getImageStyleMapping example

$entity = new ResponsiveImageStyle(['']);
    $entity->addImageStyleMapping('test_breakpoint', '1x', [
      'image_mapping_type' => 'image_style',
      'image_mapping' => 'large',
    ]);
    $expected = [
      'breakpoint_id' => 'test_breakpoint',
      'multiplier' => '1x',
      'image_mapping_type' => 'image_style',
      'image_mapping' => 'large',
    ];
    $this->assertEquals($expected, $entity->getImageStyleMapping('test_breakpoint', '1x'));
    $this->assertNull($entity->getImageStyleMapping('test_unknown_breakpoint', '1x'));
  }

  /** * @covers ::addImageStyleMapping * @covers ::getKeyedImageStyleMappings */
  public function testGetKeyedImageStyleMappings() {
    $entity = new ResponsiveImageStyle(['']);
    $entity->addImageStyleMapping('test_breakpoint', '1x', [
      'image_mapping_type' => 'image_style',
      

    // width. For responsive images, we need largest breakpoint widths first, so     // we need to reverse the order of these breakpoints.     $breakpoints = array_reverse($this->breakpointManager->getBreakpointsByGroup($responsive_image_style->getBreakpointGroup()));

    foreach ($breakpoints as $breakpoint_id => $breakpoint) {
      foreach ($breakpoint->getMultipliers() as $multiplier) {
        $label = $multiplier . ' ' . $breakpoint->getLabel() . ' [' . $breakpoint->getMediaQuery() . ']';
        $form['keyed_styles'][$breakpoint_id][$multiplier] = [
          '#type' => 'details',
          '#title' => $label,
        ];
        $image_style_mapping = $responsive_image_style->getImageStyleMapping($breakpoint_id, $multiplier);
        if (\Drupal::moduleHandler()->moduleExists('help')) {
          $description = $this->t('See the <a href=":responsive_image_help">Responsive Image help page</a> for information on the sizes attribute.', [':responsive_image_help' => Url::fromRoute('help.page', ['name' => 'responsive_image'])->toString()]);
        }
        else {
          $description = $this->t('Enable the Help module for more information on the sizes attribute.');
        }
        $form['keyed_styles'][$breakpoint_id][$multiplier]['image_mapping_type'] = [
          '#title' => $this->t('Type'),
          '#type' => 'radios',
          '#options' => [
            'sizes' => $this->t('Select multiple image styles and use the sizes attribute.'),