[ISSUE #1665] Add more unit test for Validators

[jamesxuhaozhe]

What is the purpose of the change

Add more unit test for Validators

Brief changelog

XX

Verifying this change

UT passes

Follow this checklist to help us incorporate your contribution quickly and easily. Notice, it would be helpful if you could finish the following 5 checklist(the last one is not necessary)before request the community to review your PR.

• Make sure there is a Github issue filed for the change (usually before you start working on it). Trivial changes like typos do not require a Github issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Format the pull request title like [ISSUE #123] Fix UnknownException when host config not exist. Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test(over 80% coverage) to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add integration-test in test module.
• Run mvn -B clean apache-rat:check findbugs:findbugs checkstyle:checkstyle to make sure basic checks pass. Run mvn clean install -DskipITs to make sure unit-test pass. Run mvn clean test-compile failsafe:integration-test to make sure integration-test pass.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

[coveralls]

Coverage decreased (-0.04%) to 50.6% when pulling e2dffc6 on jamesxuhaozhe:develop into f8f6fbe on apache:develop.

[jamesxuhaozhe]

I'm not sure why some of the checks failed. But doesn't look they failed because of my change. Can someone kindly review this pr? Thanks!

[duhenglucky]

@jamesxuhaozhe the Travis failed because the coverage decreased, you can ignore this temporarily, or add more unit tests to improve coverage.

[jamesxuhaozhe]

@jamesxuhaozhe the Travis failed because the coverage decreased, you can ignore this temporarily, or add more unit tests to improve coverage.

Thank you. However, I am still confused. Because if you take a look at the code change I made in this pr. The change did nothing but adding more unit tests. Ideally, the test coverage should increase a little bit. Let me know how should I fix this and if I am missing anything. Thanks a lot!

[jamesxuhaozhe]

@duhenglucky Not sure what is going on, I added even more unit tests like you suggested, but the coverage still dropped. Much appreciated if you can help to take a look at. Just trying to get this pr to merge. :)

[duhenglucky]

@jamesxuhaozhe Would you like resole conflicts first?