def run_for(self, duration):
self._run_for = max(self._run_for, float(duration))<EOL>
Run the test for a minimum number of seconds.

        Creates a test wide condition that becomes `valid` when the
        application under test has been running for `duration` seconds.
        Maybe be called multiple times, the test will run as long as the maximum value provided.

        Can be used to test applications without any externally visible
        streams, or streams that do not have testable conditions. For
        example a complete application may be tested by runnning it for
        for ten minutes and use :py:meth:`local_check` to test
        any external impacts, such as messages published to a
        message queue system.

        Args:
            duration(float): Minimum number of seconds the test will run for.

        .. versionadded: 1.9