public function testKey()
{
$key1 = Memory::key();
$this->assertNotEmpty($key1);
$key2 = Memory::key();
$this->assertNotEqual($key1, $key2);
$pattern = '/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/';
$this->assertPattern($pattern, Memory::key());
}