[FIXED] How to test switch case in Junit using Mockito

Issue

I am able to test the code but code coverage does not cover second switch case.

Please refer the below code.

 { @PersistenceContext
    EntityManager manager;

    @Autowired
    TurbineRepository turbineRepository;

    @Autowired
    WorkRepository workRepository;

    public Dropdown getDropdown(String type) {
        Dropdown dropdownDTO = new Dropdown();
        switch(type) {
        case "turbine":
            List<String> turbinesList = turbineRepository.listOfTurbines();
            dropdownDTO.setTurbinesList(turbinesList);
            break;
        case "wocreate":
            List<String> turbineList = turbineRepository.listOfTurbines();
            dropdownDTO.setTurbinesList(turbineList);
            List<ParamsProjection> params = workRepository.findBy();
            Map<String, List<ParamsProjection>> result = params.stream()
                    .collect(Collectors.groupingBy(ParamsProjection::getType));
            dropdownDTO.setParams(result);
        default:
        }
        return dropdownDTO;

    }

Below is my test code.

{
    @InjectMocks
    private Services service;
    
    @Mock
    private WorkRepository workRepo;
    
    @Mock
    private TurbineRepository turbineRepo;
    
    @Mock
    private ParamsProjection paramProject1;
    
    @Test 
    public void getDropDown() {
        
        Dropdown dto = new Dropdown();
        List<String> turbineList = new ArrayList<String>();
        String type = "turbine";
        switch(type) {
        case "turbine" :
        Mockito.when(turbineRepo.listOfTurbines()).thenReturn(turbineList);
        dto.setTurbinesList(turbineList);
        assertNotNull(dto);
        break;
        
        case "wocreate": 
        DropdownDTO dto2 = new DropdownDTO();
        Mockito.when(turbineRepo.listOfTurbines()).thenReturn(turbineList);
        dto2.setTurbinesList(turbineList);
        List<ParamsProjection> param = new ArrayList<ParamsProjection>();
        Mockito.when(workRepo.findBy()).thenReturn(param);
        
        Map<String, List<ParamsProjection>> result = param.stream()
                .collect(Collectors.groupingBy(ParamsProjection::getType));
        
        dto2.setParams(result);
        assertNotNull(dto2);
        break;
}
        assertNotNull(service.getDropdown("turbine"));
}

As I have declared a string variable with value for testing , I am not able to cover the second switch statement. I have tried if-else case but same problem occurs. Is there any other way we can do this?

Solution

Your type is always "turbine", so just that case is tested. It would make sense to have two different tests, one for each type:

@Test 
public void getDropDownTurbine() {
    
    Dropdown dto = new Dropdown();
    List<String> turbineList = new ArrayList<String>();
    String type = "turbine";
    Mockito.when(turbineRepo.listOfTurbines()).thenReturn(turbineList);
    dto.setTurbinesList(turbineList);
    assertNotNull(dto);
    assertNotNull(service.getDropdown("turbine"));
} 


@Test 
public void getDropDown() {
    
    List<String> turbineList = new ArrayList<String>();
    String type = "wocreate";
    DropdownDTO dto2 = new DropdownDTO();
    Mockito.when(turbineRepo.listOfTurbines()).thenReturn(turbineList);
    dto2.setTurbinesList(turbineList);
    List<ParamsProjection> param = new ArrayList<ParamsProjection>();
    Mockito.when(workRepo.findBy()).thenReturn(param);
    
    Map<String, List<ParamsProjection>> result = param.stream()
            .collect(Collectors.groupingBy(ParamsProjection::getType));
    
    dto2.setParams(result);
    assertNotNull(dto2);

    assertNotNull(service.getDropdown("wocreate"));
} 

Answered By - Mureinik