class RepositoryControllerTest extends \Silex\WebTestCase
{

    public function testGetAllAction()
    {
        $request = $this->getMock( 'Symfony\Component\HttpFoundation\Request' );

        $request = $this->getMock( 'Silex\Application' );
        $request->expects( $this->once() )
             ->method( 'offsetGet' ) // inside RepositoryController instead of $app['em'] use $app->offsetGet( 'em' )
             ->will( $this->returnValue( $this->getEntityManager() ) );
        $expected_results = json_encode( $you_know_this );

        $controller = new RepositoryController( $request, $app );

        $this->assertSame( $expected_results, $controller->getAllAction() );
   }
}