Getting NullPointerEXception using Mockito Test case error 400

Question

I'm Adding 3 Categories using Post Request and for every Category, 3 respective Courses are added to the same. Finally I need to get an array of Categories containing list of courses. But while performing Test Driven Development using Mockito, I', recieving a null Pointer Exception with status code 400. Kindly help me in the same.

Test.java

@RunWith(value = MockitoJUnitRunner.class)
@WebMvcTest(Controller.class)
class Test {

    @Autowired
    MockMvc mvc;

    @MockBean
    service s;

    @MockBean
    Controller cont;

    @MockBean
    StatusResultMatchers sr;

    @org.junit.jupiter.api.Test
    void catTest() throws Exception {
        Course c1=new Course(1,"Technology",100,50,7415);
        Course c2=new Course(2,"Technology",100,50,7415);
        Course c3=new Course(3,"Technology",100,50,7415);
        Course[] c= {c1,c2,c3};
        List<Course> cl=new ArrayList<Course>();
        cl.add(c1);
        cl.add(c2);
        cl.add(c3); 
        Category ca=new Category(7415,"java","very gud", cl);

        when(s.getAllContents()).thenReturn(cl);
        mvc.perform(get("/getcourse")).andExpect(sr.is2xxSuccessful()).andReturn();
    }

}

Controller.java

@RestController
public class Controller {

      @Autowired
      private service cs;


      @RequestMapping(value="/addcat", method=RequestMethod.POST)
      public void addcat(@RequestBody Category[] categ) throws Exception{
          for(int i=0;i<3;i++)
            cs.cat[i]=categ[i];  
      }

    @RequestMapping(value="/addcour", method=RequestMethod.POST)
      public void addcour(@RequestBody Course[] cour) {
        for(Category c:cs.cat) {
            cs.co=null;
            for(int i=0;i<3;i++) {
                if(cour[i].getCategoryId()==c.getCategoryId()) {
                    cs.co.add(cour[i]);
                    c.setCourseList(cs.co);
                }
            }
        }
    }

    @RequestMapping(value="/getcat", method=RequestMethod.GET)
      public @ResponseBody Category[] getcat(){
        return cs.getAllCategories();
     }

    @RequestMapping(value="/getcourse", method=RequestMethod.GET)
      public @ResponseBody List<Course> getcourse(@RequestBody Map<Category,List<Course> > cour){
        return cs.getAllContents();
     }

}

Service.java

@Service
public class service {

    public List<Course> co=new ArrayList<Course>();
    public  Category[] cat=new Category[3];
    public List<Course>  getAllContents() {
        return co;
    }
    public Category[] getAllCategories() {
        return cat;
    }
}

Test Output

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /getcourse
       Parameters = {}
          Headers = []
             Body = <no character encoding set>
    Session Attrs = {}

Handler:
             Type = com.example.demo.controller.Controller$MockitoMock$138133307
           Method = com.example.demo.controller.Controller$MockitoMock$138133307#getcourse(Map)

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = org.springframework.http.converter.HttpMessageNotReadableException

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 400
    Error message = null
          Headers = []
     Content type = null
             Body = 
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
2020-06-03 17:38:59.573  INFO 26360 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

I have updated my code. Now, NullPOinterException is not there. But I'm getting an empty list "ActualCourse". Please find d code below:

Test.java

@RunWith(value = MockitoJUnitRunner.class)

@WebMvcTest(Controller.class) class Test {

@Autowired
MockMvc mvc;

@MockBean
service testService;

@MockBean
Controller targetController;

@Before
public void setup() {
    MockitoAnnotations.initMocks(this);
}

@org.junit.jupiter.api.Test
void catTest() throws Exception  {
    // Mock Data
    Course c1=new Course(1,"Technology",100,50,7415);
    Course c2=new Course(2,"Technology",100,50,7415);
    Course c3=new Course(3,"Technology",100,50,7415);

    List<Course> expectedCourse=new ArrayList<Course>();
    expectedCourse.add(c1);
    expectedCourse.add(c2);
    expectedCourse.add(c3); 

    Category expectedCategory=new Category(7415,"java","very gud", expectedCourse);

    when(testService.addcour()).thenReturn(expectedCourse);     
    List<Course> actualCourse = targetController.addcour();     
    assertEquals(expectedCourse,actualCourse);
}

Controller.java

@RestController
public class Controller {

  @Autowired
  private service cs;


  @RequestMapping(value="/addcat", method=RequestMethod.POST)
  public List<Category> addcat(@RequestBody Category[] categ) throws Exception{
      return cs.addcat(categ);
  }

@RequestMapping(value="/addcour", method=RequestMethod.POST)
  public List<Course> addcour() {
    return cs.addcour();
}

@RequestMapping(value="/getcat", method=RequestMethod.GET)
  public @ResponseBody List<Category> getcat(){
    return cs.getAllCategories();
 }

@RequestMapping(value="/getcourse", method=RequestMethod.GET)
  public @ResponseBody List<Course> getcourse(){
    return cs.getAllCourses();
 }
 }

Service.java

@Service
public class service {

public List<Category> cat=new ArrayList<Category>();
public List<Course> c=new ArrayList<Course>();

List<Course> empty=new ArrayList<Course>();
List<Category> category=new ArrayList<Category>();

public List<Category> addcat(Category[] categ) {
    int flagcat=0,flagcourse=0;

    Category c1=new Category(7415,"Technology","Java",empty);
    Category c2=new Category(2,"Technology","Java",empty);
    Category c3=new Category(7314,"Technology","Java",empty);

    Category c4=new Category(4,"Technology","Java",empty);
    Category c5=new Category(8415,"Technology","Java",empty);
    Category c6=new Category(6,"Technology","Java",empty);

    category=Arrays.asList(c1,c2,c3,c4,c5,c6);
    Iterator icat=category.iterator();
    Iterator icourse=c.iterator();

    Object ncourse=new Object();
    Object ncat=new Object();

    while(icat.hasNext()) {
        List<Course> co=new ArrayList<Course>();

        flagcat++;
        flagcourse=0;

        ncat=icat.next();

        while(icourse.hasNext()) {
            ncourse=icourse.next();

            if(((Category) ncourse).getCategoryId()==((Category) ncat).getCategoryId()) {
                flagcourse++;
                co.add((Course) ncourse);
                if(flagcourse==3) {
                    ((Category) ncat).setCourseList(co);
                    break;
                }
            }
        }
        cat.add((Category) icat);
        if(flagcat==3) {
            break;
        }
    }
    return cat;

}

public List<Course> addcour() {
    Course c1=new Course(1,"Technology",100,50,7415);
    Course c2=new Course(2,"Technology",100,50,7415);
    Course c3=new Course(3,"Technology",100,50,7415);

    Course c4=new Course(4,"Technology",100,50,7314);
    Course c5=new Course(5,"Technology",100,50,7314);
    Course c6=new Course(6,"Technology",100,50,7314);   

    Course c7=new Course(7,"Technology",100,50,8415);
    Course c8=new Course(8,"Technology",100,50,8415);
    Course c9=new Course(9,"Technology",100,50,8415);
    Course c10=new Course(10,"Technology",100,50,8415);

    List<Course> c=Arrays.asList(c1,c2,c3,c4,c5,c6,c7,c8,c9,c10);
    return c;
}

public List<Course> getAllCourses() {

    return c;
}
public List<Category> getAllCategories() {
    return cat;
}
}

Output

org.opentest4j.AssertionFailedError: expected: <[com.example.demo.Course@6ecc02bb, com.example.demo.Course@31973858, com.example.demo.Course@65514add]> but was: <[]>
at org.junit.jupiter.api.AssertionUtils.fail(AssertionUtils.java:55)
at org.junit.jupiter.api.AssertionUtils.failNotEqual(AssertionUtils.java:62)
at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:182)
at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:177)
at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:1124)
at com.example.demo.test.Test.catTest(Test.java:75)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:686)
at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:212)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:208)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:137)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:71)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1507)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1507)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:229)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:197)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:137)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.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:542)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:770)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:464)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)

score 1 · Accepted Answer · answered Jun 08 '20 at 00:01

1

It seems you have some design issues in your code. In your controller, the getcourse method is receiving a request body Map<Category,List<Course> > cour, but the HTTP method is a GET, you're not supposed to send data in a GET method (check this answer and this for more context).

On the other side, your getcourse is not using the cour parameter, so refactor this method as:

@RequestMapping(value="/getcourse", method=RequestMethod.GET)
public @ResponseBody List<Course> getcourse(){
        return cs.getAllContents();
}

Let me know if it works.

answered Jun 08 '20 at 00:01

CarlosJavier

1,005
1
16
29

I have updated my code above. Please have a look and kindly help – Khushank Sethi Jun 08 '20 at 10:02
I think the original question was answered as your code is not returning a 400. Please mark the question as answered. Regarding your actual problem, please carefully check the logic in your catTest() method, in the line assertEquals(expectedCourse,actualCourse); the method is validating the two objects expectedCourse and actualCourse to be the same AND NOT THE CONTENT of the arrays, you should iterate over the collections if you want to compare each entry. The two objects are created in different lines of the method, so they two different objects, the assert will fail. – CarlosJavier Jun 08 '20 at 13:07
If so, then actualCourse should should contain a list of 10 objects. But, it is showing an empty list – Khushank Sethi Jun 10 '20 at 08:19

Getting NullPointerEXception using Mockito Test case error 400

1 Answers1