How to unit test a Spring MVC controller using @Pa

Question

I have a simple annotated controller similar to this one:

@Controller
public class MyController {
  @RequestMapping("/{id}.html")
  public String doSomething(@PathVariable String id, Model model) {
    // do something
    return "view";
  }
}

and I want to test it with an unit test like this:

public class MyControllerTest {
  @Test
  public void test() {
    MockHttpServletRequest request = new MockHttpServletRequest();
    request.setRequestURI("/test.html");
    new AnnotationMethodHandlerAdapter()
      .handle(request, new MockHttpServletResponse(), new MyController());
    // assert something
  }
}

The problem is that AnnotationMethodHandlerAdapter.handler() method throws an exception:

java.lang.IllegalStateException: Could not find @PathVariable [id] in @RequestMapping
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter$ServletHandlerMethodInvoker.resolvePathVariable(AnnotationMethodHandlerAdapter.java:642)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolvePathVariable(HandlerMethodInvoker.java:514)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:262)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:146)

Answer 1

As of Spring 3.2, there is a proper way to test this, in an elegant and easy way. You will be able to do things like this:

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration("servlet-context.xml")
public class SampleTests {

  @Autowired
  private WebApplicationContext wac;

  private MockMvc mockMvc;

  @Before
  public void setup() {
    this.mockMvc = webAppContextSetup(this.wac).build();
  }

  @Test
  public void getFoo() throws Exception {
    this.mockMvc.perform(get("/foo").accept("application/json"))
        .andExpect(status().isOk())
        .andExpect(content().mimeType("application/json"))
        .andExpect(jsonPath("$.name").value("Lee"));
  }
}

For further information, take a look at http://blog.springsource.org/2012/11/12/spring-framework-3-2-rc1-spring-mvc-test-framework/

Answer 2

I'm not sure my original answer is going to help with @PathVariable. I've just tried testing an @PathVariable and I get the following exception:

org.springframework.web.bind.annotation.support.HandlerMethodInvocationException: Failed to invoke handler method [public org.springframework.web.servlet.ModelAndView test.MyClass.myMethod(test.SomeType)]; nested exception is java.lang.IllegalStateException: Could not find @PathVariable [parameterName] in @RequestMapping

The reason is that the path variables in the request get parsed by an interceptor. The following approach works for me:

import static org.springframework.test.web.ModelAndViewAssert.*;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"file:web/WEB-INF/application-context.xml",
        "file:web/WEB-INF/dispatcher-servlet.xml"})    
public class MyControllerIntegrationTest {

    @Inject
    private ApplicationContext applicationContext;

    private MockHttpServletRequest request;
    private MockHttpServletResponse response;
    private HandlerAdapter handlerAdapter;

    @Before
    public void setUp() throws Exception {
        this.request = new MockHttpServletRequest();
        this.response = new MockHttpServletResponse();

        this.handlerAdapter = applicationContext.getBean(HandlerAdapter.class);
    }

    ModelAndView handle(HttpServletRequest request, HttpServletResponse response)
            throws Exception {
        final HandlerMapping handlerMapping = applicationContext.getBean(HandlerMapping.class);
        final HandlerExecutionChain handler = handlerMapping.getHandler(request);
        assertNotNull("No handler found for request, check you request mapping", handler);

        final Object controller = handler.getHandler();
        // if you want to override any injected attributes do it here

        final HandlerInterceptor[] interceptors =
            handlerMapping.getHandler(request).getInterceptors();
        for (HandlerInterceptor interceptor : interceptors) {
            final boolean carryOn = interceptor.preHandle(request, response, controller);
            if (!carryOn) {
                return null;
            }
        }

        final ModelAndView mav = handlerAdapter.handle(request, response, controller);
        return mav;
    }

    @Test
    public void testDoSomething() throws Exception {
        request.setRequestURI("/test.html");
        request.setMethod("GET");
        final ModelAndView mav = handle(request, response);
        assertViewName(mav, "view");
        // assert something else
    }

I've add a new blog post on integration testing spring mvc annotations

Answer 3

I'd call what you're after an integration test based on the terminology in the Spring reference manual. How about doing something like:

import static org.springframework.test.web.ModelAndViewAssert.*;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({/* include live config here
    e.g. "file:web/WEB-INF/application-context.xml",
    "file:web/WEB-INF/dispatcher-servlet.xml" */})
public class MyControllerIntegrationTest {

    @Inject
    private ApplicationContext applicationContext;

    private MockHttpServletRequest request;
    private MockHttpServletResponse response;
    private HandlerAdapter handlerAdapter;
    private MyController controller;

    @Before
    public void setUp() {
       request = new MockHttpServletRequest();
       response = new MockHttpServletResponse();
       handlerAdapter = applicationContext.getBean(HandlerAdapter.class);
       // I could get the controller from the context here
       controller = new MyController();
    }

    @Test
    public void testDoSomething() throws Exception {
       request.setRequestURI("/test.html");
       final ModelAndView mav = handlerAdapter.handle(request, response, 
           controller);
       assertViewName(mav, "view");
       // assert something
    }
}

For more information I've written a blog entry about integration testing Spring MVC annotations.

Answer 4

A promising framework for testing Spring MVC https://github.com/SpringSource/spring-test-mvc

Answer 5

Provided you are using Spring 3.0.x.

Here I suggest a merger of Emil and scarba05 answers using spring-test not spring-test-mvc. Please skip this answer and refer to spring-test-mvc examples if you are using Spring 3.2.x or later

MyControllerWithParameter.java

@Controller
public class MyControllerWithParameter {
@RequestMapping("/testUrl/{pathVar}/some.html")
public String passOnePathVar(@PathVariable String pathVar, ModelMap model){
    model.addAttribute("SomeModelAttribute",pathVar);
    return "viewName";
}
}

MyControllerTest.java

import static org.springframework.test.web.ModelAndViewAssert.assertViewName;
import java.util.HashMap;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.web.ModelAndViewAssert;
import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = 
    {"file:src\\main\\webapp\\WEB-INF\\spring\\services\\servlet-context.xml" 
    })
public class MyControllerTest {

private MockHttpServletRequest request;
private MockHttpServletResponse response;
private HandlerAdapter handlerAdapter;

@Before
public void setUp() throws Exception {
    request = new MockHttpServletRequest();
    response = new MockHttpServletResponse();
    this.handlerAdapter = applicationContext.getBean(AnnotationMethodHandlerAdapter.class);
}

//  Container beans
private MyControllerWithParameter myController;
private ApplicationContext applicationContext;
public ApplicationContext getApplicationContext() {
    return applicationContext;
}
@Autowired
public void setApplicationContext(ApplicationContext applicationContext) {
    this.applicationContext = applicationContext;
}
public MyControllerWithParameter getMyController() {
    return myController;
}
@Autowired
public void setMyController(MyControllerWithParameter myController) {
    this.myController = myController;
}

@Test
public void test() throws Exception {
    request.setRequestURI("/testUrl/Irrelavant_Value/some.html");
    HashMap<String, String> pathvars = new HashMap<String, String>();
    // Populate the pathVariable-value pair in a local map
    pathvars.put("pathVar", "Path_Var_Value");
    // Assign the local map to the request attribute concerned with the handler mapping 
    request.setAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, pathvars);

    final ModelAndView modelAndView = this.handlerAdapter.handle(request, response, myController);

    ModelAndViewAssert.assertAndReturnModelAttributeOfType(modelAndView, "SomeModelAttribute", String.class);
    ModelAndViewAssert.assertModelAttributeValue(modelAndView, "SomeModelAttribute", "Path_Var_Value");
    ModelAndViewAssert.assertViewName(modelAndView, "viewName");
}

}

Answer 6

The exception message refers to a "feed" variable, which isn't present in your sample code, it's likely being caused by something you haven't shown us.

Also, your test is testing Spring and your own code. Is this really what you want to do?

It's better to assume that Spring works (which it does), and just test your own class, i.e. call MyController.doSomething() directly. That's one benefit of the annotation approach - you don't need to use mock requests and responses, you just use domain POJOs.