Add feature tests via Behat

[schlessera]

Summary

This PR adds feature testing via Behat to the plugin. It reuses the testing infrastructure and Behat definitions from WP-CLI (see https://github.com/wp-cli/wp-cli-tests).

Before the tests are run for the first time, the following command has to be executed:

composer prepare-tests

This should create the needed table(s) in the database for the tests to be run within.

Database credentials can be provided via environment variables if the database is not found on localhost:3306:

• WP_CLI_TEST_DBHOST is the host to use and can include a port, i.e 127.0.0.1:33060 (defaults to localhost)
• WP_CLI_TEST_DBROOTUSER is the user that has permission to administer databases and users (defaults to root).
• WP_CLI_TEST_DBROOTPASS is the password to use for the above user (defaults to an empty password).
• WP_CLI_TEST_DBUSER is the user that the tests run under (defaults to wp_cli_test).
• WP_CLI_TEST_DBPASS is the password to use for the above user (defaults to password1).

Then, to run the tests, the following command can be used:

vendor/bin/behat

Note: The code coverage is currently not being executed on GHA because there is still an issue with the interpretation of the code coverage data within codecov (probably a path discrepancy). This should be fixed and re-enabled in a separate PR.

Fixes #3076

Checklist

• My code is tested and passes existing tests.
• My code follows the Engineering Guidelines (updates are often made to the guidelines, check it out periodically).

[codecov]

Codecov Report

Merging #6070 (17d8501) into develop (8d1425e) will decrease coverage by 3.83%.
The diff coverage is 0.00%.

❗ Current head 17d8501 differs from pull request most recent head 07a844f. Consider uploading reports for the commit 07a844f to get more accurate results

@@              Coverage Diff              @@
##             develop    #6070      +/-   ##
=============================================
- Coverage      75.03%   71.20%   -3.84%     
+ Complexity      5829     5827       -2     
=============================================
  Files            232      233       +1     
  Lines          17618    18566     +948     
=============================================
  Hits           13219    13219              
- Misses          4399     5347     +948     

Flag	Coverage Δ	Complexity Δ
feature	0.00% <0.00%> (?)	0.00 <0.00> (?)
javascript	79.84% <ø> (ø)	0.00 <ø> (ø)
php	70.83% <0.00%> (-3.99%)	5827.00 <0.00> (-2.00)
unit	74.78% <0.00%> (?)	5827.00 <0.00> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ	Complexity Δ
includes/bootstrap.php	0.00% <0.00%> (ø)	0.00 <0.00> (?)
src/Cli/TransformerCommand.php	0.00% <ø> (ø)	29.00 <0.00> (-2.00)
src/Admin/PluginActivationNotice.php	59.09% <0.00%> (-40.91%)	7.00% <0.00%> (ø%)
...cludes/embeds/class-amp-playlist-embed-handler.php	77.06% <0.00%> (-18.40%)	35.00% <0.00%> (ø%)
src/AmpWpPlugin.php	85.18% <0.00%> (-14.82%)	9.00% <0.00%> (ø%)
src/DevTools/CallbackReflection.php	85.00% <0.00%> (-12.15%)	17.00% <0.00%> (ø%)
...s/sanitizers/class-amp-accessibility-sanitizer.php	70.58% <0.00%> (-9.42%)	6.00% <0.00%> (ø%)
src/Admin/PluginRowMeta.php	90.90% <0.00%> (-9.10%)	4.00% <0.00%> (ø%)
src/DevTools/LikelyCulpritDetector.php	90.90% <0.00%> (-9.10%)	10.00% <0.00%> (ø%)
includes/sanitizers/class-amp-img-sanitizer.php	88.77% <0.00%> (-8.88%)	87.00% <0.00%> (ø%)
... and 91 more

[github-actions]

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[westonruter]

I tried running composer prepare-tests but I got:

> install-package-tests
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
Detected MySQL at version .
/app/public/content/plugins/amp/vendor/bin/install-package-tests: 75: [: Illegal number:
+ mysql -e CREATE DATABASE IF NOT EXISTS `wp_cli_test`; -uroot
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
Script install-package-tests handling the prepare-tests event returned with error code 1

[westonruter]

I guess that's because my environment variables are empty.

[westonruter]

Tests are working in CI context, so that's the most important thing.