Spring MVC application Junit test case failing

Question

My JUnit test case is failing. Error is occurring at line

Mockito.when(blogEntryService.find(1L)).thenReturn(entry);

Failure trace is

java.lang.NullPointerException at com.sample.controller.BlogEntryControllerTest.getExistingBlogEntry(BlogEntryControllerTest.java:72) 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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87) 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:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176) 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:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

it seems to me that blogEntryService is null

My code is

    /**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" width="100%">
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.controller;

import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.forwardedUrl;

import org.hamcrest.Matchers;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import com.sample.config.ApplicationConfig;
import com.sample.model.BlogEntry;
import com.sample.service.BlogEntryService;

/**
 * @author EOV537 -
 * @since 1.0
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {ApplicationConfig.class})
@WebAppConfiguration
public class BlogEntryControllerTest {

    private MockMvc mockMvc;

    @InjectMocks
    private BlogEntryController blogentryconttroller;

    @Mock
    private BlogEntryService blogEntryService;

    @Autowired
    private WebApplicationContext appCtx;

    @Before
    public void setup() {

        MockitoAnnotations.initMocks(BlogEntryControllerTest.class);
        mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();
    }

    @Test
    public void getExistingBlogEntry() throws Exception {

        BlogEntry entry = new BlogEntry();
        entry.setId(1L);
        entry.setTitle("Test Title");

        Mockito.when(blogEntryService.find(1L)).thenReturn(entry);

        mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-entries/1"))
                .andExpect(MockMvcResultMatchers.jsonPath("$.title", Matchers.is("Test Title")))
                .andExpect(
                        MockMvcResultMatchers.jsonPath("$.links[*].href",
                                Matchers.hasItem(Matchers.endsWith("/blog-entries/1"))))
                .andExpect(MockMvcResultMatchers.status().isOk());
    }

    public void getNonExistingBlogEntry() throws Exception {

        Mockito.when(blogEntryService.find(1L)).thenReturn(null);
        mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-entries/1")).andExpect(
                MockMvcResultMatchers.status().isNotFound());
    }



}

BlogEntryController.Java

package com.sample.controller;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.sample.assembler.BlogEntryResourceAsm;
import com.sample.model.BlogEntry;
import com.sample.resource.BlogEntryResource;
import com.sample.service.BlogEntryService;

/**
 * @author EOV537 -
 * @since 1.0
 */
@Controller
@RequestMapping(value = "/rest/blog-enteries")
public class BlogEntryController {

    public BlogEntryController() {

    }

    public BlogEntryController(BlogEntryService blogEntryService) {

        this.blogEntryService = blogEntryService;
    }

    private BlogEntryService blogEntryService;

    @RequestMapping(value = "/{blogEntryId}", method = RequestMethod.GET)
    public ResponseEntity<BlogEntryResource> getExsitingBlogEntry(@PathVariable Long blogEntryId) {

        BlogEntry entry = blogEntryService.find(blogEntryId);

        if (entry != null) {
            BlogEntryResource res = new BlogEntryResourceAsm().toResource(entry);
            return new ResponseEntity<BlogEntryResource>(res, HttpStatus.OK);
        } else {
            return new ResponseEntity<BlogEntryResource>(HttpStatus.NOT_FOUND);
        }
    }

}

BlogEntryService.Java

package com.sample.service;

import org.springframework.stereotype.Component;

import com.sample.model.BlogEntry;

/**
 * @author EOv537 -
 * 
 * @since 1.0
 */

public interface BlogEntryService {
    public BlogEntry find(Long id);
}

BlogEntryResource.java

package com.sample.resource;

import org.springframework.hateoas.ResourceSupport;

/**
 * @author EOv537 -
 * @since 1.0
 */
public class BlogEntryResource extends ResourceSupport {

    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

}

BlogEntryResourceAsm.java

public class BlogEntryResourceAsm extends ResourceAssemblerSupport<BlogEntry, BlogEntryResource> {

    /**
     * @param controllerClass
     * @param resourceType
     */
    public BlogEntryResourceAsm() {
        super(BlogEntryController.class, BlogEntryResource.class);
        // TODO Auto-generated constructor stub
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.hateoas.ResourceAssembler#toResource(java.lang.Object)
     */
    @Override
    public BlogEntryResource toResource(BlogEntry blogEntry) {

        BlogEntryResource res = new BlogEntryResource();
        res.setTitle(blogEntry.getTitle());
        Link link = ControllerLinkBuilder.linkTo(BlogEntryController.class).slash(blogEntry.getId()).withSelfRel();
        return res;

    }
}

ApplicationConfig.java

/**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" width="100%">
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

/**
 * @author EOV537 -
 * @since 1.0
 */
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.sample"})
public class ApplicationConfig extends WebMvcConfigurerAdapter {

    private static final String VIEW_RESOLVER_PREFIX = "/WEB-INF/jsp/";

    private static final String VIEW_RESOLVER_SUFFIX = ".jsp";

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("/static/");
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();

        // viewResolver.setViewClass(InternalResourceViewResolver.class); // NOSONAR
        viewResolver.setPrefix(VIEW_RESOLVER_PREFIX);
        viewResolver.setSuffix(VIEW_RESOLVER_SUFFIX);

        return viewResolver;
    }

}

WebApplint.java

/**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" width="100%">
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.config;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * @author EOV537 -
 * @since 1.0
 */
public class WebApplint implements WebApplicationInitializer {
    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.web.WebApplicationInitializer#onStartup(javax.servlet.ServletContext)
     */
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {

        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(ApplicationConfig.class);

        ServletRegistration.Dynamic registration = servletContext.addServlet("DispatcherServlet",
                new DispatcherServlet(rootContext));

        registration.addMapping("/");

        registration.setLoadOnStartup(1);
        servletContext.addListener(new ContextLoaderListener(rootContext));

    }
}

abcdef12 · Accepted Answer · 2016-01-29 08:00:18Z

1

private MockMvc mockMvc;

@Autowired
@InjectMocks
private BlogEntryController blogentryconttroller;

@Autowired
private WebApplicationContext appCtx;

@Mock
BlogEntryService blogEntryService;

@Before
public void setup() {
    MockitoAnnotations.initMocks(BlogEntryControllerTest.this);
    mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();
}

@Test
public void getExistingBlogEntry() throws Exception {
    BlogEntry entry = new BlogEntry();
    entry.setId(1L);
    entry.setTitle("Test Title");
    Mockito.when(blogEntryService.find(1L)).thenReturn(entry);
    mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-enteries/1"))
            .andExpect(MockMvcResultMatchers.status().isOk());
}

edited Jan 29, 2016 at 8:00

answered Jan 24, 2016 at 16:23

abcdef12

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8 Comments

Satya Over a year ago

I want to use annotations @Mock private BlogEntryService blogEntryService; if you see the class I already have that is that approach is not correct?

Satya Over a year ago

using your solution BlogEntryService blogEntryService = Mockito.mock(BlogEntryService.class); Mockito is giving me proxy implementation, I don't need to add implementation and intialize but I never understood why @mock did not work.

Satya Over a year ago

I did initialize see my code MockitoAnnotations.initMocks(BlogEntryControllerTest.class);

Satya Over a year ago

with your solution I am able to move forward 1 step but after test execution it is still failing 2016-01-24 11:21:21 DEBUG TestDispatcherServlet:984 - Could not complete request java.lang.NullPointerException at com.sample.controller.BlogEntryController.getExsitingBlogEntry(BlogEntryController.java:49)

Satya Over a year ago

I don't have service implementation that is why I am using mock. Here is link to my repository github.com/satyajitn/rest-service I am doing test driven development so writing test cases before service implemenation

|

Patrick · Accepted Answer · 2016-01-24 16:26:08Z

0

In BlogEntryController(), blogEntryService is never initialized with a value. in your @Before (setup()) method, initialize blogEntryService:

blogEntryService = new BlogEntryService();

answered Jan 24, 2016 at 16:26

Patrick

1841 silver badge11 bronze badges

1 Comment

Satya Over a year ago

blogEntryService is Interface it can not be resolved into variable. Please see the code

Satya · Accepted Answer · 2016-01-24 19:06:55Z

Rohit's Answer above helped and resolve original mocking issue following was alternative I tried and it work, but it is just alternative not the solution.

I commented following line

//@RunWith(SpringJUnit4ClassRunner.class)
//@ContextConfiguration(classes = {ApplicationConfig.class})

from BlogEntryControllerTest.java

I changed setup() method from BlogEntryControllerTest to

@Before
public void setup() {

    // blogEntryService = Mockito.mock(BlogEntryService.class);
    MockitoAnnotations.initMocks(this);
    mockMvc = MockMvcBuilders.standaloneSetup(blogentryconttroller).build();
    //mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();

}

Instead of webAppContextSetup it is change to StandaloneSetup and then

updated BlogEntryController and removed default constructor

// public BlogEntryController() {

// }

now there is only 1 constructor

public BlogEntryController(BlogEntryService blogEntryService) {
    this.blogEntryService = blogEntryService;
}

Now when I am executing test mocked blogEntryService is getting injected properly.

When I was using webAppContextSetup then I have to keep default constructor for BlogEntryController. Since it had default constructor, so when I ran test default constructor get executed and blogEntryService remain null and test fail.

Even though I am able to get this working, this is not solution it is just a alternative.

if Someone know how to get this issue resole with webAppContextSetup please post solution.

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