class FormDefaultHandlersTest

class FormDefaultHandlersTest extends KernelTestBase implements FormInterface {
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'test_form_handlers';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['#validate'][] = '::customValidateForm';
        $form['#submit'][] = '::customSubmitForm';
        $form['submit'] = [
            '#type' => 'submit',
            '#value' => 'Save',
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function customValidateForm(array &$form, FormStateInterface $form_state) {
        $test_handlers = $form_state->get('test_handlers');
        $test_handlers['validate'][] = __FUNCTION__;
        $form_state->set('test_handlers', $test_handlers);
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $test_handlers = $form_state->get('test_handlers');
        $test_handlers['validate'][] = __FUNCTION__;
        $form_state->set('test_handlers', $test_handlers);
    }
    
    /**
     * {@inheritdoc}
     */
    public function customSubmitForm(array &$form, FormStateInterface $form_state) {
        $test_handlers = $form_state->get('test_handlers');
        $test_handlers['submit'][] = __FUNCTION__;
        $form_state->set('test_handlers', $test_handlers);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $test_handlers = $form_state->get('test_handlers');
        $test_handlers['submit'][] = __FUNCTION__;
        $form_state->set('test_handlers', $test_handlers);
    }
    
    /**
     * Tests that default handlers are added even if custom are specified.
     */
    public function testDefaultAndCustomHandlers() {
        $form_state = new FormState();
        $form_builder = $this->container
            ->get('form_builder');
        $form_builder->submitForm($this, $form_state);
        $handlers = $form_state->get('test_handlers');
        $this->assertCount(2, $handlers['validate']);
        $this->assertSame('customValidateForm', $handlers['validate'][0]);
        $this->assertSame('validateForm', $handlers['validate'][1]);
        $this->assertCount(2, $handlers['submit']);
        $this->assertSame('customSubmitForm', $handlers['submit'][0]);
        $this->assertSame('submitForm', $handlers['submit'][1]);
    }

}