Getting java.lang.NullPointerException for mvc.perform()

Question

I am new to unit testing in spring boot. I am trying to test a service and have used Mockito for it. When I do mvc.perform() I get a null value. I have used when() to specify what to return. But not sure why it fails. Please provide some valuable inputs. Here are fe snippets:

@Test
public void testAll() throws Exception {

    /*Mockito.when(sensorDao.findAll()).thenReturn((Iterable<Sensor>) s2);
    assertEquals(200,expect().statusCode(200));*/

    Collection<Sensor>list =  getEntityListStubData();
    when(sensorserviceimpl.findAll()).thenReturn(list);
    when(sensorService.findAll()).thenReturn(list);
    when(sensorDao.findAll()).thenReturn(list);
    String uri="/sensor";
    //System.out.print("gfnjhkjjhhg");
    System.out.println("Helllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllloooooooooooooooooooooooooooooooooooooooooooo");
    System.out.println(MockMvcRequestBuilders.get(uri).accept(MediaType.APPLICATION_JSON));
    MvcResult result = mvc.perform(MockMvcRequestBuilders.get(uri).accept(MediaType.APPLICATION_JSON)).andReturn();
    String content = result.getResponse().getContentAsString();
    int status = result.getResponse().getStatus();
 }

Here is the output:

2017-08-18 19:11:45.030  INFO 21424 --- [           main] o.s.t.c.transaction.TransactionContext   : Rolled back transaction for test context [DefaultTestContext@35083305 testClass = SensorServiceStandaloneApplicationTests, testInstance = com.bny.sr.sensorservicestandalone.SensorServiceStandaloneApplicationTests@482cd91f, testMethod = testAll@SensorServiceStandaloneApplicationTests, testException = java.lang.NullPointerException, mergedContextConfiguration = [WebMergedContextConfiguration@8e0379d testClass = SensorServiceStandaloneApplicationTests, locations = '{}', classes = '{class com.bny.sr.sensorservicestandalone.SensorServiceStandaloneApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{eureka.client.enabled:false, org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true, server.port=0}', contextCustomizers = set[org.springframework.boot.test.context.SpringBootTestContextCustomizer@167fdd33, org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@53f65459, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@74650e52, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@80503], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]]].

java.lang.NullPointerException
    at com.bny.sr.sensorservicestandalone.SensorServiceStandaloneApplicationTests.testAll(SensorServiceStandaloneApplicationTests.java:163)
    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:497)
    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: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$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$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)

2017-08-18 19:11:45.046  INFO 21424 --- [       Thread-5] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@5386659f: startup date [Fri Aug 18 19:11:34 IST 2017]; root of context hierarchy
2017-08-18 19:11:45.054  INFO 21424 --- [       Thread-5] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'

Process finished with exit code -1

Here is the debug result:

Debug results

Eddú Meléndez · Accepted Answer · 2017-08-18 14:27:52Z

5

Since spring-boot 1.4.0 you can use @WebMvcTest which will auto-configure MockMvc. Also, use @MockBean to mock any dependency in your controller.

@RunWith(SpringRunner.class)
@WebMvcTest(MyController.class)
public class MyControllerTest {

    @Autowired
    private MockMvc mvc;

    @MockBean
    private SensorDao sensorDao;

}

answered Aug 18, 2017 at 14:27

Eddú Meléndez

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2 Comments

Saurav Rath Over a year ago

Your answer gave a proper direction for me. @AutoConfigureMockMvc worked for me finally. The MockMvc requires to be auto configured. Thank You very much. :-)

HellishHeat Over a year ago

this is true for me also.

HellishHeat · Accepted Answer · 2021-03-29 14:32:45Z

1

@AutoConfigureMockMvc, will also do the trick

answered Mar 29, 2021 at 14:32

HellishHeat

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