@Test
    public void indexFromValue() {
        Goo g1 = new Goo(114, "lu-" + 114);
        Goo g2 = new Goo(13, "lu-" + 13);
        Goo g3 = new Goo(600, "lu-" + 600);
        Goo g4 = new Goo(9, "lu-" + 9);
        Goo g5 = new Goo(7, "lu-" + 7);

        objh.insert(114, g1);

        objh.insert(13, g2);
        objh.insert(600, g3);
        objh.insert(9, g4);
        objh.insert(7, g5);

        assertTrue(objh.contains(g1));
        assertTrue(objh.contains(g2));
        assertTrue(objh.contains(g3));
        assertTrue(objh.contains(g4));
        assertTrue(objh.contains(g5));


        assertEquals(7, objh.min().getNum(), 7);
        objh.change_key(g1, 1);
        assertEquals(114, objh.min().getNum(), 114);
        objh.delete_min();
        assertFalse(objh.isEmpty());
        assertEquals(g5, objh.min());
        assertFalse(objh.min().equals(g1));

        while (!objh.isEmpty()) {
            objh.delete_min();
        }

        assertFalse(objh.contains(g1));
        assertFalse(objh.contains(g2));
        assertFalse(objh.contains(g3));
        assertFalse(objh.contains(g4));
        assertFalse(objh.contains(g5));

        assertTrue(objh.isEmpty());
    }