@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);
}