@Test
public void testHandleAttributeAddition_LockLHS() {

    popup.handleAttributeAddition(RuleAttributeWidget.LOCK_LHS);
    assertThat(model.attributes).isEmpty();
    assertThat(model.metadataList).containsExactly(new RuleMetadata(RuleAttributeWidget.LOCK_LHS, "true"));
    verify(refreshCommand).execute();
}