@Test public void testRangeAndIsolatedElement() throws Exception {
        IntervalSet s = IntervalSet.of('a','z');
        IntervalSet s2 = IntervalSet.of('d');
        String expecting = "100";
        String result = (s.and(s2)).toString();
        assertEquals(expecting, result);
    }
Public default constructor used by TestRig
tool-testsuite/test/org/antlr/v4/test/tool/TestIntervalSet.java