class BackendChainImplementationUnitTest

class BackendChainImplementationUnitTest extends UnitTestCase {

  /**
   * Chain that will be heavily tested.
   *
   * @var \Drupal\Core\Cache\BackendChain
   */
  protected $chain;

  /**
   * First backend in the chain.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface
   */
  protected $firstBackend;

  /**
   * Second backend in the chain.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface
   */
  protected $secondBackend;

  /**
   * Third backend in the chain.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface
   */
  protected $thirdBackend;

  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();

    // Set up three memory backends to be used in the chain.
    $time = new Time();
    $this->firstBackend = new MemoryBackend($time);
    $this->secondBackend = new MemoryBackend($time);
    $this->thirdBackend = new MemoryBackend($time);

    // Set an initial fixed dataset for all testing. The next three data
    // collections will test two edge cases (last backend has the data, and
    // first backend has the data) and will test a normal use case (middle
    // backend has the data). We should have a complete unit test with those.
    // Note that in all cases, when the same key is set on more than one
    // backend, the values are voluntarily different, this ensures in which
    // backend we actually fetched the key when doing get calls.
    // Set a key present on all backends (for delete).
    $this->firstBackend
      ->set('t123', 1231);
    $this->secondBackend
      ->set('t123', 1232);
    $this->thirdBackend
      ->set('t123', 1233);

    // Set a key present on the second and the third (for get), those two will
    // be different, this will ensure from where we get the key.
    $this->secondBackend
      ->set('t23', 232);
    $this->thirdBackend
      ->set('t23', 233);

    // Set a key on only the third, we will ensure propagation using this one.
    $this->thirdBackend
      ->set('t3', 33);

    // Create the chain.
    $this->chain = new BackendChain();
    $this->chain
      ->appendBackend($this->firstBackend)
      ->appendBackend($this->secondBackend)
      ->appendBackend($this->thirdBackend);
  }

  /**
   * Tests the get feature.
   */
  public function testGet() {
    $cached = $this->chain
      ->get('t123');
    $this
      ->assertNotFalse($cached, 'Got key that is on all backends');
    $this
      ->assertSame(1231, $cached->data, 'Got the key from the backend 1');
    $cached = $this->chain
      ->get('t23');
    $this
      ->assertNotFalse($cached, 'Got key that is on backends 2 and 3');
    $this
      ->assertSame(232, $cached->data, 'Got the key from the backend 2');
    $cached = $this->chain
      ->get('t3');
    $this
      ->assertNotFalse($cached, 'Got key that is on the backend 3');
    $this
      ->assertSame(33, $cached->data, 'Got the key from the backend 3');
  }

  /**
   * Tests the get multiple feature.
   */
  public function testGetMultiple() {
    $cids = [
      't123',
      't23',
      't3',
      't4',
    ];
    $ret = $this->chain
      ->getMultiple($cids);
    $this
      ->assertSame($ret['t123']->data, 1231, 'Got key 123 and value is from the first backend');
    $this
      ->assertSame($ret['t23']->data, 232, 'Got key 23 and value is from the second backend');
    $this
      ->assertSame($ret['t3']->data, 33, 'Got key 3 and value is from the third backend');
    $this
      ->assertArrayNotHasKey('t4', $ret);
    $this
      ->assertNotContains('t123', $cids, "Existing key 123 has been removed from &\$cids");
    $this
      ->assertNotContains('t23', $cids, "Existing key 23 has been removed from &\$cids");
    $this
      ->assertNotContains('t3', $cids, "Existing key 3 has been removed from &\$cids");
    $this
      ->assertContains('t4', $cids, "Non existing key 4 is still in &\$cids");
  }

  /**
   * Tests that set will propagate.
   */
  public function testSet() {
    $this->chain
      ->set('test', 123);
    $cached = $this->firstBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key is in the first backend');
    $this
      ->assertSame(123, $cached->data, 'Test key has the right value');
    $cached = $this->secondBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key is in the second backend');
    $this
      ->assertSame(123, $cached->data, 'Test key has the right value');
    $cached = $this->thirdBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key is in the third backend');
    $this
      ->assertSame(123, $cached->data, 'Test key has the right value');
  }

  /**
   * Tests that delete will propagate.
   */
  public function testDelete() {
    $this->chain
      ->set('test', 5);
    $cached = $this->firstBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key has been added to the first backend');
    $cached = $this->secondBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key has been added to the first backend');
    $cached = $this->thirdBackend
      ->get('test');
    $this
      ->assertNotFalse($cached, 'Test key has been added to the first backend');
    $this->chain
      ->delete('test');
    $cached = $this->firstBackend
      ->get('test');
    $this
      ->assertFalse($cached, 'Test key is removed from the first backend');
    $cached = $this->secondBackend
      ->get('test');
    $this
      ->assertFalse($cached, 'Test key is removed from the second backend');
    $cached = $this->thirdBackend
      ->get('test');
    $this
      ->assertFalse($cached, 'Test key is removed from the third backend');
  }

  /**
   * Ensure get values propagation to previous backends.
   */
  public function testGetHasPropagated() {
    $this->chain
      ->get('t23');
    $cached = $this->firstBackend
      ->get('t23');
    $this
      ->assertNotFalse($cached, 'Test 2 has been propagated to the first backend');
    $this->chain
      ->get('t3');
    $cached = $this->firstBackend
      ->get('t3');
    $this
      ->assertNotFalse($cached, 'Test 3 has been propagated to the first backend');
    $cached = $this->secondBackend
      ->get('t3');
    $this
      ->assertNotFalse($cached, 'Test 3 has been propagated to the second backend');
  }

  /**
   * Ensure get multiple values propagation to previous backends.
   */
  public function testGetMultipleHasPropagated() {
    $cids = [
      't3',
      't23',
    ];
    $this->chain
      ->getMultiple($cids);
    $cached = $this->firstBackend
      ->get('t3');
    $this
      ->assertNotFalse($cached, 'Test 3 has been propagated to the first backend');
    $this
      ->assertSame(33, $cached->data, 'And value has been kept');
    $cached = $this->secondBackend
      ->get('t3');
    $this
      ->assertNotFalse($cached, 'Test 3 has been propagated to the second backend');
    $this
      ->assertSame(33, $cached->data, 'And value has been kept');
    $cached = $this->firstBackend
      ->get('t23');
    $this
      ->assertNotFalse($cached, 'Test 2 has been propagated to the first backend');
    $this
      ->assertSame(232, $cached->data, 'And value has been kept');
  }

  /**
   * Tests that the delete all operation is propagated to all chained backends.
   */
  public function testDeleteAllPropagation() {

    // Set both expiring and permanent keys.
    $this->chain
      ->set('test1', 1, Cache::PERMANENT);
    $this->chain
      ->set('test2', 3, time() + 1000);
    $this->chain
      ->deleteAll();
    $this
      ->assertFalse($this->firstBackend
      ->get('test1'), 'First key has been deleted in first backend.');
    $this
      ->assertFalse($this->firstBackend
      ->get('test2'), 'Second key has been deleted in first backend.');
    $this
      ->assertFalse($this->secondBackend
      ->get('test1'), 'First key has been deleted in second backend.');
    $this
      ->assertFalse($this->secondBackend
      ->get('test2'), 'Second key has been deleted in second backend.');
    $this
      ->assertFalse($this->thirdBackend
      ->get('test1'), 'First key has been deleted in third backend.');
    $this
      ->assertFalse($this->thirdBackend
      ->get('test2'), 'Second key has been deleted in third backend.');
  }

  /**
   * Tests that the delete tags operation is propagated to all chained backends.
   */
  public function testDeleteTagsPropagation() {

    // Create two cache entries with the same tag and tag value.
    $this->chain
      ->set('test_cid_clear1', 'foo', Cache::PERMANENT, [
      'test_tag:2',
    ]);
    $this->chain
      ->set('test_cid_clear2', 'foo', Cache::PERMANENT, [
      'test_tag:2',
    ]);
    $this
      ->assertNotFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2'), 'Two cache items were created in all backends.');

    // Invalidate test_tag of value 1. This should invalidate both entries.
    $this->chain
      ->invalidateTags([
      'test_tag:2',
    ]);
    $this
      ->assertFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2'), 'Two caches removed from all backends after clearing a cache tag.');

    // Create two cache entries with the same tag and an array tag value.
    $this->chain
      ->set('test_cid_clear1', 'foo', Cache::PERMANENT, [
      'test_tag:1',
    ]);
    $this->chain
      ->set('test_cid_clear2', 'foo', Cache::PERMANENT, [
      'test_tag:1',
    ]);
    $this
      ->assertNotFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2'), 'Two cache items were created in all backends.');

    // Invalidate test_tag of value 1. This should invalidate both entries.
    $this->chain
      ->invalidateTags([
      'test_tag:1',
    ]);
    $this
      ->assertFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2'), 'Two caches removed from all backends after clearing a cache tag.');

    // Create three cache entries with a mix of tags and tag values.
    $this->chain
      ->set('test_cid_clear1', 'foo', Cache::PERMANENT, [
      'test_tag:1',
    ]);
    $this->chain
      ->set('test_cid_clear2', 'foo', Cache::PERMANENT, [
      'test_tag:2',
    ]);
    $this->chain
      ->set('test_cid_clear3', 'foo', Cache::PERMANENT, [
      'test_tag_foo:3',
    ]);
    $this
      ->assertNotFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->firstBackend
      ->get('test_cid_clear3') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear3') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear3'), 'Three cached items were created in all backends.');
    $this->chain
      ->invalidateTags([
      'test_tag_foo:3',
    ]);
    $this
      ->assertNotFalse($this->firstBackend
      ->get('test_cid_clear1') && $this->firstBackend
      ->get('test_cid_clear2') && $this->secondBackend
      ->get('test_cid_clear1') && $this->secondBackend
      ->get('test_cid_clear2') && $this->thirdBackend
      ->get('test_cid_clear1') && $this->thirdBackend
      ->get('test_cid_clear2'), 'Cached items not matching the tag were not cleared from any of the backends.');
    $this
      ->assertFalse($this->firstBackend
      ->get('test_cid_clear3') && $this->secondBackend
      ->get('test_cid_clear3') && $this->thirdBackend
      ->get('test_cid_clear3'), 'Cached item matching the tag was removed from all backends.');
  }

  /**
   * Tests that removing bin propagates to all backends.
   */
  public function testRemoveBin() {
    $chain = new BackendChain();
    for ($i = 0; $i < 3; $i++) {
      $backend = $this
        ->createMock('Drupal\\Core\\Cache\\CacheBackendInterface');
      $backend
        ->expects($this
        ->once())
        ->method('removeBin');
      $chain
        ->appendBackend($backend);
    }
    $chain
      ->removeBin();
  }

}