@Test
public void testGetRole() {

    Attribute attribute = new Attribute("my.value");
    assertNull(attribute.getRole());
    Set<String> roles = new LinkedHashSet<String>();
    attribute.setRoles(roles);
    assertNull(attribute.getRole());
    roles.add("role1");
    roles.add("role2");
    assertEquals("role1,role2", attribute.getRole());
}