CODEWITHSUNDEEP
mockitojunit5
Zk_1990
Zk_1990

Reputation: 47

assertThrows() works well but it should fail

I'm new to junit and I'm wondering why assertThrows() works well in both of cases. Why does it throw an exception in the case of findById(1L)? There is an employee with an id 1L, so the assertion should fail. Am I right?

employee service:

public Employee findById(Long id) {
    return employeeRepository.findById(id)
            .orElseThrow( ()-> new NoSuchElementException("not found"));
}

Test method:

@ExtendWith(MockitoExtension.class)
class EmployeeManagerTest {

@Mock
private EmployeeRepository employeeRepository;

@InjectMocks
private EmployeeManager employeeManager;

@Test
void shouldThrowExceptionWhenEmployeeNotExist() {

Employee employee = new Employee();
employee.setId(1L);

assertThrows(NoSuchElementException.class, ()-> employeeManager.findById(123L) ); // works well

assertThrows(NoSuchElementException.class, ()-> employeeManager.findById(1L) ); // works well, but should fail, because there is an employee with id 1L
    
        }

}

Upvotes: 1

Views: 1479

Answers (1)

thchp
thchp

Reputation: 2384

You should mock your EmployeeRepository and make it return your employee when your EmployeeManager calls findById on the repository, or return nothing when you want to test the failing case. I created two separate tests:

@ExtendWith(MockitoExtension.class)
class EmployeeManagerTest {

    @Mock
    private EmployeeRepository employeeRepository;

    @InjectMocks
    private EmployeeManager employeeManager;

    @Test
    void shouldThrowExceptionWhenEmployeeDoesNotExist() {
        // Given
        
        // Make the repo return an empty optional when the id doesn't exit
        when(employeeRepository.findById(any())).thenReturn(Optional.empty());
        
        // Then
        assertThrows(NoSuchElementException.class, ()-> employeeManager.findById(123L) );
    }
    
    @Test
    void shouldReturnEmployeeWhenItExists() {
        // Given
        Employee employee =  new Employee();
        employee.setId(1L);
        
        // Make the repo return an the employee
        when(employeeRepository.findById(1L)).thenReturn(Optional.of(employee));
        
        // When
        Employee returnedEmployee = employeeManager.findById(1L);
        
        // Then
        assertEquals(employee, returnedEmployee);
    }

}

Upvotes: 1

Related Questions