Method make_request_with_timeout

Lib/test/test_asyncio/test_tasks.py:600–662

(*, sleep: float, timeout: float)

        loop = asyncio.new_event_loop()

        async def make_request_with_timeout(*, sleep: float, timeout: float):
            task = self.current_task()
            loop = task.get_loop()

            timed_out = False
            structured_block_finished = False
            outer_code_reached = False

            def on_timeout():
                nonlocal timed_out
                timed_out = True
                task.cancel()

            timeout_handle = loop.call_later(timeout, on_timeout)
            try:
                try:
                    # Structured block affected by the timeout
                    await asyncio.sleep(sleep)
                    structured_block_finished = True
                finally:
                    timeout_handle.cancel()
                    if (
                        timed_out
                        and task.uncancel() == 0
                        and type(sys.exception()) is asyncio.CancelledError
                    ):
                        # Note the five rules that are needed here to satisfy proper
                        # uncancellation:
                        #
                        # 1. handle uncancellation in a `finally:` block to allow for
                        #    plain returns;
                        # 2. our `timed_out` flag is set, meaning that it was our event
                        #    that triggered the need to uncancel the task, regardless of
                        #    what exception is raised;
                        # 3. we can call `uncancel()` because *we* called `cancel()`
                        #    before;
                        # 4. we call `uncancel()` but we only continue converting the
                        #    CancelledError to TimeoutError if `uncancel()` caused the
                        #    cancellation request count go down to 0.  We need to look
                        #    at the counter vs having a simple boolean flag because our
                        #    code might have been nested (think multiple timeouts). See
                        #    commit 7fce1063b6e5a366f8504e039a8ccdd6944625cd for
                        #    details.
                        # 5. we only convert CancelledError to TimeoutError; for other
                        #    exceptions raised due to the cancellation (like
                        #    a ConnectionLostError from a database client), simply
                        #    propagate them.
                        #
                        # Those checks need to take place in this exact order to make
                        # sure the `cancelling()` counter always stays in sync.
                        #
                        # Additionally, the original stimulus to `cancel()` the task
                        # needs to be unscheduled to avoid re-cancelling the task later.
                        # Here we do it by cancelling `timeout_handle` in the `finally:`
                        # block.
                        raise TimeoutError
            except TimeoutError:
                self.assertTrue(timed_out)