How to test broadcast driver?

It's an old question, but just in case it can help someone : i did for myself an assert function that you should add to your TestCase.php.

The idea is to set the broadcast driver to "log" and then to read the 4th line from the end to see if it's a broadcast log.

In your phpunit.xml

Add the folowing line to the node:

<env name="BROADCAST_DRIVER" value="log"/>

In your TestCase.php file

Add the folowing function :

public function assertEventIsBroadcasted($eventClassName, $channel=""){
  $logfileFullpath = storage_path("logs/laravel.log");
  $logfile = explode("\n", file_get_contents($logfileFullpath));

  if(count($logfile) > 4){
    $supposedLastEventLogged = $logfile[count($logfile)-5];

    $this->assertContains("Broadcasting [", $supposedLastEventLogged, "No broadcast were found.\n");

    $this->assertContains("Broadcasting [".$eventClassName."]", $supposedLastEventLogged, "A broadcast was found, but not for the classname '".$eventClassName."'.\n");

    if($channel != "")
      $this->assertContains("Broadcasting [".$eventClassName."] on channels [".$channel."]", $supposedLastEventLogged, "The expected broadcast (".$eventClassName.") event was found, but not on the expected channel '".$channel."'.\n");
  }else{
    $this->fail("No informations found in the file log '".$logfileFullpath."'.");
  }
}

Instead of checking what's written in log, you can to use the assertion 'expectsEvents', which you can test if a certain event is launched.

public function testMethod(){
   $this->expectsEvents(YourEventClass::class)
    ...your code test...
}

For more info: https://laravel-guide.readthedocs.io/en/latest/mocking/