Mocking HttpSession using Mockito

Question

I need to test the following controller method:

@RequestMapping(value="/addLocation")
public String addLocation(HttpServletRequest request, HttpSession session) {

    String location = (String) request.getParameter("plz_ort");
    String radius = (String) request.getParameter("umkreis");

    ((ArrayList<String>) session.getAttribute("queryTopics")).clone();        

    ...
}

Therefor I wrote this test class using Mockito and JUnit

import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import java.util.ArrayList;

import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mock.web.MockHttpSession;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

public class MyControllerTest {


    @InjectMocks
    private MyController myController;

    private MockMvc mockMvc;

    @InjectMocks
    MockHttpSession session;

    @Before
    public void setup() {

        // Process mock annotations
        MockitoAnnotations.initMocks(this);

        // Setup Spring test in standalone mode
        this.mockMvc = MockMvcBuilders.standaloneSetup(MyController)
                .build();

    }

    @Test
    public void addLocation_StatusOK() throws Exception {
        session.setAttribute("queryTopics", new ArrayList<String>(0));

        this.mockMvc.perform(
                post("/addLocation")
                        .param("plz_ort", "PLZ ORT")
                        .param("umkreis", "5"))
                .andExpect(
                        status().isOk());

    }

}

As you can see I need to mock the session when running this test. When I debug through the code and stop at the line session.setAttribute("queryTopics", new ArrayList<String>(0)); the session object is org.springframework.mock.web.MockHttpSession@5583d693 (containing a attributes hash map {queryTopics=[]} ), so I think that's fine. However the session object of my next breakpoint in line ((ArrayList<String>) session.getAttribute("queryTopics")).clone(); is org.springframework.mock.web.MockHttpSession@7545a27f .

At least it's the correct type ( MockHttpSession ) but it's got a different ID so it's actually a whole new object and thus doesn't contain the session attributes from the test.

Could you please help me out on this one?

Answer 1

The mock MVC will create a spring mock request and a spring mock session and then invoke your controller method. In order to set some state in the session before the controller method is called, you need to configure the mock request using the builder:

public class MyControllerTest {

    @InjectMocks
    private MyController myController;

    private MockMvc mockMvc;

    @Before
    public void setup() {
        // Process mock annotations
        MockitoAnnotations.initMocks(this);

        // Setup Spring test in standalone mode
        this.mockMvc = MockMvcBuilders.standaloneSetup(MyController)
                .build();

    }

    @Test
    public void addLocation_StatusOK() throws Exception {
        this.mockMvc.perform(
                post("/addLocation")
                        .param("plz_ort", "PLZ ORT")
                        .param("umkreis", "5")
                        .sessionAttr("queryTopics", new ArrayList<String>(0))
                .andExpect(
                        status().isOk());
    }
}