Cachearium\CacheAbstract::delete PHP Method

    public abstract function delete(CacheKey $k);

 public function increment(CacheAbstract $cache)
 {
     $key = new CacheKey('increment', 'it');
     $cache->delete($key);
     $this->assertEquals(5, $cache->increment(1, $key, 5));
     $this->assertEquals(6, $cache->increment(1, $key, 5));
 }