@Test( expected = EnforcerRuleException.class )
public void shouldFailWithMissingParentsInReactory()
    throws EnforcerRuleException, ExpressionEvaluationException
{

    MavenProject mp1 = createProjectParent();
    MavenProject mp2 = createProjectChild1( mp1 );
    MavenProject mp3 = createProjectChild2( null );
    List<MavenProject> theList = Arrays.asList( mp1, mp2, mp3 );
    setupSortedProjects( theList );
    rule.execute( helper );
    // intentionally only assertTrue cause we don't expect an exception.
    assertTrue( true );
}