Q:

Mockery mock method inside closure

I have problem unit testing method inside closure called by call_user_func() example :
public function trans($lang, $callback)
{
   $this->sitepress->switch_lang($lang);
   call_user_func($callback);
}

on controller :
public function sendMail()
{
   $foo = $baz = 'something';
   $mail = $this->mailer;
   $this->helper->trans_c('en', function() use($foo, $baz, $mail) {
      $mail->send('Subject', $foo, $baz);
   });
}

test case :
public function testSomething()
{
   $helperMock = Mockery::mock('Acme\Helper');
   $helperMock->shouldReceive('trans_c')->once(); // passed

   $mailMock = Mockery::mock('Acme\Mail');
   $mailMock->shouldReceive('send')->once(); // got should be called 1 times instead 0

   $act = new SendMailController($helperMock, $mailMock);
   $act->sendMail();
}

how can I ensure that ->send() method is called inside closure trans_c()
I tried with
$helperMock->shouldReceive('trans_c')->with('en', function() use($mailMock) {
   $mailMock->shouldReceive('send');
});

no luck. :( 
well it works fine with passing Mockery::type('Closure') in the second param of trans_c, but I really need to ensure that method send from mailer class is called. 

A:

A mocked class does not execute the real code by default.  If you mock the helper it will check that the calls are being made but won't execute the anonymous function. 
With mockery, you can configure the expectation so that the real method will be executed: passthru();
Try this:
$helperMock = Mockery::mock('Acme\Helper');
$helperMock
     ->shouldReceive('trans_c')
     ->once()
     ->passthru()
;

This is explained in the docs. 
EDIT
Maybe you don't really need to mock the helper.  If you mock the Mail class and expect the send method to be called once, just let the real helper do it.