class CacheTestBase

abstract class CacheTestBase extends BrowserTestBase {
    protected $defaultBin = 'render';
    protected $defaultCid = 'test_temporary';
    protected $defaultValue = 'CacheTest';
    
    /**
     * Checks whether or not a cache entry exists.
     *
     * @param $cid
     *   The cache id.
     * @param $var
     *   The variable the cache should contain.
     * @param $bin
     *   The bin the cache item was stored in.
     *
     * @return bool
     *   TRUE on pass, FALSE on fail.
     */
    protected function checkCacheExists($cid, $var, $bin = NULL) {
        if ($bin == NULL) {
            $bin = $this->defaultBin;
        }
        $cached = \Drupal::cache($bin)->get($cid);
        return isset($cached->data) && $cached->data == $var;
    }
    
    /**
     * Asserts that a cache entry exists.
     *
     * @param $message
     *   Message to display.
     * @param $var
     *   The variable the cache should contain.
     * @param $cid
     *   The cache id.
     * @param $bin
     *   The bin the cache item was stored in.
     */
    protected function assertCacheExists($message, $var = NULL, $cid = NULL, $bin = NULL) {
        if ($bin == NULL) {
            $bin = $this->defaultBin;
        }
        if ($cid == NULL) {
            $cid = $this->defaultCid;
        }
        if ($var == NULL) {
            $var = $this->defaultValue;
        }
        $this->assertTrue($this->checkCacheExists($cid, $var, $bin), $message);
    }
    
    /**
     * Asserts that a cache entry has been removed.
     *
     * @param $message
     *   Message to display.
     * @param $cid
     *   The cache id.
     * @param $bin
     *   The bin the cache item was stored in.
     */
    public function assertCacheRemoved($message, $cid = NULL, $bin = NULL) {
        if ($bin == NULL) {
            $bin = $this->defaultBin;
        }
        if ($cid == NULL) {
            $cid = $this->defaultCid;
        }
        $cached = \Drupal::cache($bin)->get($cid);
        $this->assertFalse($cached, $message);
    }

}