class DependentDropdownTest

class DependentDropdownTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    public static $modules = [
        'ajax_example',
    ];
    
    /**
     * Test the dependent dropdown form without AJAX.
     */
    public function testDependentDropdown() {
        // Get the Mink stuff.
        $session = $this->getSession();
        $assert = $this->assertSession();
        $page = $session->getPage();
        // Get a URL object for the form, specifying no JS.
        $dropdown_url = Url::fromRoute('ajax_example.dependent_dropdown', [
            'nojs' => 'nojs',
        ]);
        // Get the form.
        $this->drupalGet($dropdown_url);
        // Check for the initial state.
        $assert->fieldDisabled('instrument_dropdown');
        $assert->fieldValueEquals('instrument_dropdown', 'none');
        $submit_button = $page->findButton('edit-submit');
        $this->assertTrue($submit_button->hasAttribute('disabled'));
        // Run through the matrix of form submissions.
        $families = [
            'String' => [
                'Violin',
                'Viola',
                'Cello',
                'Double Bass',
            ],
            'Woodwind' => [
                'Flute',
                'Clarinet',
                'Oboe',
                'Bassoon',
            ],
            'Brass' => [
                'Trumpet',
                'Trombone',
                'French Horn',
                'Euphonium',
            ],
            'Percussion' => [
                'Bass Drum',
                'Timpani',
                'Snare Drum',
                'Tambourine',
            ],
        ];
        foreach ($families as $family => $instruments) {
            // Post the form for the instrument family.
            $this->drupalPostForm($dropdown_url, [
                'instrument_family_dropdown' => $family,
            ], 'Choose');
            // Get the instrument dropdown elements.
            $instrument_options = $page->findAll('css', '#edit-instrument-dropdown option');
            $this->assertCount(count($instruments), $instrument_options);
            // Make sure all the instruments are in the select dropdown.
            foreach ($instrument_options as $instrument) {
                $this->assertContains($instrument->getAttribute('value'), $instruments);
            }
            // Post each instrument. We have to 'choose' again in order to unlock the
            // instrument dropdown.
            foreach ($instruments as $instrument) {
                $this->drupalPostForm($dropdown_url, [
                    'instrument_family_dropdown' => $family,
                ], 'Choose');
                $this->drupalPostForm(NULL, [
                    'instrument_dropdown' => $instrument,
                ], 'Submit');
                $assert->pageTextContains("Your values have been submitted. Instrument family: {$family}, Instrument: {$instrument}");
            }
        }
    }

}