Set a private field on a class you need to Unit Test

Well, of course, you could make your field with default access, or you can add some boilerplate setter, or you could fancy whipping up a utility using reflection, but spring-test has already thought of that.

Let's say you want to test your DonkeyController:

	import org.springframework.test.util.ReflectionTestUtils;
	public class DonkeyControllerTest {
	DonkeyController donkeyController;
	DonkeyDAO donkeyDAO;
	@Before
	public void setUp() throws Exception {
	donkeyController = new DonkeyController();
	donkeyDAO = new DonkeyDAO();
	ReflectionTestUtils.setField(donkeyController, "donkeyDAO", donkeyDAO);
	}

view raw DonkeyControllerTest hosted with ❤ by GitHub

This is how you can easily set the private field donkeyDAO, without changes in the class under test:

	import org.springframework.test.util.ReflectionTestUtils;
	public class DonkeyControllerTest {
	DonkeyController donkeyController;
	DonkeyDAO donkeyDAO;
	@Before
	public void setUp() throws Exception {
	donkeyController = new DonkeyController();
	donkeyDAO = new DonkeyDAO();
	ReflectionTestUtils.setField(donkeyController, "donkeyDAO", donkeyDAO);
	}

view raw DonkeyControllerTest hosted with ❤ by GitHub

ReflectionTestUtils is in spring-test:

	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-test</artifactId>
	<version>${spring.version}</version>
	</dependency>

view raw spring-test-maven hosted with ❤ by GitHub

Cheers!