* @param refreshToken The refresh token to use for token acquisition.
     * @return The authentication result containing the access token.
     */
    public IAuthenticationResult getAccessToken(final String refreshToken) {
        final String authority = getAuthority() + getTenant() + "/";
        if (logger.isDebugEnabled()) {

        assertEquals("********", SystemUtil.maskSensitiveValue("access_token", "ya29.a0ARrdaM8"));
        assertEquals("********", SystemUtil.maskSensitiveValue("REFRESH_TOKEN", "1//0eXyz"));
    }

    @Test
    public void test_maskSensitiveValue_withCredential() {
        assertEquals("********", SystemUtil.maskSensitiveValue("GOOGLE_CREDENTIALS", "{}"));