Travis/QA: always check that all sniffs are feature complete

[jrfnl]

The new phpcsstandards/phpcsdevtools package includes a script which can check whether sniffs are feature complete, i.e. whether all sniffs have unit tests and documentation.

By adding this check to the Travis script, we prevent untested and/or undocumented sniffs from entering the repo.

Ref: https://github.com/PHPCSStandards/PHPCSDevTools#checking-whether-all-sniffs-in-a-phpcs-standard-are-feature-complete

P.S.: the PHPCSDevTools package contains a few more goodies, have a look at the readme for more information.

[hansjovis]

Code Review: 👍

This is actually very meta: sniffs for checking sniffs 😄.

[hansjovis]

Acceptance test: ✅

• The Travis build passes and the check-complete composer command is executed.
• Running the check-complete composer command locally works as well.
  • I get 13 results, which is consistent with the number of Yoast sniffs we have.
  • Manually removing a unit test for a Yoast sniff correctly gives an error:
    ERROR: Unit tests missing for /Yoast/Sniffs/Files/FileNameSniff.php.

[jrfnl]

This is actually very meta: sniffs for checking sniffs

It's not actually a sniff, but a simple command-line PHP script. I actually wrote it for PHPCS itself, but set it up so it can also be used by external standards 😉

If we're talking meta:
For WPCS we'll be creating some dev sniffs to be run over WP Core to generate the lists with deprecated functions and such for the user-facing sniffs. 😎
Sniffs are good at retrieving that kind of info and it can help prevent (the user-facing) sniffs from going out-of-date because lists aren't (manually) updated regularly enough.