    @Test
    public void testSortByGuider() {

        ImList<GuideProbeTargets> lst = DefaultImList.create(fix.gpt_pwfs2, fix.gpt_gmos, fix.gpt_pwfs1);
        lst = GuideProbeTargets.sortByGuider(lst);

        assertSame(fix.gpt_gmos, lst.get(0));
        assertSame(fix.gpt_pwfs1, lst.get(1));
        assertSame(fix.gpt_pwfs2, lst.get(2));

        lst = DefaultImList.create();
        ImList<GuideProbeTargets> lst2 = GuideProbeTargets.sortByGuider(lst);
        assertSame(lst, lst2);

        lst = DefaultImList.create(fix.gpt_gmos);
        lst2 = GuideProbeTargets.sortByGuider(lst);
        assertEquals(lst, lst2);
    }