    @Test
    public void getRTokenExpirationTime() {

        long prev = Long.parseLong(String.valueOf(ReflectionTestUtils.getField(sc, "rTokenExpirationTime")));
        final long expTime = -10;
        ReflectionTestUtils.setField(sc, "rTokenExpirationTime", expTime);
        assertTrue("Expiration time for refresh token must be greater than zero",
                jwtService.getRTokenExpirationTime() > 0);
        // restore value
        ReflectionTestUtils.setField(sc, "rTokenExpirationTime", prev);
    }