public function seeFormErrorMessage($key, $expectedErrorMessage = null)
    {
        $viewErrorBag = $this->app['view']->shared('errors');

        if (!($viewErrorBag->has($key))) {
            $this->fail("No form error message for key '$key'\n");
        }

        if (! is_null($expectedErrorMessage)) {
            $this->assertStringContainsString($expectedErrorMessage, $viewErrorBag->first($key));
        }
    }