/**
  * @test
  */
 public function it_happend_to_an_activity()
 {
     $id = ActivityId::generate();
     $memberId = MemberId::generate();
     $event = new MemberRegisteredToParticipate($id, $memberId);
     $this->assertEquals($id, $event->activityId());
     $this->assertEquals($memberId, $event->memberId());
 }
 protected function applyMemberRegisteredToParticipate(MemberRegisteredToParticipate $event)
 {
     $this->members[] = $event->memberId();
 }