'L{server.Session.startCheckingExpiration} causes the session to expire
after L{server.Session.sessionTimeout} seconds without activity.'

def test_startCheckingExpiration(self):

    self.session.startCheckingExpiration()
    self.clock.advance((self.session.sessionTimeout - 1))
    self.assertIn(self.uid, self.site.sessions)
    self.clock.advance(1)
    self.assertNotIn(self.uid, self.site.sessions)
    self.assertFalse(self.clock.calls)
