Develop Reference

CompletableFeature gives NullPointerException on last asyncTask call

I have an issue running Controller Tests with CompletableFeature,
I create a StockController!
#Component
public class StockController implements StockResource {
private UseCaseExecutor useCaseExecutor;
private GetAllStocksUseCase getAllStocksUseCase;
#Autowired
public StockController(UseCaseExecutor useCaseExecutor,
GetAllStocksUseCase getAllStocksUseCase) {
this.useCaseExecutor = useCaseExecutor;
this.getAllStocksUseCase = getAllStocksUseCase;
}
#Override
public CompletableFuture<List<StockResponse>> getAllStocks(
#RequestParam(value="materialNumber", required=false) String materialNumber,
#RequestParam(value="storageLocation", required=false) String storageLocation,
#RequestParam(value="plant", required=false) String plant) {
return useCaseExecutor.execute(
getAllStocksUseCase,
GetAllStocksInputMapper.map(
materialNumber,
storageLocation,
plant
),
(outputValues) -> StockResponse.from(outputValues.getStockList()));
}
And create a StockControllerTest
#RunWith(SpringRunner.class)
#WebMvcTest(value = StockController.class, secure = false)
public class StockControllerTest {
#MockBean
private GetAllStocksUseCase getAllStocksUseCase;
#SpyBean
private UseCaseExecutorImpl useCaseExecutor;
#Autowired
private MockMvc mockMvc;
#Configuration
#ComponentScan(basePackages = {"com.example.presenter.rest.api.stock"})
static class Config {
}
#Test
public void deliveryOrderReturnsOk() throws Exception {
Stock stock = TestEntityGenerator.randomStock();
GetAllStocksUseCase.InputValues input = GetAllStocksInputMapper.map(
stock.getMaterialNumber(),
stock.getStorageLocation(),
stock.getPlant());
GetAllStocksUseCase.OutputValues output = new GetAllStocksUseCase.OutputValues(Collections.singletonList(stock));
doReturn(output)
.when(getAllStocksUseCase)
.execute(input);
final String request =
"/api/stocks?materialNumber=" +
stock.getMaterialNumber() + "&plant=" + stock.getPlant() + "&storageLocation=" + stock.getStorageLocation();
RequestBuilder payload = asyncGetRequest(request);
mockMvc.perform(payload)
.andExpect(status().isOk())
.andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
.andExpect(jsonPath("$.[0].materialNumber", is(stock.getMaterialNumber())))
.andExpect(jsonPath("$.[0].plant", is(stock.getPlant())))
.andExpect(jsonPath("$.[0].storageLocation", is(stock.getStorageLocation())))
.andExpect(jsonPath("$.[0].availableQuantity", is(stock.getAvailableQuantity())))
.andExpect(jsonPath("$.[0].quantity", is(stock.getQuantity())));
}
protected RequestBuilder asyncGetRequest(String url) throws Exception {
return asyncDispatch(mockMvc.perform(get(url))
.andExpect(request().asyncStarted())
.andReturn());
}
}
And have a UseCaseExecutor to run a useCase with some input to generate some output.
GetAllStocksUseCase
#Service
public class GetAllStocksUseCase extends UseCase<GetAllStocksUseCase.InputValues, GetAllStocksUseCase.OutputValues> {
private StockDAO stockDAO;
#Autowired
public GetAllStocksUseCase(StockDAO stockDAO) {
this.stockDAO = stockDAO;
}
#Override
public OutputValues execute(InputValues input) {
return new OutputValues(stockDAO.getAll(input.getStock()));
}
public static class InputValues implements UseCase.InputValues {
private Stock stock;
public InputValues(Stock stock) {
this.stock = stock;
}
public Stock getStock() {
return stock;
}
}
public static class OutputValues implements UseCase.OutputValues {
List<Stock> stockList;
public OutputValues(List<Stock> stockList) {
this.stockList = stockList;
}
public List<Stock> getStockList() {
return stockList;
}
}
}
UseCaseExecutor
#Service
public class UseCaseExecutorImpl implements UseCaseExecutor {
#Override
public <RX, I extends UseCase.InputValues, O extends UseCase.OutputValues> CompletableFuture<RX> execute(
UseCase<I, O> useCase, I input, Function<O, RX> outputMapper) {
return CompletableFuture
.supplyAsync(() -> input)
.thenApplyAsync(useCase::execute)
.thenApplyAsync(outputMapper);
}
}
When I run the test it gives a NullPointException on OutputValues
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1013)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:166)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:182)
at com.example.presenter.rest.api.stock.StockControllerTest.deliveryOrderReturnsOk(StockControllerTest.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.NullPointerException
at com.example.presenter.rest.api.stock.StockController.lambda$getAllStocks$0(StockController.java:37)
at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Can anyone help me with this problem? It seems that it does not run the execute of useCase before the outputMapper so the OutputValues are null

Spring MockMvc Test : NullPointerException for mvc.perform()

I am new to unit test in spring Boot. I am trying to run a simple test of the controller.
But i'am getting a NullPointerException.
here is my code :
The controller class:
#RequestMapping("/trainings")
public class TrainingController {
#Autowired
TrainingService ts;
#PostMapping()
public JsonResponse<AllTrainings> getTrainings(){
JsonResponse<AllTrainings> json = new JsonResponse<AllTrainings>();
json.setStatus(JsonResponse.Status.OK);
json.setData(new AllTrainings(ts.getTrainings()));
return json;
}}
The TrainingTest :
#RunWith(SpringRunner.class)
public abstract class TrainingTest {
protected MockMvc mvc;
protected ObjectMapper mapper = new ObjectMapper();
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public abstract void testGetTrainings() throws Exception;
#Test
public abstract void testGetTrainingById() throws Exception;
protected String toJson(Object object) throws JsonProcessingException {
return mapper.writeValueAsString(object);
}
}
The TrainingControllerTest :
public class TrainingControllerTest extends TrainingTest{
#InjectMocks protected TrainingController controller;
#MockBean
TrainingRepository trainingRepo;
#Before
public void setup(){
super.setup();
mvc = MockMvcBuilders.standaloneSetup(this.controller).build();
}
#Override
public void testGetTrainings() throws Exception {
Training ang = new Training("TR0004");
Mockito
.when(this.trainingRepo.findAll())
.thenReturn(Arrays.asList(ang));
mvc.perform(MockMvcRequestBuilders.get("/trainings")
.contentType(MediaType.APPLICATION_JSON_VALUE))
.andDo(MockMvcResultHandlers.print())
.andExpect(MockMvcResultMatchers.status().isOk());
}
And here the error i'am getting:
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1013)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:166)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:182)
at fr.ter.forco.training.TrainingControllerTest.testGetTrainings(TrainingControllerTest.java:41)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: java.lang.NullPointerException
at fr.ter.forco.controllers.TrainingController.getTrainings(TrainingController.java:38)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
... 41 more
The exception appears in the mvc.perform!
I really don't know why i'am getting this error.
Thank you.

I'm not sure why you're getting this error but maybe if you add the #AutoConfigureMockMvc above your test class it could work? I always add this annotation when making use of MockMvc.

Testing case where null should be returned using RestController with Mockito Fails

I want to test for a NullPointerException case that should be thrown by the controller that I am testing, but I always get NullPointerException error. I am trying to test the case where a user with a certain id is not found in the db. Is my way of doing that a valid way? If not, then how should I test that case? I haven't found any valuable info about this certain test case.
My Controller Test:
#RunWith(SpringJUnit4ClassRunner.class)
#WebMvcTest(value = UserController.class)
public class UserControllerTest
{
#Autowired
private MockMvc mockMvc;
#MockBean
private UserRepository userRepository;
#Test
public void testGetUserById_Status200_EmptyJsonPath() throws Exception
{
when(userRepository.findById(999)).thenReturn(null);
mockMvc.perform(get("/user/{user_id}", 999))
.andExpect(status().isNotFound());
verify(userRepository, times(1)).findById(999);
verifyNoMoreInteractions(userRepository);
}
My Controller:
#RestController
public class UserController
{
#Autowired
private UserRepository userRepository;
#RequestMapping(value = "/user/{user_id}")
public User getUser(#PathVariable int user_id) throws Exception
{
return userRepository.findById(user_id).orElse(null);
}
}
Error I get:
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1013)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:166)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:182)
at spring.controller.UserControllerTest.testGetUserById_Status200_EmptyJsonPath(UserControllerTest.java:111)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:365)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$4.run(ParentRunner.java:330)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:78)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:328)
at org.junit.runners.ParentRunner.access$100(ParentRunner.java:65)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:292)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:305)
at org.junit.runners.ParentRunner.run(ParentRunner.java:412)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.NullPointerException
at spring.controller.UserController.getUser(UserController.java:35)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
... 49 more

You can use
assertThatNullPointerException().isThrownBy(() -> userRepository.findById(999));
make sure you import following to use this method
import static org.assertj.core.api.Assertions.assertThatNullPointerException;

JUnit assertion null - using stubs and mocks

Here is my test method:
#Test
public void shouldReturnUser_whenPassedUser() {
// given
when(userStub.getUsername()).thenReturn(defaultName);
when(userStub.getPassword()).thenReturn(defaultPassword);
when(userStub.getEmail()).thenReturn(defaultEmail);
// when
User savedUser = userServiceBean.saveUser(userStub);
// then
assertNotNull(savedUser);
verify(userRepository, times(1)).save(any(User.class));
}
Here is my setup:
#Spy
#InjectMocks
private UserServiceBean userServiceBean;
#Mock
private UserRepository userRepository;
#Mock
private Principal principal;
#Mock
private PasswordEncoder passwordEncoder;
#Mock
private User userStub;
private String defaultName = "user";
private String defaultPassword = "password";
private String defaultEmail = "example#example.com";
#Before
public void init() {
MockitoAnnotations.initMocks(this);
}
And here is my userService.saveUser method:
public User saveUser(User user) {
User newUser = new User(user.getUsername(), user.getEmail(), passwordEncoder.encode(user.getPassword()));
return userRepository.save(newUser);
}
And my test results:
java.lang.AssertionError
at org.junit.Assert.fail(Assert.java:86)
at org.junit.Assert.assertTrue(Assert.java:41)
at org.junit.Assert.assertNotNull(Assert.java:712)
at org.junit.Assert.assertNotNull(Assert.java:722)
at com.doublemc.services.UserServiceBeanTest.shouldReturnUser_whenPassedUser(UserServiceBeanTest.java:93)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Why does my method return null? I'm using a stubUser and I tell him exactly what to return to each getter (as I'm doing in my saveUser method) and it still returns null? How should I change that test to work?

You forgot to define the mock behaviour for the userRepository mock. So Mockito uses the default return value null for save.
Define the behaviour like this:
when(userRepository.save(any(User.class))).thenReturn(new User("saved name", "saved email", "saved password"));

Spring Controller Testing using Mockito , Null Pointer Exception

I am trying to test a Spring Controller using Mockito. I have mocked the object also used when() as per this question , but I am still facing the null pointer exception. Please suggest a way to solve this exception.
Github repository of this project
The particular line null pointer linked to is
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
I have mocked simpleCategoryDAO and used when() to return a list for getAllCategories().
Test Method:
#RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
#InjectMocks
private CategoryController categoryController;
#Mock
private SimpleCategoryDAO simpleCategoryDAO;
#Before
public void setup() {
categoryController = new CategoryController();
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
#Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1,"Funny"),
new Category(2,"JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}
Code of controller
#Controller
public class CategoryController {
#Autowired
SimpleCategoryDAO simpleCategoryDAO;
#Autowired
SimpleGifDAO simpleGifDAO;
#RequestMapping("/categories")
public String getAllCategories(ModelMap modelMap) {
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
return "categories";
}
#RequestMapping("/category/{categoryID}")
public String getGifsByCategoryID(#PathVariable int categoryID,ModelMap modelMap){
modelMap.put("gifs", simpleGifDAO.findGifsByCategoryID(categoryID));
modelMap.put("category",simpleCategoryDAO.getCategoryByID(categoryID));
return "category";
}
}
Exception:
java.lang.NullPointerException: null
at com.teja.controller.CategoryController.getAllCategories(CategoryController.java:23) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) ~[spring-web-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) ~[spring-web-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [tomcat-embed-core-8.0.23.jar:8.0.23]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:65) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.0.23.jar:8.0.23]
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:144) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at CategoryControllerTest.categories_ShouldRenderCategoriesView(CategoryControllerTest.java:46) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) [junit-4.12.jar:4.12]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37) [mockito-core-1.10.19.jar:na]
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62) [mockito-core-1.10.19.jar:na]
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]

The problem is on your test class Before method you are instantiating new controller
#Before
public void setup() {
categoryController = new CategoryController();
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
Here is how I do test for Controller
Controller Class :
#Controller
public class CategoryController {
private SimpleCategoryDAO simpleCategoryDAO;
private SimpleGifDAO simpleGifDAO;
#Autowired
public void setSimpleGifDAO(SimpleGifDAO simpleGifDAO) {
this.simpleGifDAO = simpleGifDAO;
}
#Autowired
public void setSimpleCategoryDAO(SimpleCategoryDAO simpleCategoryDAO) {
this.simpleCategoryDAO = simpleCategoryDAO;
}
#RequestMapping("/categories")
public String getAllCategories(ModelMap modelMap) {
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
return "categories";
}
#RequestMapping("/category/{categoryID}")
public String getGifsByCategoryID(#PathVariable int categoryID, ModelMap modelMap) {
modelMap.put("gifs", simpleGifDAO.findGifsByCategoryID(categoryID));
modelMap.put("category", simpleCategoryDAO.getCategoryByID(categoryID));
return "category";
}
}
Notice I'm using setter injection here not field injection. You can also use constructor injection ( preferred way for me).
In you test class
#RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
#Mock
private SimpleCategoryDAO simpleCategoryDAO;
#Before
public void setup() {
final CategoryController categoryController = new CategoryController();
//notice here I'm setting the mocked dao here
// if you didn't use #RunWith(MockitoJUnitRunner.class)
// you can do: simpleCategoryDAO = Mockito.mock(SimpleCategoryDAO.class);
categoryController.setSimpleCategoryDAO(simpleCategoryDAO);
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
#Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1, "Funny"),
new Category(2, "JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}
Take a look at Before method on test. I'm setting the mocked DAO on the new instance of controller that I've created and then I'm creating the MockMvc using same instance of controller.

I had some issues with the provided solution so I thought I'd share how I solved it. My issue was that when the controller called a method on the DAO it was throwing NullPointerException, because I didn't want to use setter injection to provide the mocked DAO to the controller (I refused to create a setter method in the DAO just to be able to test everything).
Basically for the OP it would require:
NOT instantiating the controller in the setup() method (like Aman pointed out)
Declaring the DAO with the #Mock annotation before the controller declaration.
Like so:
#RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
#Mock
private SimpleCategoryDAO simpleCategoryDAO;
#InjectMocks
private CategoryController categoryController;
#Before
public void setup() {
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
#Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1,"Funny"),
new Category(2,"JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}