Develop Reference

JUnit AssertionError: Expecting code to raise a throwable

I am trying to write a test for a method that throws custom exception. It fails with Assertion error. What could be done to properly catch the exception and pass the test?
Service method:
#Service
public class CustomServiceImpl implements CustomService {
#Autowired
UserUtil userUtil;
public ResultDTO getResultDto (String type, Long id) throws CustomException {
User user = userUtil.getCurrentUser();
if (user == null) {
throw new CustomException("User does not exist");
}
}
}
Test method:
#MockBean
CustomServiceImpl customServiceImpl ;
#Test
public void test01_getResultDto() {
UserUtil userUtil = Mockito.mock(UserUtil.class);
Mockito.when(userUtil.getCurrentUser()).thenReturn(null);
Assertions.assertThatThrownBy(() -> customServiceImpl.getResultDto (Mockito.anyString(), Mockito.anyLong()))
.isInstanceOf(CustomException .class)
.hasMessage("User does not exist");
}
This test fails with the following error:
java.lang.AssertionError: Expecting code to raise a throwable.
at com.ps.service.CustomServiceImplTest.test01_getResultDto(CustomServiceImplTest.java:62)
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.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:252)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
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:191)
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)
--------------------------- EDIT ------------------------
Changed the code Test to include the following
#Mock
UserUtil userUtil;
#InjectMocks
CustomServiceImpl cutomServiceImpl;
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
}
#Test
public void test01_getResultDto() {
when(userUtil.getCurrentUser()).thenReturn(null);
assertThatThrownBy(() -> customServiceImpl.getResultDto ("type", 1L))
.isInstanceOf(CustomException .class)
.hasMessage("User does not exist");
}
Seems to be working.
Thanks to the advice in comments.

I have made suitable changes to my original code and the following set up works well.
#Mock
UserUtil userUtil;
#InjectMocks
CustomServiceImpl cutomServiceImpl;
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
}
#Test
public void test01_getResultDto() {
when(userUtil.getCurrentUser()).thenReturn(null);
assertThatThrownBy(() -> customServiceImpl.getResultDto ("type", 1L))
.isInstanceOf(CustomException .class)
.hasMessage("User does not exist");
}

Another way you can do it is :
#MockBean
CustomServiceImpl customServiceImpl ;
#Rule
public ExpectedException exceptionRule = ExpectedException.none();
#Test
public void test01_getResultDto() {
exceptionRule.expect(CustomException.class);
UserUtil userUtil = Mockito.mock(UserUtil.class);
Mockito.when(userUtil.getCurrentUser()).thenReturn(null);
customServiceImpl.getResultDto ("type", 1L);
}

java.lang.NullPointerException is occuring due to property is not loading in Mockito when mocking a method

I am new to Mockito and i am facing a issue due to a property is not loading in from appication.properties file.
Problem statement: I am trying to mock a method which uses a property from the application.properties file. When the control arrives at the line to load property value it shows null and because of this mockito throws java.lang.NullPointerException.
What i am looking for is how to load the property from application.properties file when mocking a method.
Here i am trying to load global variable partsListGlobal .Please help me how to achieve this.?
Here is my below code snippet.
#Service
public class ClimoDiagnosticReportServImpl implements ClimoDiagnosticReportService {
#Value("${PARTS_LIST}")
private String partsListGlobal;
#Override
public boolean getSomeResult() {
String[] partsListLocal = getPartsList();
List<String> partsList = Arrays.asList(partsListGlobal);
if (partsList.contains("PART_X1"))
return true;
else
return false;
}
public String[] getPartsList() {
return partsListGlobal.split(",");// Here is the error occuring due to partsListGlobal is not loading the value from application.properties file.
}
}
#RunWith(MockitoJUnitRunner.class)
public class ClimoDiagnosticReportServImplTest {
#InjectMocks
private ClimoDiagnosticReportServImpl serviceReference1;
#Mock
private ClimoDiagnosticReportServImpl serviceReference12;
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void getSomeResultTest() {
boolean result1 = false;
String[] strArray = new String[2];
strArray[0] = "P1";
strArray[1] = "P2";
Mockito.when(serviceReference12.getPartsList()).thenReturn(strArray);
boolean result2 = serviceReference1.getSomeResult();
Assert.assertEquals(result1,result2);
}
}
Error:
java.lang.NullPointerException at
com.test.serviceimpl.ClimoDiagnosticReportServImpl.getPartsList(ClimoDiagnosticReportServImpl.java:68)
at
com.test.serviceimpl.ClimoDiagnosticReportServImpl.getSomeResult(ClimoDiagnosticReportServImpl.java:57)
at
com.test.serviceimpl.ClimoDiagnosticReportServImplTest.getSomeResultTest(ClimoDiagnosticReportServImplTest.java:74)
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.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at
org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at
org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Thanks everyone in advance.

You don't have any dependency to mock in the service. Mockito is thus completely unnecessary. What you need to do is to set the private String field, that is populated by Spring in your application using reflection.
Just follow the best practice os using cnstructor injection instead of field injection, and that will make your code testable (that's one of the reasons why it's a best practice):
#Service
public class ClimoDiagnosticReportServImpl implements ClimoDiagnosticReportService {
private String partsListGlobal;
public ClimoDiagnosticReportServImpl(#Value("${PARTS_LIST}") String partsListGlobal) {
this.partsListGlobal = partsListGlobal;
}
// ...
}
Your test now can be reduced to
public class ClimoDiagnosticReportServImplTest {
#Test
public void shouldReturnTrueIfPropertyContainsPartX1() {
ClimoDiagnosticReportServImpl service = new ClimoDiagnosticReportServImpl("a,b,c,PART_X1,d");
assertTrue(service.getSomeResult());
}
#Test
public void shouldReturnFalseIfPropertyDoesNotContainPartX1() {
ClimoDiagnosticReportServImpl service = new ClimoDiagnosticReportServImpl("a,b,c,d");
assertFalse(service.getSomeResult());
}
}

Spring junit test Error "could not find current request via RequestContextHolder"

I use spring framework 4 and have class that has his line :
String link = ServletUriComponentsBuilder.fromCurrentContextPath().path("/admin/menu/edit/"+id).build().toUriString();
Class perfectly run in on server but when I want to unit test it and create the class and call method that use above could got a error:
java.lang.IllegalStateException: Could not find current request via RequestContextHolder
at org.springframework.util.Assert.state(Assert.java:392)
at org.springframework.web.servlet.support.ServletUriComponentsBuilder.getCurrentRequest(ServletUriComponentsBuilder.java:190)
at org.springframework.web.servlet.support.ServletUriComponentsBuilder.fromCurrentContextPath(ServletUriComponentsBuilder.java:158)
at com.mohsenj.core.util.HiararchyUtils.createTableTrMenu(HiararchyUtils.java:175)
at com.mohsenj.core.util.HiararchyUtils.getHForTableMenu(HiararchyUtils.java:153)
at com.mohsenj.core.util.HiararchyUtils.getHForTableMenu(HiararchyUtils.java:158)
at com.mohsenj.core.util.HiararchyUtilsTest.getHForTableMenu_verifyReturnString(HiararchyUtilsTest.java:65)
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.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.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
my class:
#Component
public class HiararchyUtils {
public String getHForTableMenu(List<? extends Hierarchically> menus, Integer parentId) {
seperateParentsIntoAssoc(menus);
return createTableTrMenu(parentId, 0);
}
public String createTableTrMenu(Integer parent, Integer level) {
// some code
String link = ServletUriComponentsBuilder.fromCurrentContextPath().path("/admin/menu/edit/"+items.get(itemId).getId()).build().toUriString();
// some code
}}
test class :
#RunWith(MockitoJUnitRunner.class)
public class HiararchyUtilsTest {
private HiararchyUtils hiararchyUtils;
#Before
public void setup() {
hiararchyUtils = new HiararchyUtils();
}
#Test
public void getHForTableMenu_() {
String trs = hiararchyUtils.getHForTableMenu(menus);
}
}
what should I do?

It may be as easy as adding a MockHttpServletRequest in order to provide the needed RequestContextHolder and context path.
As a class variable, add
private MockHttpServletRequest mockRequest;
Then, when setting up your test(s), try:
#Before
mockRequest = new MockHttpServletRequest();
mockRequest.setContextPath("/your-app-context");
ServletRequestAttributes attrs = new ServletRequestAttributes(mockRequest);
RequestContextHolder.setRequestAttributes(attrs);
That should address that error.

Mocking a post request with Mockito throws NullPointerException on "when(event.request().getParam("type")).thenReturn("application/octet-stream");"

I'm trying to mock a file upload (using Vertx) with Mockito but it throws a NullPointerError on getParam("type") used in when(event.request().getParam("type")).thenReturn("application/octet-stream");
My unit test is as follows:
private UploadResultatenHandler uploadResultatenHandler;
#Mock
RoutingContext event;
File folder;
Set<io.vertx.ext.web.FileUpload> upload;
HttpServerRequest httpServerRequest;
HttpServerResponse httpServerResponse;
#Before
public void setUp() {
uploadResultatenHandler = new UploadResultatenHandler();
MockitoAnnotations.initMocks(this);
when(event.request().getParam("type")).thenReturn("application/octet-stream");
when(event.fileUploads()).thenReturn(upload);
when(httpServerResponse.setStatusCode(200)).thenReturn(httpServerResponse);
when(event.response()).thenReturn(httpServerResponse);
}
#Test
public void testCleanHandler() {
uploadResultatenHandler.handle(event);
verify(event).response();
}
"uploadResultatenHandler.handle(event);" :
#Override
public void handle(RoutingContext event) {
String newFileName = event.request().getParam("type");
Set<FileUpload> uploads = event.fileUploads();
System.out.println(uploads);
for (FileUpload fileUpload : uploads) {
String oldFileName = fileUpload.uploadedFileName();
char[] inhoud = FileReader.readFileUTF8ToString(oldFileName).toCharArray();
String fileExtention = setFileExtension(fileUpload.contentType());
FileCreater.createFile(newFileName, fileExtention, "file-uploads/", inhoud);
FileDeleter.deleteFile(oldFileName);
}
event.response().setStatusCode(200).end("Check");
}
private String setFileExtension(String type) {
switch (type) {
case "text/xml":
return ".xml";
case "application/octet-stream":
return ".json";
default:
return ".txt";
}
}
I think it might have something to do with the mocked RoutingContext not having this parameter, but I don't know how to fix / bypass this error?
I changed the line to when(event.request()).thenReturn(request); when(request.getParam("type")).thenReturn("application/oct‌​et-stream"); and the mocks to: Mock(answer = Answers.RETURNS_DEEP_STUBS) RoutingContext event; #Mock File folder; Set upload; HttpServerRequest request; HttpServerResponse response; but I'm still getting a NullPointer
Stack trace:
java.lang.NullPointerException
at nl.icaprojecten.TestIntegratieQuintor.ServiceLayer.rest.UploadResultatenHandlerTest.setUp(UploadResultatenHandlerTest.java:42)
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.RunBefores.evaluate(RunBefores.java:24)
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.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

Since you haven't recorded any behavior for event.request(), it will return null. Calling getParam on it will, of course, fail with a NullPointerException. There are a few ways around it, but the most elegant, IMHO, would be to use deep stubbing:
#Mock(answer = Answers.RETURNS_DEEP_STUBS)
RoutingContext event;

mocking does not work recursively.
you must split this line
when(event.request().getParam("type")).thenReturn("application/octet-stream");
to this
Request request = mock(Request.class);
when(event.request()).thenReturn(request);
when(request.getParam("type")).thenReturn("application/octet-stream");

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"));
}
}