How to mock controller parameter method with Mockito? - spring-boot

Question

I have the following controller method where criterias is an object build with query parameters :
#GetMapping
public List<Employee> findAll(CustomCriteria criterias) {
// this method build a custom mongoDB query object
final Query query = criterias.buildMongoDBQueryFromCriteria();
return employeeService.find(query);
}
The test is written as follow :
#Test
void get_all_employees_with_criterias() {
given(employeeService.find(any(Query.class)))
.willReturn(List.of(new Employee(), new Employee));
final var responseBody = mvc.perform(get("/employees?companyId=12,14")
.accept(MediaType.APPLICATION_JSON))
.andExpect(status().isOk())
.andReturn()
.getResponse().getContentAsString();
assertThatJson(responseBody).isArray().size().isEqualTo(2);
}
I can't find how to mock criterias.buildMongoDBQueryFromCriteria(). Indeed, there are a lot of logic inside this method, and I don't want it to be called for real with #WebMvcTest.
I have already tried to use #Spy annotation in the controller test class but it doesn't seems to work :/
I'm pretty sure that it must be really basic, but I didn't find any equivalent needs over Google.
Thanks for your help
EDIT
Based on #nnhthuan response I updated my test as follow, but it still doesn't work:
#Test
void get_all_employees_with_criterias() {
var customCriteriaMock = Mockito.mock(CustomCriteria.class);
var mockedQuery = Mockito.mock(Query.class);
when(customCriteriaMock.buildMongoDBQueryFromCriteria()).thenReturn(mockedQuery);
given(employeeService.find(mockedQuery))
.willReturn(List.of(new Employee(), new Employee()));
final var responseBody = mvc.perform(get("/employees?companyId=12,14")
.accept(MediaType.APPLICATION_JSON))
.andExpect(status().isOk())
.andReturn()
.getResponse().getContentAsString();
assertThatJson(responseBody).isArray().size().isEqualTo(2);
}

Answer 1

If you're asking how to write unit test, and this is how, not what you're trying to write above.
#Test
public void testFindAll() {
CustomCriteria mockCriteria = Mockito.mock(CustomCriteria.class);
Query mockQuery = Mockito.mock(Query.class);
List<Employee> expectation = new ArrayList<>();
when(mockCriteria.buildMongoDBQueryFromCriteria()).thenReturn(mockQuery);
when(employeeService.find(mockQuery)).thenReturn(expectaion)
List<Employee> actual = controller.findAll(mockCriteria);
assertThat(actual).sameInstance(expectation); // Or whatever framework you are using to assert.
}
If you're asking how to write integration test with your real service, so do not use mocking framework. :)