@Override
    public String toString() {
        return attributeName + " != " + value;
    }
@Test
    public void toString_containsAttributeName() {
        String fieldName = "name";
        NotEqualPredicate predicate = new NotEqualPredicate(fieldName, "foo");

        String result = predicate.toString();
        assertThat(result).contains(fieldName);
    }