AEM Unit Test for servlet

[anasustic]

I have to write a Unit Test for a servlet that uses 

@Reference
private transient SearchService searchService;

When I run the doGetTest I get a NullPointerException since this searchService is null:

@Test
void doGetTest() throws IOException {

    MockSlingHttpServletRequest request = context.request();
    MockSlingHttpServletResponse response = context.response();
    underTest.doGet(request, response);

How do I inject this SearchService in my Unit Test?

Thanks in advance.

[Kiran_Vedantam]

Hi @anasustic 

Try to mock the service in your test class as mentioned here : https://taylor.callsen.me/unit-testing-aem-sling-models-and-servlets/

Hope this helps!

Thanks,

Kiran Vedantam.

[milind_bachani]

Hi @anasustic ,

You can use @Mock annotations for creating the mock instance of the service as:

@Mock
SearchService mockSearchService;

Then you can initialize your mocks using initMocks() in setUp() as:

@Before
public void setUp() throws Exception {
     MockitoAnnotations.initMocks(this);
}

And then inside test you can use :

servlet.searchService = mockSearchService;

Hope this helps, thanks!

[anasustic]

Thanks @milind_bachani but I do not unterstand how to do 

servlet.searchService = mockSearchService;

My servlet does not have a method searchService? 

[pankajpandey]

import org.mockito.internal.util.reflection.Whitebox;

Whitebox.setInternalState(underTest, "searchservice", mockedSearchservice);

[anasustic]

Unfortunatelly I do not have the option to import Whitebox in maven.

[milind_bachani]

Hi @anasustic , 

That is initialization of referenced service in test servlet class. 
This is analogous to :

// any referenced service can be initialized by mock using following
servlet.<referenced_service_obj_name> = <mock_service_name>;

Let me know if you still need help, thank you.

[Vijayalakshmi_S]

Hi @anasustic,

Use @Mock (org.mockito.Mock) annotation on the Service in  Test class and to inject this to the servlet under test, use @InjectMocks (org.mockito.InjectMocks) on the servlet instantiation like the below. 

@Mock
private SearchService searchService

@InjectMocks
private SimpleServlet underTest = new SimpleServlet();

Then in the doGetTest() method, before calling underTest.doGet(request, response) -> provide mock implementation for the searchService using when and thenReturn methods. 

Please update this thread in case of any issues. 

[anasustic]

I do not understand what do you mean by

---

mock implementation for the searchService using when and thenReturn methods. 

Please update this thread in case of any issues. 

---

This is what I have 

@ExtendWith(AemContextExtension.class)
class LocationFinderByTitleServiceTest {


    private final AemContext context = ComponentTestContext.createAemContext();

    @Mock
    SearchService searchService;

    @InjectMocks
    private LocationFinderByTitleService underTest = new LocationFinderByTitleService();

    @BeforeEach
    void beforeEach() {
        context.load().json("/component/content/location/content.json", "/content/de");


        Map<String, Object> pm = new HashMap<>();
        pm.put("title", "Shop");
        context.request().setMethod("GET");
        context.request().setParameterMap(pm);
    }


    @Test
    void doGetTest() throws IOException {

        MockSlingHttpServletRequest request = context.request();
        MockSlingHttpServletResponse response = context.response();


        underTest.doGet(request, response);

 I am getting a NullPointerException in the underTest.doGet while the searchService is null.

[Vijayalakshmi_S]

You might be using some method/functionality of SearchService in your actual Servlet class, you need to provide implementation for the same here to the test class. 

Example: If you have searchService.search() and that returns a List object say for example, then we need to write

when(searchService.search()).thenReturn(any(List.class));

Also, in the snippet you have shared, instantiate the AemContext like below 

private AemContext context = new AemContext(ResourceResolverType.RESOURCERESOLVER_MOCK);

or

private AemContext context = new AemContext(ResourceResolverType.JCR_MOCK);

[anasustic]

I did as you suggested and in the beforeEach() added:

context.registerInjectActivateService(new SearchService(),  "prop1", "value1");

The SearchService() has itself two @reference annotations. 

@Reference
private ResourceResolverService resourceResolverService;

@Reference
private GeocodingService geocodingService;

and now I am getting 

org.apache.sling.testing.mock.osgi.ReferenceViolationException: Unable to inject mandatory reference 'geocodingService' for class ....SearchService : no matching services were found.

Can you please suggest how to properly mock these two references?

[Vijayalakshmi_S]

@anasustic 

Register those two Services as well to the AemContext object just before injecting the SearchService.

context.registerService(ResourceResolverService.class, <<instantiation of the service impl/mocked reference>>);
context.registerService(GeocodingService.class, <<instantiation of the service impl/mocked reference>>);
context.registerInjectActivateService(new SearchService(), "prop1", "value1");

[BrianKasingli]

Try this

...
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

private SearchService searchService;

@Test
void doGetTest() throws IOException {
    searchService = mock(SearchService.class);
    when(searchService.get(any()).thenReturn(null);
    MockSlingHttpServletRequest request = context.request();
    MockSlingHttpServletResponse response = context.response();
    underTest.doGet(request, response);

    JsonObject jsonResponse = gson.fromJson(response.getOutputAsString(), JsonObject.class); 
    assertNotNull(jsonResponse.get("searchResults"));
}

[anasustic]

My SearchService class has two @reference annotations

@Reference
private ResourceResolverService resourceResolverService;

@Reference
private GeocodingService geocodingService;

and two public methods with the following signatures:

public List<LocationResult> getResults(@Nonnull GoogleMapsApiConfigurationModel configModel, @Nonnull String pagePath, @Nullable String zipCity)

public void cacheLocations(Resource resource)

 I am not sure how to mock that in 

when(searchService.getResults(???).thenReturn(???) 

[anasustic]

I did as you suggested

@Test
void doGetTest() throws IOException {
    searchService = mock(SearchService.class);
    GoogleMapsApiConfigurationModel model = new GoogleMapsApiConfigurationModel();
    String one = "one";
    String two = "two";
    when(searchService.getResults(model, one, two)).thenReturn(null);
    MockSlingHttpServletRequest request = context.request();
    MockSlingHttpServletResponse response = context.response();
    underTest().doGet(request, response);

 I am getting the following error when I run the test:

at org.apache.sling.testing.mock.osgi.OsgiServiceUtil.injectServiceReference(OsgiServiceUtil.java:435)
at org.apache.sling.testing.mock.osgi.OsgiServiceUtil.injectServices(OsgiServiceUtil.java:418)
at org.apache.sling.testing.mock.osgi.MockOsgi.injectServices(MockOsgi.java:163)
at org.apache.sling.testing.mock.osgi.context.OsgiContextImpl.registerInjectActivateService(OsgiContextImpl.java:155)
at org.apache.sling.testing.mock.osgi.context.OsgiContextImpl.registerInjectActivateService(OsgiContextImpl.java:143)