public static String substVars(String val, PropertyContainer pc1) throws ScanException {
        return substVars(val, pc1, null);
    }
@Test
    public void trailingColon_LOGBACK_1140() throws ScanException {
        String prefix = "c:";
        String suffix = "/tmp";
        context.putProperty("var", prefix);
        String r = OptionHelper.substVars("${var}" + suffix, context);
        assertEquals(prefix + suffix, r);
    }