Cache::clear PHP Method

    function clear($key)
    {
        if (!$this->dsn) {
            return;
        }
        $ndx = $this->prefix . '.' . $key;
        $parts = explode('=', $this->dsn, 2);
        switch ($parts[0]) {
            case 'apc':
            case 'apcu':
                return apc_delete($ndx);
            case 'redis':
                return $this->ref->del($ndx);
            case 'memcache':
                return memcache_delete($this->ref, $ndx);
            case 'wincache':
                return wincache_ucache_delete($ndx);
            case 'xcache':
                return xcache_unset($ndx);
            case 'folder':
                return @unlink($parts[1] . $ndx);
        }
        return FALSE;
    }

 /**
  * @covers Phossa\Config\Env\Environment::save()
  * @covers Phossa\Config\Env\Environment::get()
  * @covers Phossa\Config\Env\Environment::clear()
  */
 public function testSave()
 {
     $data = ['db' => ['dsn' => 'bingo']];
     $this->object->save($data);
     $this->assertEquals($data, $this->object->get());
     $this->object->clear();
     $this->assertFalse($this->object->get());
 }