Mock static method of a class in java in junit test cases.

Hi Guys,

In this blog, I am going to explain you about how to mock a static method of a class which we are using in the test class for which we are writing the test case.

For this purpose, I am using PowerMockito framework. PowerMockito is a PowerMock’s extension API which supports Mockito. PowerMockito provides capabilities to overcome the problems of Mockito, such as the lack of ability to mock static, final or private methods.

Below is a simple example to use PowerMockito in junit test case:

@RunWith(PowerMockRunner.class)
@PrepareForTest(fullyQualifiedNames = "org.springframework.security.core.context.SecurityContextHolder")
public class AttendanceBreakWebServiceImplTest {

	private AttendanceBreakWebServiceImpl attendanceBreakWebServiceImpl;
	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@AfterClass
	public static void tearDownAfterClass() throws Exception {
	}
	@Before
	public void setUp() throws Exception {
		attendanceBreakWebServiceImpl = new AttendanceBreakWebServiceImpl();
		mockStatic(SecurityContextHolder.class);
		when(SecurityContextHolder.getContext()).thenReturn(securityContext);
	}
	@After
	public void tearDown() throws Exception {
	}
	@Test
	public void testGetAttendanceBreaks() {
		List attendanceBreakWSList = attendanceBreakWebServiceImpl.getAttendanceBreaks("09/27/2017",
				"10/27/2017");
		assertTrue("attendanceBreakWSList is not empty", attendanceBreakWSList.isEmpty());
	}
}

In the above code we just have to run with "PowerMockRunner.class" and add "@PrepareForTest" for the class name for which you want to mock static method.

Without these two above annotations the test will fail. Please note that you can mock static methods in a class even though the class is final. The method can also be final.

Hope it help in writing junit test cases.