    @Test(groups = TCKConstants.TEST_GROUP_UTILS, expectedExceptions = {InvalidJwtException.class},

        description = "Illustrate validation of signer")
    public void testFailSignature() throws Exception {
        Set<TokenUtils.InvalidClaims> invalidFields = new HashSet<>();
        invalidFields.add(TokenUtils.InvalidClaims.SIGNER);
        String token = TokenUtils.signClaims("/Token1.json", SignatureAlgorithm.RS256, invalidFields);
        validateToken(token);
    }