Class TestLoop

Lib/test/test_asyncio/utils.py:331–493

Loop for unittests. It manages self time directly. If something scheduled to be executed later then on next loop iteration after all ready handlers done generator passed to __init__ is calling. Generator should be like this: def gen(): ... when

class TestLoop(base_events.BaseEventLoop):
    """Loop for unittests.

    It manages self time directly.
    If something scheduled to be executed later then
    on next loop iteration after all ready handlers done
    generator passed to __init__ is calling.

    Generator should be like this:

        def gen():
            ...
            when = yield ...
            ... = yield time_advance

    Value returned by yield is absolute time of next scheduled handler.
    Value passed to yield is time advance to move loop's time forward.
    """

    def __init__(self, gen=None):
        super().__init__()

        if gen is None:
            def gen():
                yield
            self._check_on_close = False
        else:
            self._check_on_close = True

        self._gen = gen()
        next(self._gen)
        self._time = 0
        self._clock_resolution = 1e-9
        self._timers = []
        self._selector = TestSelector()

        self.readers = {}
        self.writers = {}
        self.reset_counters()

        self._transports = weakref.WeakValueDictionary()

    def time(self):
        return self._time

    def advance_time(self, advance):
        """Move test time forward."""
        if advance:
            self._time += advance

    def close(self):
        super().close()
        if self._check_on_close:
            try:
                self._gen.send(0)
            except StopIteration:
                pass
            else:  # pragma: no cover