio.create_task(task(0.01))
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t.add_done_callback(done_callback)
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print("Returns 0 when done callbacks don't match:", t.remove_done_callback(done_callback_2))
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# A removed done callback does not execute
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print("=" * 10)
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t = asyncio.create_task(task(-1))
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t.add_done_callback(done_callback)
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t.remove_done_callback(done_callback)
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print("Waiting for task to complete")
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await t
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print("Task completed")
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asyncio.run(main())
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