expectException(CloneNotSupportedException::class); clone NullValue::instance(); } public function testExceptionOnSerializeAttempt() : void { $this->expectException(SerializeNotSupportedException::class); serialize(NullValue::instance()); } public function testExceptionOnUnserializeAttempt() : void { $this->expectException(UnserializeNotSupportedException::class); unserialize('O:22:"DASPRiD\\Enum\\NullValue":0:{}'); } }