BubbleableMetadataTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\Core\Render;

use Drupal\Core\Cache\Cache;
use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Render\BubbleableMetadata;
use Drupal\Tests\UnitTestCase;
use Symfony\Component\DependencyInjection\ContainerBuilder;

/**
 * @coversDefaultClass \Drupal\Core\Render\BubbleableMetadata
 * @group Render
 */
class BubbleableMetadataTest extends UnitTestCase {
    
    /**
     * Tests merge().
     *
     * This only tests at a high level, because it reuses existing logic. Detailed
     * tests exist for the existing logic:
     *
     * @see \Drupal\Tests\Core\Cache\CacheTest::testMergeTags()
     * @see \Drupal\Tests\Core\Cache\CacheTest::testMergeMaxAges()
     * @see \Drupal\Tests\Core\Cache\CacheContextsTest
     * @see \Drupal\Tests\Core\Render\RendererPlaceholdersTest
     * @see testMergeAttachmentsLibraryMerging()
     * @see testMergeAttachmentsFeedMerging()
     * @see testMergeAttachmentsHtmlHeadMerging()
     * @see testMergeAttachmentsHtmlHeadLinkMerging()
     * @see testMergeAttachmentsHttpHeaderMerging()
     *
     * @covers ::merge
     * @dataProvider providerTestMerge
     */
    public function testMerge(BubbleableMetadata $a, CacheableMetadata $b, BubbleableMetadata $expected) : void {
        // Verify that if the second operand is a CacheableMetadata object, not a
        // BubbleableMetadata object, that BubbleableMetadata::merge() doesn't
        // attempt to merge assets.
        if (!$b instanceof BubbleableMetadata) {
            $renderer = $this->getMockBuilder('Drupal\\Core\\Render\\Renderer')
                ->disableOriginalConstructor()
                ->getMock();
        }
        else {
            $renderer = $this->getMockBuilder('Drupal\\Core\\Render\\Renderer')
                ->disableOriginalConstructor()
                ->onlyMethods([])
                ->getMock();
        }
        $cache_contexts_manager = $this->getMockBuilder('Drupal\\Core\\Cache\\Context\\CacheContextsManager')
            ->disableOriginalConstructor()
            ->getMock();
        $cache_contexts_manager->method('assertValidTokens')
            ->willReturn(TRUE);
        $container = new ContainerBuilder();
        $container->set('cache_contexts_manager', $cache_contexts_manager);
        $container->set('renderer', $renderer);
        \Drupal::setContainer($container);
        $this->assertEqualsCanonicalizing($expected, $a->merge($b));
    }
    
    /**
     * Provides test data for testMerge().
     *
     * @return array
     */
    public static function providerTestMerge() {
        return [
            // Second operand is a BubbleableMetadata object.
            // All empty.
[
                new BubbleableMetadata(),
                new BubbleableMetadata(),
                new BubbleableMetadata(),
            ],
            // Cache contexts.
[
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                ]),
                (new BubbleableMetadata())->setCacheContexts([
                    'bar',
                ]),
                (new BubbleableMetadata())->setCacheContexts([
                    'bar',
                    'foo',
                ]),
            ],
            // Cache tags.
[
                (new BubbleableMetadata())->setCacheTags([
                    'foo',
                ]),
                (new BubbleableMetadata())->setCacheTags([
                    'bar',
                ]),
                (new BubbleableMetadata())->setCacheTags([
                    'foo',
                    'bar',
                ]),
            ],
            // Cache max-ages.
[
                (new BubbleableMetadata())->setCacheMaxAge(60),
                (new BubbleableMetadata())->setCacheMaxAge(Cache::PERMANENT),
                (new BubbleableMetadata())->setCacheMaxAge(60),
            ],
            // Assets.
[
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/foo',
                    ],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/bar',
                    ],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/foo',
                        'core/bar',
                    ],
                ]),
            ],
            // Placeholders.
[
                (new BubbleableMetadata())->setAttachments([
                    'placeholders' => [
                        '<my-placeholder>' => [
                            'callback',
                            [
                                'A',
                            ],
                        ],
                    ],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'placeholders' => [
                        '<my-placeholder>' => [
                            'callback',
                            [
                                'A',
                            ],
                        ],
                    ],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'placeholders' => [
                        '<my-placeholder>' => [
                            'callback',
                            [
                                'A',
                            ],
                        ],
                    ],
                ]),
            ],
            // Second operand is a CacheableMetadata object.
            // All empty.
[
                new BubbleableMetadata(),
                new CacheableMetadata(),
                new BubbleableMetadata(),
            ],
            // Cache contexts.
[
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                ]),
                (new CacheableMetadata())->setCacheContexts([
                    'bar',
                ]),
                (new BubbleableMetadata())->setCacheContexts([
                    'bar',
                    'foo',
                ]),
            ],
            // Cache tags.
[
                (new BubbleableMetadata())->setCacheTags([
                    'foo',
                ]),
                (new CacheableMetadata())->setCacheTags([
                    'bar',
                ]),
                (new BubbleableMetadata())->setCacheTags([
                    'foo',
                    'bar',
                ]),
            ],
            // Cache max-ages.
[
                (new BubbleableMetadata())->setCacheMaxAge(60),
                (new CacheableMetadata())->setCacheMaxAge(Cache::PERMANENT),
                (new BubbleableMetadata())->setCacheMaxAge(60),
            ],
        ];
    }
    
    /**
     * Tests addAttachments().
     *
     * This only tests at a high level, because it reuses existing logic. Detailed
     * tests exist for the existing logic:
     *
     * @see testMergeAttachmentsLibraryMerging()
     * @see testMergeAttachmentsFeedMerging()
     * @see testMergeAttachmentsHtmlHeadMerging()
     * @see testMergeAttachmentsHtmlHeadLinkMerging()
     * @see testMergeAttachmentsHttpHeaderMerging()
     *
     * @covers ::addAttachments
     * @covers ::setAttachments
     * @dataProvider providerTestAddAttachments
     */
    public function testAddAttachments(BubbleableMetadata $initial, $attachments, BubbleableMetadata $expected) : void {
        $test = $initial;
        $test->addAttachments($attachments);
        $this->assertEquals($expected, $test);
    }
    
    /**
     * Provides test data for testAddAttachments().
     */
    public static function providerTestAddAttachments() {
        return [
            [
                new BubbleableMetadata(),
                [],
                new BubbleableMetadata(),
            ],
            [
                new BubbleableMetadata(),
                [
                    'library' => [
                        'core/foo',
                    ],
                ],
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/foo',
                    ],
                ]),
            ],
            [
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/foo',
                    ],
                ]),
                [
                    'library' => [
                        'core/bar',
                    ],
                ],
                (new BubbleableMetadata())->setAttachments([
                    'library' => [
                        'core/foo',
                        'core/bar',
                    ],
                ]),
            ],
        ];
    }
    
    /**
     * @covers ::applyTo
     * @dataProvider providerTestApplyTo
     */
    public function testApplyTo(BubbleableMetadata $metadata, array $render_array, array $expected) : void {
        $this->assertNull($metadata->applyTo($render_array));
        $this->assertEquals($expected, $render_array);
    }
    
    /**
     * Provides test data for testApplyTo().
     *
     * @return array
     */
    public static function providerTestApplyTo() {
        $data = [];
        $empty_metadata = new BubbleableMetadata();
        $nonempty_metadata = new BubbleableMetadata();
        $nonempty_metadata->setCacheContexts([
            'qux',
        ])
            ->setCacheTags([
            'foo:bar',
        ])
            ->setAttachments([
            'settings' => [
                'foo' => 'bar',
            ],
        ]);
        $empty_render_array = [];
        $nonempty_render_array = [
            '#cache' => [
                'contexts' => [
                    'qux',
                ],
                'tags' => [
                    'llamas:are:awesome:but:kittens:too',
                ],
                'max-age' => Cache::PERMANENT,
            ],
            '#attached' => [
                'library' => [
                    'core/jquery',
                ],
            ],
        ];
        $expected_when_empty_metadata = [
            '#cache' => [
                'contexts' => [],
                'tags' => [],
                'max-age' => Cache::PERMANENT,
            ],
            '#attached' => [],
        ];
        $data[] = [
            $empty_metadata,
            $empty_render_array,
            $expected_when_empty_metadata,
        ];
        $data[] = [
            $empty_metadata,
            $nonempty_render_array,
            $expected_when_empty_metadata,
        ];
        $expected_when_nonempty_metadata = [
            '#cache' => [
                'contexts' => [
                    'qux',
                ],
                'tags' => [
                    'foo:bar',
                ],
                'max-age' => Cache::PERMANENT,
            ],
            '#attached' => [
                'settings' => [
                    'foo' => 'bar',
                ],
            ],
        ];
        $data[] = [
            $nonempty_metadata,
            $empty_render_array,
            $expected_when_nonempty_metadata,
        ];
        $data[] = [
            $nonempty_metadata,
            $nonempty_render_array,
            $expected_when_nonempty_metadata,
        ];
        return $data;
    }
    
    /**
     * @covers ::createFromRenderArray
     * @dataProvider providerTestCreateFromRenderArray
     */
    public function testCreateFromRenderArray(array $render_array, BubbleableMetadata $expected) : void {
        $this->assertEquals($expected, BubbleableMetadata::createFromRenderArray($render_array));
    }
    
    /**
     * Provides test data for createFromRenderArray().
     *
     * @return array
     */
    public static function providerTestCreateFromRenderArray() {
        $data = [];
        $empty_metadata = new BubbleableMetadata();
        $nonempty_metadata = new BubbleableMetadata();
        $nonempty_metadata->setCacheContexts([
            'qux',
        ])
            ->setCacheTags([
            'foo:bar',
        ])
            ->setAttachments([
            'settings' => [
                'foo' => 'bar',
            ],
        ]);
        $empty_render_array = [];
        $nonempty_render_array = [
            '#cache' => [
                'contexts' => [
                    'qux',
                ],
                'tags' => [
                    'foo:bar',
                ],
                'max-age' => Cache::PERMANENT,
            ],
            '#attached' => [
                'settings' => [
                    'foo' => 'bar',
                ],
            ],
        ];
        $data[] = [
            $empty_render_array,
            $empty_metadata,
        ];
        $data[] = [
            $nonempty_render_array,
            $nonempty_metadata,
        ];
        return $data;
    }
    
    /**
     * Tests library asset merging.
     *
     * @covers ::mergeAttachments
     */
    public function testMergeAttachmentsLibraryMerging() : void {
        $a['#attached'] = [
            'library' => [
                'core/drupal',
                'core/drupalSettings',
            ],
            'drupalSettings' => [
                'foo' => [
                    'd',
                ],
            ],
        ];
        $b['#attached'] = [
            'library' => [
                'core/jquery',
            ],
            'drupalSettings' => [
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
            ],
        ];
        $expected['#attached'] = [
            'library' => [
                'core/drupal',
                'core/drupalSettings',
                'core/jquery',
            ],
            'drupalSettings' => [
                'foo' => [
                    'd',
                ],
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
            ],
        ];
        $this->assertSame($expected['#attached'], BubbleableMetadata::mergeAttachments($a['#attached'], $b['#attached']), 'Attachments merged correctly.');
        // Merging in the opposite direction yields the opposite library order.
        $expected['#attached'] = [
            'library' => [
                'core/jquery',
                'core/drupal',
                'core/drupalSettings',
            ],
            'drupalSettings' => [
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
                'foo' => [
                    'd',
                ],
            ],
        ];
        $this->assertSame($expected['#attached'], BubbleableMetadata::mergeAttachments($b['#attached'], $a['#attached']), 'Attachments merged correctly; opposite merging yields opposite order.');
        // Merging with duplicates: duplicates are simply retained, it's up to the
        // rest of the system to handle duplicates.
        $b['#attached']['library'][] = 'core/drupalSettings';
        $expected['#attached'] = [
            'library' => [
                'core/drupal',
                'core/drupalSettings',
                'core/jquery',
                'core/drupalSettings',
            ],
            'drupalSettings' => [
                'foo' => [
                    'd',
                ],
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
            ],
        ];
        $this->assertSame($expected['#attached'], BubbleableMetadata::mergeAttachments($a['#attached'], $b['#attached']), 'Attachments merged correctly; duplicates are retained.');
        // Merging with duplicates (simple case).
        $b['#attached']['drupalSettings']['foo'] = [
            'a',
            'b',
            'c',
        ];
        $expected['#attached'] = [
            'library' => [
                'core/drupal',
                'core/drupalSettings',
                'core/jquery',
                'core/drupalSettings',
            ],
            'drupalSettings' => [
                'foo' => [
                    'a',
                    'b',
                    'c',
                ],
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
            ],
        ];
        $this->assertSame($expected['#attached'], BubbleableMetadata::mergeAttachments($a['#attached'], $b['#attached']));
        // Merging with duplicates (simple case) in the opposite direction yields
        // the opposite JS setting asset order, but also opposite overriding order.
        $expected['#attached'] = [
            'library' => [
                'core/jquery',
                'core/drupalSettings',
                'core/drupal',
                'core/drupalSettings',
            ],
            'drupalSettings' => [
                'bar' => [
                    'a',
                    'b',
                    'c',
                ],
                'foo' => [
                    'd',
                    'b',
                    'c',
                ],
            ],
        ];
        $this->assertSame($expected['#attached'], BubbleableMetadata::mergeAttachments($b['#attached'], $a['#attached']));
        // Merging with duplicates: complex case.
        // Only the second of these two entries should appear in drupalSettings.
        $build = [];
        $build['a']['#attached']['drupalSettings']['commonTest'] = 'firstValue';
        $build['b']['#attached']['drupalSettings']['commonTest'] = 'secondValue';
        // Only the second of these entries should appear in drupalSettings.
        $build['a']['#attached']['drupalSettings']['commonTestJsArrayLiteral'] = [
            'firstValue',
        ];
        $build['b']['#attached']['drupalSettings']['commonTestJsArrayLiteral'] = [
            'secondValue',
        ];
        // Only the second of these two entries should appear in drupalSettings.
        $build['a']['#attached']['drupalSettings']['commonTestJsObjectLiteral'] = [
            'key' => 'firstValue',
        ];
        $build['b']['#attached']['drupalSettings']['commonTestJsObjectLiteral'] = [
            'key' => 'secondValue',
        ];
        // Real world test case: multiple elements in a render array are adding the
        // same (or nearly the same) JavaScript settings. When merged, they should
        // contain all settings and not duplicate some settings.
        $settings_one = [
            'moduleName' => [
                'ui' => [
                    'button A',
                    'button B',
                ],
                'magical flag' => 3.14159265359,
            ],
        ];
        $build['a']['#attached']['drupalSettings']['commonTestRealWorldIdentical'] = $settings_one;
        $build['b']['#attached']['drupalSettings']['commonTestRealWorldIdentical'] = $settings_one;
        $settings_two_a = [
            'moduleName' => [
                'ui' => [
                    'button A',
                    'button B',
                    'button C',
                ],
                'magical flag' => 3.14159265359,
                'thingiesOnPage' => [
                    'id1' => [],
                ],
            ],
        ];
        $build['a']['#attached']['drupalSettings']['commonTestRealWorldAlmostIdentical'] = $settings_two_a;
        $settings_two_b = [
            'moduleName' => [
                'ui' => [
                    'button D',
                    'button E',
                ],
                'magical flag' => 3.14,
                'thingiesOnPage' => [
                    'id2' => [],
                ],
            ],
        ];
        $build['b']['#attached']['drupalSettings']['commonTestRealWorldAlmostIdentical'] = $settings_two_b;
        $merged = BubbleableMetadata::mergeAttachments($build['a']['#attached'], $build['b']['#attached']);
        // Test whether #attached can be used to override a previous setting.
        $this->assertSame('secondValue', $merged['drupalSettings']['commonTest']);
        // Test whether #attached can be used to add and override a JavaScript
        // array literal (an indexed PHP array) values.
        $this->assertSame('secondValue', $merged['drupalSettings']['commonTestJsArrayLiteral'][0]);
        // Test whether #attached can be used to add and override a JavaScript
        // object literal (an associate PHP array) values.
        $this->assertSame('secondValue', $merged['drupalSettings']['commonTestJsObjectLiteral']['key']);
        // Test whether the two real world cases are handled correctly: the first
        // adds the exact same settings twice and hence tests idempotency, the
        // second adds *almost* the same settings twice: the second time, some
        // values are altered, and some key-value pairs are added.
        $this->assertSame($settings_one, $merged['drupalSettings']['commonTestRealWorldIdentical']);
        $expected_settings_two = $settings_two_a;
        $expected_settings_two['moduleName']['thingiesOnPage']['id1'] = [];
        $expected_settings_two['moduleName']['ui'][0] = 'button D';
        $expected_settings_two['moduleName']['ui'][1] = 'button E';
        $expected_settings_two['moduleName']['ui'][2] = 'button C';
        $expected_settings_two['moduleName']['magical flag'] = 3.14;
        $expected_settings_two['moduleName']['thingiesOnPage']['id2'] = [];
        $this->assertSame($expected_settings_two, $merged['drupalSettings']['commonTestRealWorldAlmostIdentical']);
    }
    
    /**
     * Tests html_head asset merging.
     *
     * @covers ::mergeAttachments
     *
     * @dataProvider providerTestMergeAttachmentsHtmlHeadMerging
     */
    public function testMergeAttachmentsHtmlHeadMerging($a, $b, $expected) : void {
        $this->assertSame($expected, BubbleableMetadata::mergeAttachments($a, $b));
    }
    
    /**
     * Data provider for testMergeAttachmentsHtmlHeadMerging.
     *
     * @return array
     */
    public static function providerTestMergeAttachmentsHtmlHeadMerging() {
        $meta = [
            '#tag' => 'meta',
            '#attributes' => [
                'charset' => 'utf-8',
            ],
            '#weight' => -1000,
        ];
        $html_tag = [
            '#type' => 'html_tag',
            '#tag' => 'meta',
            '#attributes' => [
                'name' => 'Generator',
                'content' => 'Kitten 1.0 (https://www.drupal.org/project/kitten)',
            ],
        ];
        $a = [
            'html_head' => [
                $meta,
                'system_meta_content_type',
            ],
        ];
        $b = [
            'html_head' => [
                $html_tag,
                'system_meta_generator',
            ],
        ];
        $expected_a = [
            'html_head' => [
                $meta,
                'system_meta_content_type',
                $html_tag,
                'system_meta_generator',
            ],
        ];
        // Merging in the opposite direction yields the opposite library order.
        $expected_b = [
            'html_head' => [
                $html_tag,
                'system_meta_generator',
                $meta,
                'system_meta_content_type',
            ],
        ];
        return [
            [
                $a,
                $b,
                $expected_a,
            ],
            [
                $b,
                $a,
                $expected_b,
            ],
        ];
    }
    
    /**
     * Tests html_head_link asset merging.
     *
     * @covers ::mergeAttachments
     *
     * @dataProvider providerTestMergeAttachmentsHtmlHeadLinkMerging
     */
    public function testMergeAttachmentsHtmlHeadLinkMerging($a, $b, $expected) : void {
        $this->assertSame($expected, BubbleableMetadata::mergeAttachments($a, $b));
    }
    
    /**
     * Data provider for testMergeAttachmentsHtmlHeadLinkMerging.
     *
     * @return array
     */
    public static function providerTestMergeAttachmentsHtmlHeadLinkMerging() {
        $rel = [
            'rel' => 'rel',
            'href' => 'http://rel.example.com',
        ];
        $shortlink = [
            'rel' => 'shortlink',
            'href' => 'http://shortlink.example.com',
        ];
        $a = [
            'html_head_link' => [
                $rel,
                TRUE,
            ],
        ];
        $b = [
            'html_head_link' => [
                $shortlink,
                FALSE,
            ],
        ];
        $expected_a = [
            'html_head_link' => [
                $rel,
                TRUE,
                $shortlink,
                FALSE,
            ],
        ];
        // Merging in the opposite direction yields the opposite library order.
        $expected_b = [
            'html_head_link' => [
                $shortlink,
                FALSE,
                $rel,
                TRUE,
            ],
        ];
        return [
            [
                $a,
                $b,
                $expected_a,
            ],
            [
                $b,
                $a,
                $expected_b,
            ],
        ];
    }
    
    /**
     * Tests http_header asset merging.
     *
     * @covers ::mergeAttachments
     *
     * @dataProvider providerTestMergeAttachmentsHttpHeaderMerging
     */
    public function testMergeAttachmentsHttpHeaderMerging($a, $b, $expected) : void {
        $this->assertSame($expected, BubbleableMetadata::mergeAttachments($a, $b));
    }
    
    /**
     * Data provider for testMergeAttachmentsHttpHeaderMerging.
     *
     * @return array
     */
    public static function providerTestMergeAttachmentsHttpHeaderMerging() {
        $content_type = [
            'Content-Type',
            'application/rss+xml; charset=utf-8',
        ];
        $expires = [
            'Expires',
            'Sun, 19 Nov 1978 05:00:00 GMT',
        ];
        $a = [
            'http_header' => [
                $content_type,
            ],
        ];
        $b = [
            'http_header' => [
                $expires,
            ],
        ];
        $expected_a = [
            'http_header' => [
                $content_type,
                $expires,
            ],
        ];
        // Merging in the opposite direction yields the opposite library order.
        $expected_b = [
            'http_header' => [
                $expires,
                $content_type,
            ],
        ];
        return [
            [
                $a,
                $b,
                $expected_a,
            ],
            [
                $b,
                $a,
                $expected_b,
            ],
        ];
    }
    
    /**
     * Tests addCacheableDependency().
     *
     * This only tests at a high level, because it reuses existing logic. Detailed
     * tests exist for the existing logic:
     *
     * @see \Drupal\Tests\Core\Cache\CacheTest::testMergeTags()
     * @see \Drupal\Tests\Core\Cache\CacheTest::testMergeMaxAges()
     * @see \Drupal\Tests\Core\Cache\CacheContextsTest
     *
     * @covers ::addCacheableDependency
     * @dataProvider providerTestMerge
     */
    public function testAddCacheableDependency(BubbleableMetadata $a, $b, BubbleableMetadata $expected) : void {
        $cache_contexts_manager = $this->getMockBuilder('Drupal\\Core\\Cache\\Context\\CacheContextsManager')
            ->disableOriginalConstructor()
            ->getMock();
        $cache_contexts_manager->method('assertValidTokens')
            ->willReturn(TRUE);
        $container = new ContainerBuilder();
        $container->set('cache_contexts_manager', $cache_contexts_manager);
        \Drupal::setContainer($container);
        $this->assertEqualsCanonicalizing($expected, $a->addCacheableDependency($b));
    }
    
    /**
     * Provides test data for testMerge().
     *
     * @return array
     */
    public function providerTestAddCacheableDependency() {
        return [
            // Merge in a cacheable metadata.
'merge-cacheable-metadata' => [
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                ])
                    ->setCacheTags([
                    'foo',
                ])
                    ->setCacheMaxAge(20),
                (new CacheableMetadata())->setCacheContexts([
                    'bar',
                ])
                    ->setCacheTags([
                    'bar',
                ])
                    ->setCacheMaxAge(60),
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                    'bar',
                ])
                    ->setCacheTags([
                    'foo',
                    'bar',
                ])
                    ->setCacheMaxAge(20),
            ],
            'merge-bubbleable-metadata' => [
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                ])
                    ->setCacheTags([
                    'foo',
                ])
                    ->setCacheMaxAge(20)
                    ->setAttachments([
                    'foo' => [],
                ]),
                (new BubbleableMetadata())->setCacheContexts([
                    'bar',
                ])
                    ->setCacheTags([
                    'bar',
                ])
                    ->setCacheMaxAge(60)
                    ->setAttachments([
                    'bar' => [],
                ]),
                (new BubbleableMetadata())->setCacheContexts([
                    'foo',
                    'bar',
                ])
                    ->setCacheTags([
                    'foo',
                    'bar',
                ])
                    ->setCacheMaxAge(20)
                    ->setAttachments([
                    'foo' => [],
                    'bar' => [],
                ]),
            ],
            'merge-attachments-metadata' => [
                (new BubbleableMetadata())->setAttachments([
                    'foo' => [],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'bar' => [],
                ]),
                (new BubbleableMetadata())->setAttachments([
                    'foo' => [],
                    'bar' => [],
                ]),
            ],
        ];
    }

}