protected function listen(EventEmitterInterface $emitter)
    {
        $emitter->on('suite.start', [$this, 'onSuiteStart']);
        $emitter->on('suite.end', [$this, 'onSuiteEnd']);
        $emitter->on('test.passed', [$this, 'onTestPassed']);
        $emitter->on('test.failed', [$this, 'onTestFailed']);
        $emitter->on('test.pending', [$this, 'onTestPending']);
        $emitter->on('suite.halt', [$this, 'onSuiteHalt']);
    }