['username' => 'someone', 'email' => 'someone@example.com']]); $mapper = new UserMapper($storage); $user = $mapper->findById(1); $this->assertInstanceOf(User::class, $user); } public function testWillNotMapInvalidData() { $this->expectException(InvalidArgumentException::class); $storage = new StorageAdapter([]); $mapper = new UserMapper($storage); $mapper->findById(1); } }