How to test validation annotations of a class using JUnit?

Question

I need to test the validation annotations but it looks like they do not work. I am not sure if the JUnit is also correct. Currently, the test will be passed but as you can s

Answer 1

First thanks @Eis for the answer, it helped me. It's a good way to fail the test, but I wanted a bit more "life-like" behaviour. At runtime an exception would be thrown so I came up with this:

/**
 * Simulates the behaviour of bean-validation e.g. @NotNull
 */
private void validateBean(Object bean) throws AssertionError {
    Optional> violation = validator.validate(bean).stream().findFirst();
    if (violation.isPresent()) {
        throw new ValidationException(violation.get().getMessage());
    }
}

Have an entity with validation:

@Data
public class MyEntity {

@NotBlank(message = "Name cannot be empty!")
private String name;

}

In a test you can pass an instance with invalid attributes and expect an exception:

private Validator validator;

@Before
public void setUp() {
    ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
    validator = factory.getValidator();
}

@Test(expected = ValidationException.class)
public void testValidationWhenNoNameThenThrowException() {
    validateBean(new Entity.setName(""));
}