@Test
public void getRootType() {

    SimpleTypeImpl simpleTypeAny = new SimpleTypeImpl(null, "tSimple", null, false, Collections.emptyList(), null, BuiltInType.UNKNOWN);
    assertEquals(BuiltInType.UNKNOWN, DMNUtils.getRootType(simpleTypeAny));
    Type aliasFeelType = new AliasFEELType("alias", BuiltInType.UNKNOWN);
    CompositeTypeImpl aliasType = new CompositeTypeImpl(null, "tSimple", null, false, Collections.emptyMap(), simpleTypeAny, aliasFeelType);
    assertEquals(BuiltInType.UNKNOWN, DMNUtils.getRootType(aliasType));
    Type notBuiltInType = new AliasFEELType("notBuiltIn", BuiltInType.UNKNOWN);
    SimpleTypeImpl notBuiltIn = new SimpleTypeImpl(null, "tSimple", null, false, Collections.emptyList(), null, notBuiltInType);
    assertEquals(notBuiltInType, DMNUtils.getRootType(notBuiltIn));
}