code: def start(self):
      
      assert not self.watching
  
      def selector(evt):
        if evt.is_directory:
          return False
        path = evt.path
        if path in self._last_fnames: # Detected a "killing cycle"
          return False
        for pattern in self.skip_pattern.split(";"):
          if fnmatch(path, pattern.strip()):
            return False
        return True
  
      def watchdog_handler(evt):
        wx.CallAfter(self._watchdog_handler, evt)
  
      # Force a first event
      self._watching = True
      self._last_fnames = []
      self._evts = [None]
      self._run_subprocess()
  
      # Starts the watchdog observer
      from .watcher import watcher
      self._watcher = watcher(path=self.directory,
                              selector=selector, handler=watchdog_handler)
      self._watcher.__enter__()
docs: Starts watching the path and running the test jobs.