public function testTitle() { $title1 = new Title('test'); $title2 = new Title('new test'); $message = new Message(new Body('test')); $message1 = $message->withTitle($title1); $this->assertSame($title1, $message1->getTitle()); $message2 = $message->withTitle($title2); $this->assertSame($title2, $message2->getTitle()); }