Python unit tests are non-deterministic

[chipkent]

Python unit tests use sleeps, which make them non-deterministic. For example:

    def test_snapshot_timetable(self):
        t = self.session.time_table(period=10000000)
        time.sleep(1)
        pa_table = t.snapshot()
        self.assertGreaterEqual(pa_table.num_rows, 1)

[jmao-denver]

had a discussion with @niloc132, he pointed out that the default refreshing period for time tables is 1s. So this test case definitely is not deterministic. One fix is to change the sleep time to 2s to make sure the time table refreshes at least once. @chipkent let me know what you think.

[chipkent]

Better to get @rcaudy 's thoughts.

[rcaudy]

My thoughts haven't changed since the last time we discussed something like this. Don't rely on sleeps to guarantee asynchronous behavior in unit tests.
There are exactly two ways forward for this test:

1. Use the existing UGP unit test support to control the refresh behavior, and thereby ensure that the TimeTable refreshes after the desired time has elapsed.
2. Delete this test. It seems to be trying to test the correct behavior of TimeTable, which is better done from Java on the engine side. You can test an initial value if you want, but it's not clear that this is a meaningful unit test for the Python wrapper.

[rcaudy]

Revising my comment. I thought this was a test for the server-side wrappers. On the client you don't have the option to control the server's UGP. The test should just be deleted, or revised to not expect data to tick.

[jmao-denver]

fixed by PR #1679