SpringMVC- Mockito- Junit - NullPointerException when service class method is called from controller class - spring

Question

I am writing a web-application, by using spring MVC . I have made a service class to map things to and from the database using UI.
My problem is I am new to junit and mockito
when i am trying to write unit tests on Controller class, it always returns a NullPointerException. It is really annoying since I am unable to find the answer, so I hope you guys can help me out. Below I have posted my code.
My Controller class method on /update return success
#RequestMapping(value = "/update", method = RequestMethod.POST)
public String updateFormData(#ModelAttribute CRDetails certGuide,
ModelMap model) {
crService.updateCertification(certGuide);
return "success";
}
My Service class method updates mongodb with modified data
public void updateCertification(CRDetails certGuide) { String userTypeSubmitted = certGuide.getCertGuidelines().getUserType(); System.out.println("updated by " + userTypeSubmitted); Update update = new Update(); Query query = new Query(Criteria.where("cr").is("CR1"));
CRDetails details = certMongoTemplate.findOne(query, CRDetails.class,
COLLECTION_NAME); CertificateGuidelines newCertGuide = new CertificateGuidelines();
if (details != null) { newCertGuide.setCertG(certGuide.getCertGuidelines().getCertG()); if (userTypeSubmitted.equals("Certification Team")
&& userTypeSubmitted != "") {
newCertGuide.setStatus("Pending with Document Developer"); } else {
newCertGuide.setStatus("Pending with Certification Team"); } newCertGuide.setHistoryCount(++count);
// converting it into mongo document. MongoConverter converter = certMongoTemplate.getConverter(); DBObject newRec = (DBObject) converter
.convertToMongoType(newCertGuide); update.set("certGuidelines", newRec); }
System.out.println("new cert guide " + newCertGuide.getCertG() + " "
+ newCertGuide.getStatus() + " "
+ newCertGuide.getHistoryCount() + " "
+ newCertGuide.getUserType());
certMongoTemplate.updateFirst(query, update, CRDetails.class); }
My controllerTest class which return NullPointerException.
import static org.junit.Assert.assertEquals;
import org.junit.Before;
import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.springframework.test.web.server.MockMvc;
import org.springframework.ui.ModelMap;
import org.springframework.web.servlet.View;
import com.cerner.docworks.controller.CRController;
import com.cerner.docworks.domain.CRDetails;
import com.cerner.docworks.service.CRService;
public class CRControllerTest {
/*#Mock private CRService service;*/
#Mock View mockView;
#InjectMocks
private CRController crController;
private MockMvc mockMvc;
#Before public void setup() {
}
#Test public void testUpdate() throws Exception { // CRService service = Mockito.mock(CRService.class); CRService crService = Mockito.spy(new CRService()); ModelMap model = Mockito.mock(ModelMap.class); CRDetails certGuide = Mockito.spy(new CRDetails());
CRController controller = new CRController();
// Mockito.when(service.updateCertification(certGuide)); // Mockito.when(model.addAttribute(Matchers.eq("certGuide"),any(String.class))).thenReturn(null); // Mockito.doThrow(new RuntimeException()).when(crService).updateCertification(certGuide); Mockito.doNothing().when(crService).updateCertification(certGuide); Mockito.mockingDetails(certGuide); // Mockito.doCallRealMethod().when(crService).updateCertification(certGuide); // Mockito.(crService)).updateCertification(certGuide);; String fileName = controller.updateFormData(certGuide, model);
System.out.println(fileName); // Mockito.verify(controller).updateFormData(certGuide, model); assertEquals("success", fileName); } }
Trace:
java.lang.NullPointerException at
com.cerner.docworks.controller.CRController.updateFormData(CRController.java:81)
at
com.cerner.docworks.controller.test.CRControllerTest.testUpdate(CRControllerTest.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:483) 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.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
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:675)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
FYI,
CRDetails is a pojo class with
private String id;
private String cr;
private String desc;
private CertificateGuidelines certGuidelines;
private Date dueDate;
//private String userType;
private String solutionName;
FYI,
When i am debugging the code, i found mock is setting objects to null
If i do set details manually, test case pass but, i want to use mockito.
Thanks in advance for ur help.

Answer 1

You need to run the test with the MockitoJUnitRunner, e.g.:
#RunWith(MockitoJUnitRunner.class)
public class CRControllerTest {
// ...
This allows #InjectMocks and #Mock to work properly. I.e. mockView will be created as a mock of View and crController will be created with relevant #Mock-annotated fields.
You can refer to the documentation to see how the mocks are injected.