@Test
public void getQualifiedKey() {

    ObjectValue root = PropertyValue.createObject("a");
    assertThat("a").isEqualTo(root.getQualifiedKey());
    ObjectValue child = PropertyValue.createObject("b");
    ObjectValue n = root.setPropertyValue(child);
    assertThat("a.b").isEqualTo(child.getQualifiedKey());
    child.setValue("c", null);
    PropertyValue val = child.getPropertyValue("c");
    assertThat("a.b.c").isEqualTo(val.getQualifiedKey());
}