java.lang.AssertionError: Content type not set while junit Spring MVC Controller?

Question

I am using JUnit to test my Spring MVC controller. Below is my method which returns a index.jsp page and shows Hello World on the screen -

@RequestMapping(value = "index", method = RequestMethod.GET)
public HashMap<String, String> handleRequest() {
    HashMap<String, String> model = new HashMap<String, String>();

    String name = "Hello World";
    model.put("greeting", name);

    return model;
}

And below is my JUnit test for the above method:

public class ControllerTest {

    private MockMvc mockMvc;

    @Before
    public void setup() throws Exception {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");

        this.mockMvc = standaloneSetup(new Controller()).setViewResolvers(viewResolver).build();
    }

    @Test
    public void test01_Index() throws Exception {

    mockMvc.perform(get("/index")).andExpect(status().isOk()).andExpect(content().contentType("application/json"))
        .andExpect(jsonPath("$.greeting").value("Hello World"));

    }
}

Above junit was working fine when I debugged it but when I ran the junit as run as junit, it gave me this error -

MockMvc : Circular view path [view]: would dispatch back to the current handler URL [/view] again

So to fix that I followed this tutorial and after that I am getting this exception -

java.lang.AssertionError: Content type not set
    at org.springframework.test.util.AssertionErrors.fail(AssertionErrors.java:39)
    at org.springframework.test.util.AssertionErrors.assertTrue(AssertionErrors.java:72)
    at org.springframework.test.web.servlet.result.ContentResultMatchers$1.match(ContentResultMatchers.java:75)
    at org.springframework.test.web.servlet.MockMvc$1.andExpect(MockMvc.java:141)
    at com.ebay.personalization.bullseye.zookeeper.test.ZookeeperControllerTest.test01_Index(ZookeeperControllerTest.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:76)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:602)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    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)

What am I doing wrong here? On the .jsp page it shows Hello World..

I am following up on my previous question here

Answer 1

I see a couple of issues with the request mapped method:

Ideally, you should have a @ResponseBody annotation on your method, to indicate that the returned content is to be streamed out:

@RequestMapping(value = "index", method = RequestMethod.GET)
@ResponseBody
public HashMap<String, String> handleRequest() {
    HashMap<String, String> model = new HashMap<String, String>();
    String name = "Hello World";
    model.put("greeting", name);

    return model;
}

Now with this done, your test can look like this:

mockMvc.perform(get("/index").contentType(MediaType.APPLICATION_JSON)).andExpect(status().isOk()).andExpect(content().contentTypeCompatibleWith("application/json"))
        .andExpect(jsonPath("$.greeting").value("Hello World"));

In your case, what is happening is Spring is trying to figure out the view name and is getting the view name as index, which is again the controller path, thus the circular view path error that you are seeing.