def OnPrepare(self):
        if Choice(tm.main.tests_prepare_warning):
            for k in self.tests_list.CheckedStrings:
                self.report.AppendText(tm.main.tests_preparing.format(k))
                locals = {'mode': 'prepare'}
                ec = EnvironmentContext(None, locals)
                ec.ExecutePythonFile(os.path.join(self.tests_dir, k + '.py'))
            self.report.AppendText(tm.main.tests_preparing_done)