mocking a static Spring boot controller method with powermokito

Question

One of my Spring boot controller method calls a static method. I want to test the controller using powermokito. Find below the code for the same. I'm getting an error when im trying call the mockMvc.perform() method @RunWith(PowerMockRunner.class)

@PrepareForTest({StaticClass.class})

public void StaticClassTests()

{

  @Autowired

  private MockMvc mockMvc;

  @Test

  public void testStatic()

  {

    List<String> list = new ArrayList<>();

    list.add("a");

    list.add("b");

    list.add("c");

    PowerMokito.when(StaticClass.getList()).thenReturn(list);

    RequestBuilder requestBuilder = MockMvcRequestBuilders.get("/getlist")
    .accept(MediaType.APPLICATION_JSON);

    MvcResult result = mockMvc.perform(requestBuilder)    //where the error is
            .andExpect(status().isOk())
            .andExpect(content().json("[\n" + 
                    " \"a\",\n" + 
                    " \"b\",\n" + 
                    " \"c\"\n" + 
                    "]"))
            .andReturn();

  }

}

StaticClass.getList() is a static method Im getting java.lang.NullPointerException at the commented line( i.e mockMvc.perform(requestBuilder))

Answer 1

You should initialize mockMvc before calling perform method.

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

Note: Inject your controller as here did for the CarSearchController

     @InjectMocks
     private CarSearchController carSearchController;