Add unit test for integrity

[njzjz]

PR Checklist

• The commit message follows guidelines for NexT.
• The changes have been tested (for bug fixes / features).
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Improvement.
• Code style update (formatting, linting).
• Refactoring (no functional changes).
• Documentation.
• Translation.
• Other... Please describe: unit test

What is the current behavior?

The test is expected to fail due to #728.

What is the new behavior?

• Link to demo site with this changes:
• Screenshots with this changes:

How to use?

In NexT _config.yml:

[njzjz]

It fails as expected due to #728, and should be fixed by #727.

[stevenjoezhang]

Thank you, I have implemented a more strict integrity check in the @next-theme/plugins repository (next-theme/plugins@6683aae), and I believe it will resolve this issue. I will close this pull request.