Using Mockito with TestNG

I took a working test written for JUnit using Mockito and tried to adapt it to work with TestNG but oddly using TestNG only one test will work.

I think it is somehow related to the resetting of the mocks but I have played around with trying to call Mockito.reset and using BeforeMethod and BeforeClass and different combinations but still can only get one test to pass.

What I need to do to get the test to work?

@BeforeClass
public void setUp() {       
    MockitoAnnotations.initMocks(this);                                
    mockMvc = MockMvcBuilders.standaloneSetup(calculatorController).build();
}

@AfterMethod
public void setup() {
    Mockito.reset(calculatorService);
}

@Test
public void addFunctionTest() throws Exception {             
    Assert.assertNotNull(calculatorController);
     Result expectedResult = new Result();
     expectedResult.setResult(10);

    when(calculatorService.add(anyInt(), anyInt())).thenReturn(expectedResult);                             

    mockMvc.perform(get("/calculator/add").accept(MediaType.APPLICATION_JSON_VALUE)
            .param("val1", "100")
            .param("val2", "100"))  
    .andExpect(content().contentType("application/json"))
    .andExpect(status().isOk())
    .andExpect(jsonPath("$.result", equalTo(10)));    

    verify(calculatorService, times(1)).add(anyInt(), anyInt());
}   

@Test
public void subtractFunctionTest() throws Exception {            
    Assert.assertNotNull(calculatorController);
    Result expectedResult = new Result();
    expectedResult.setResult(90);

    when(calculatorService.subtract(anyInt(), anyInt())).thenReturn(expectedResult);                                

    mockMvc.perform(get("/calculator/subtract").accept(MediaType.APPLICATION_JSON_VALUE)
    .param("val1", "100")
    .param("val2", "10"))  
    .andExpect(content().contentType("application/json"))
    .andExpect(status().isOk())
    .andExpect(jsonPath("$.result", equalTo(90)));    

    verify(calculatorService, times(1)).subtract(anyInt(), anyInt());
}

The second test always seems to fail on assertions that either content type is not set or the expected result is wrong but I know the controller and service work as expected and the exact same tests running with jUnit actually work ok.