JUnit test cases using mockito for Rest API

Question

I am new to Mockito framework , I have a rest APi that connects my application to jasper server and do report related operations.I want to write junit test cases for rest API using mockito framework.

here i have class called Repositoryclient , Its constructor have instance of JasperServerInfo DAO class.

public class RepositoryClient {

    public RepositoryClient(ServerInfo serverInfo) {
        this.info = serverInfo;

        try {

            Session = Client.authenticate(info.username.trim(), info.password.trim());
        }
        catch (Exception e) {

        }
    }
     public void Templates() {  //this method brings list of present report in jasper server repository     
        try {
            OperationResult<...> result = ....;               


        } catch (Exception e) {
            INodeProcessor.logger.warn(e.toString());
            throw Error.REPORT_TEMPLATE_LIST_ERROR.with();
        }
}

So how to write JUnit test cases using mockito for this class please guide me through. Thank you in advance.

Answer 1

@RunWith(SpringJUnit4ClassRunner.class)
public class UserControllerTest {

    @InjectMocks
    private UserController userController;

    @Mock
    private RequestAttributes attrubutes;

    @Mock
    private UserService userService;

    private MockMvc mockMvc;

    @Before
    public void setup() {
        RequestContextHolder.setRequestAttributes(attrubutes);
        this.mockMvc = MockMvcBuilders.standaloneSetup(userController).build();
    }

    @Test
    public void getUserinfoDetails() {
        String userId = "123";
        String userName = "Test145";
        List<UserDto> userDtoList = new ArrayList<>();
        Mockito.when(userService.getAllUserInfo()).thenReturn(userDtoList);
        Assert.assertNotNull(userController.getUserinfo());
        Assert.assertNotNull(userDtoList);
        Assert.assertNotNull(userId);
        Assert.assertNotNull(userName);

    }
    @Test
    public void getUserByIdDetails() {
        String userId = "123";
        UserDto userDto = new UserDto();
        Mockito.when(userService.getUserByUserId(userId)).thenReturn(userDto);
        Assert.assertNotNull(userController.getUserById(userId));
        Assert.assertNotNull(userDto);
        Assert.assertNotNull(userId);
    }
}

===========================================================================

for reference use below link:(step by step explanation)

https://www.youtube.com/watch?v=yGLOexeJfKA&t=17s

Answer 2

        getting started example that i have :
        import static org.mockito.Mockito.mock;
        import static org.mockito.Mockito.when;

        @Test(priority = 31, groups = "success")
            public void mockExample() {
                Category category1 = mock(Category.class);
                when(category1.getName()).thenReturn("Yess!!!");
                System.out.println(category1.getName());
            }

will print:"Yess!!!"

you can read from here :

http://examples.javacodegeeks.com/core-java/mockito/mockito-hello-world-example/

Answer 3

Well, the code could be improved to make it actually testable...

At the moment, there is no really good way to write unit tests for your code, since the constructor creates a JasperserverRestClient without any chance to change it. The least you can do is add another constructor (may be package access) to allow another JasperserverRestClient to be used. (Alternatively you could think about using a Factory pattern. but this might be to complicated.)

Then you could mock that...

JasperserverRestClient jasperServerClient = Mockito.mock( JasperserverRestClient.class );
RestClientSession session = Mockito.mock( RestClientSession.class );

Mockito.when( jasperServerClient.authenticate( "x", "y")).thenReturn( session );

RepositoryClient repositoryClient = new RepositoryClient(jasperServerClient);

This would at least allow you to test, that authenticate is called with the correct parameters via Mockito.verify.

Also it would allow you to test that the listTemplates method calls the session with the correct parameters (of course you'll need to so some more mocking there).

An additional constructor, assuming your tests are in the same package, would look like this:

RepositoryClient(JasperserverRestClient httpRestClient, JasperServerInfo serverInfo) {
    this.info = serverInfo;
    this.httpRestClient = httpRestClient;

    try {
        restClientSession = httpRestClient.authenticate(info.username.trim(), info.password.trim());
    }
    catch (Exception e) {
        INodeProcessor.logger.warn(e.toString());
        throw Error.REPOSITORY_CLIENT_ERROR.with();
    }
}

This way you can inject a mocked instance of your JasperserverRestClient into your object.

A test of your listTemplates method would (addtionally) look like this...

X resourcesService = Mockito.mock( X.class ); // No clue what the resourcesService() method is supposed to return, fill that in here
Mockito.when ( restClientSession.resourcesService() ).thenReturn ( resourcesService );

...This will allow the part restClientSession.resourcesService() to work. Next...

Y resources = Mockito.mock( Y.class ); // Same thing here, don't know what resources() should return, insert that class here
Mockito.when( resourcesService.resources()).thenReturn ( resources );

This will allow the resources() call to work.

Next we do some trickery:

Mockito.when( resources.parameter( Mockito.anyString(), Mockito.anyString()).thenReturn(resources); // assuming that ResourceSearchParameter constant is a String

This will allow the parameter() calls to work by returning the same resources() object.

And so on... You will need to when(...).thenReturn(...) the search method to return a OperationResult<ClientResourceListWrapper>, etc. but that's the same stuff as above.

And in the end, we could verify that the methods were called with the right parameters...

Mockito.verify( resources, Mockito.times(1)).parameter(ResourceSearchParameter.FOLDER_URI, info.reportDirectory);

Mockito.verify( resources, Mockito.times(1)).parameter(ResourceSearchParameter.RECURSIVE, "false"

Mockito.verify( resources, Mockito.times(1)).search();