JUnit Mockito always returns false in assertEquals when comparing boolean values

Question

JUnit Mockito always returns false in assertEquals when comparing boolean values.

 @RunWith(MockitoJUnitRunner.class)
 public class UserServiceTest { 
    @Mock
    private UserService userService;

    @Mock
    private UserRepository userRepository;

    @Test
    public void testIsAccountBlocked() {
        Boolean accountBlocked = userService.isAccountBlocked("username");
        assertEquals(true, accountBlocked);
    }   
}

This method always return false even if the username is blocked. Why is it behaving like this?

Answer 1

There's no JUnit assertEquals with 2 booleans so you need to use different method - assertTrue :

Asserts that a condition is true. If it isn't it throws an AssertionError without a message.

assertTrue(accountBlocked);

But in your case your class is mocked and therefore by default all its method with Boolean return value will return false

By default, for all methods that return a value, a mock will return either null, a primitive/primitive wrapper value, or an empty collection, as appropriate. For example 0 for an int/Integer and false for a boolean/Boolean.

So unless you mock the method behavior using when you can assertFalse it

assertFalse(accountBlocked);

Answer 2

You aren't mocking any behavior. By default, calling a boolean method on a mock returns false.

To mock the behavior you are looking for:

Mockito.when(userService.isAccountBlocked("username")).thenReturn(true);