@Test public void testSubtractOfOverlappingRangeFromRight() throws Exception {
        IntervalSet s = IntervalSet.of(10,20);
        IntervalSet s2 = IntervalSet.of(15,25);
        String expecting = "{10..14}";
        String result = (s.subtract(s2)).toString();
        assertEquals(expecting, result);

        IntervalSet s3 = IntervalSet.of(20,25);
        expecting = "{10..19}";
        result = (s.subtract(s3)).toString();
        assertEquals(expecting, result);
    }
Public default constructor used by TestRig
tool-testsuite/test/org/antlr/v4/test/tool/TestIntervalSet.java