public Ligature(String successor, String ligature)
    {
        this.successor = successor;
        this.liga = ligature;
    }
@Test
    void testLigature()
    {
        Ligature ligature = new Ligature("successor", "ligature");
        assertEquals("successor", ligature.getSuccessor());
        assertEquals("ligature", ligature.getLigature());
    }