Fix test failures due to WP 6.4 change

[felixarntz]

Summary

As of the WordPress 6.4 release, our unit tests are failing. This hasn't happened yet in trunk, but only because no PRs have been opened since the release. It is however obvious in https://github.com/WordPress/performance/actions/runs/6851370708/job/18627496026?pr=864.

The failures happen simply because of deprecation warnings for print_emoji_styles() which per core behavior remains added as a callback for the wp_print_styles action but normally gets removed via another core function before it would be executed. In certain custom situations though (such as tests), it may be necessary to manually remove it. Even core itself does that for example in https://github.com/WordPress/wordpress-develop/blob/d66ef46847e2340c613d0a01c36d4fcc4b5f3a6b/src/wp-includes/block-editor.php#L363.

Checklist

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[swissspidy]

I feel like we should reconsider the approach with how this function is handled in core. I don't see why the function still needs to be hooked into wp_print_styles just so everyone has to unhook it again. That seems like worse DX than just unhooking it by default.

See also https://core.trac.wordpress.org/ticket/59892

[felixarntz]

@swissspidy

I feel like we should reconsider the approach with how this function is handled in core. I don't see why the function still needs to be hooked into wp_print_styles just so everyone has to unhook it again. That seems like worse DX than just unhooking it by default.

This was done for backward compatibility with existing code. It's a clunky DX, but it's a tradeoff between breaking BC and clunky DX. I don't feel strongly either way. cc @westonruter

I've addressed your code feedback in a3bc55d.

[westonruter]

What is this about:

Warning: file_put_contents(/var/www/html/wp-content/plugins/performance/.phpunit.result.cache): failed to open stream: Permission denied in phar:///usr/local/bin/phpunit/phpunit/Runner/DefaultTestResultCache.php on line 111

[swissspidy]

This was done for backward compatibility with existing code.

Yes I saw that in the code comments, but I wonder if it actually addresses a real backward compatibility issue.