String s3 = props2.getProperty("dblbackslash");
        assertEquals("\\", s3, "13");
        assertEquals(props1, props2);
    }

    @Test
    public void testConfigInterpolation() throws IOException {
        String config = "a=$\\\\\\\\{var}\n" + "ab=${a}b\n" + "abc=${ab}c";
        Map<String, String> expected = Map.of("a", "$\\{var}", "ab", "$\\{var}b", "abc", "$\\{var}bc");