@Test public void testNotSetFragmentedVocabulary() throws Exception {
        IntervalSet vocabulary = IntervalSet.of(1,255);
        vocabulary.add(1000,2000);
        vocabulary.add(9999);
        IntervalSet s = IntervalSet.of(50, 60);
        s.add(3);
        s.add(250,300);
        s.add(10000); // this is outside range of vocab and should be ignored
        String expecting = "{1..2, 4..49, 61..249, 1000..2000, 9999}";
        String result = (s.complement(vocabulary)).toString();
        assertEquals(expecting, result);
    }
Public default constructor used by TestRig
tool-testsuite/test/org/antlr/v4/test/tool/TestIntervalSet.java