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.
        $this->firstBackend = new MemoryBackend();
        $this->secondBackend = new MemoryBackend();
        $this->thirdBackend = new MemoryBackend();
        // 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();
    }

}