Add general rule tests

[sindresorhus]

Like: https://github.com/sindresorhus/eslint-plugin-unicorn/blob/master/test/package.js Can probably just borrow those directly.

[rahgurung]

@sindresorhus assertion-message is deprecated but why the rule is still there? We need to add back the docs and tests to make the tests pass. Another problem i faced is no-ignored-test-files is rule which have two tests in different files like no-ignored-test-files-with-package and no-ignored-test-files-without-package, I should merge them ?

[sindresorhus]

assertion-message is deprecated but why the rule is still there?

Graceful removal. We can remove it now though.

Another problem i faced is no-ignored-test-files is rule which have two tests in different files like no-ignored-test-files-with-package and no-ignored-test-files-without-package, I should merge them ?

I would just add a manual ignore check for those.

[sindresorhus]

Graceful removal. We can remove it now though.

Removed