Aacotroneo\Saml2\Saml2Auth::login PHP Method

    function login($returnTo = null)
    {
        $auth = $this->auth;
        $auth->login($returnTo);
    }

 public function testLogin()
 {
     $auth = m::mock('OneLogin_Saml2_Auth');
     $saml2 = new Saml2Auth($auth);
     $auth->shouldReceive('login')->once();
     $saml2->login();
 }