ResponsiveImageStyle example

$this->entityTypeManager->expects($this->any())
      ->method('getStorage')
      ->with('image_style')
      ->willReturn($storage);

    $entity_type_repository = $this->getMockForAbstractClass(EntityTypeRepositoryInterface::class);
    $entity_type_repository->expects($this->any())
      ->method('getEntityTypeFromClass')
      ->with('Drupal\image\Entity\ImageStyle')
      ->willReturn('image_style');

    $entity = new ResponsiveImageStyle(['breakpoint_group' => 'test_group']);
    $entity->setBreakpointGroup('test_group');
    $entity->setFallbackImageStyle('fallback');
    $entity->addImageStyleMapping('test_breakpoint', '1x', ['image_mapping_type' => 'image_style', 'image_mapping' => 'small']);
    $entity->addImageStyleMapping('test_breakpoint', '2x', [
      'image_mapping_type' => 'sizes',
      'image_mapping' => [
        'sizes' => '(min-width:700px) 700px, 100vw',
        'sizes_image_styles' => [
          'medium' => 'medium',
          'large' => 'large',
        ],
      ],