public function testBasicApi()
 {
     // test de-coupled instance
     $cache = new \ElggVolatileMetadataCache();
     $cache->setIgnoreAccess(false);
     $guid = 1;
     $this->assertFalse($cache->isKnown($guid, $this->name));
     $cache->markEmpty($guid, $this->name);
     $this->assertTrue($cache->isKnown($guid, $this->name));
     $this->assertNull($cache->load($guid, $this->name));
     $cache->markUnknown($guid, $this->name);
     $this->assertFalse($cache->isKnown($guid, $this->name));
     $cache->save($guid, $this->name, $this->value);
     $this->assertIdentical($cache->load($guid, $this->name), $this->value);
     $cache->save($guid, $this->name, 1, true);
     $this->assertIdentical($cache->load($guid, $this->name), array($this->value, 1));
     $cache->clear($guid);
     $this->assertFalse($cache->isKnown($guid, $this->name));
 }