public function testEmailIsSentOnContact()
 {
     /** @var ContactForm $model */
     $this->model = $this->getMockBuilder('app\\models\\ContactForm')->setMethods(['validate'])->getMock();
     $this->model->expects($this->once())->method('validate')->will($this->returnValue(true));
     $this->model->attributes = ['name' => 'Tester', 'email' => '*****@*****.**', 'subject' => 'very important letter subject', 'body' => 'body of current message'];
     expect_that($this->model->contact('*****@*****.**'));
     // using Yii2 module actions to check email was sent
     $this->tester->seeEmailIsSent();
     $emailMessage = $this->tester->grabLastSentEmail();
     expect('valid email is sent', $emailMessage)->isInstanceOf('yii\\mail\\MessageInterface');
     expect($emailMessage->getTo())->hasKey('*****@*****.**');
     expect($emailMessage->getFrom())->hasKey('*****@*****.**');
     expect($emailMessage->getSubject())->equals('very important letter subject');
     expect($emailMessage->toString())->contains('body of current message');
 }