[hmbashar]

Adds unit tests for render_block_core_post_comments_form(), post_comments_form_block_form_defaults() and register_block_core_post_comments_form() in src/wp-includes/blocks/post-comments-form.php, which were not referenced by any test. No behavior is changed.

The new test class tests/phpunit/tests/blocks/renderPostCommentsForm.php (15 tests) covers:

• Nothing is rendered without a postId or when the comments are closed, and the function returns null for a post that needs a password.
• The comment form of the post inside the wrapper of the form (id="respond" and comment-respond), with the has-text-align-* and has-link-color classes of the block.
• The script comment-reply is enqueued only when the form is rendered, and the filter of the defaults of the form is removed afterwards.
• post_comments_form_block_form_defaults() leaves the defaults as they are for a theme that is not a block theme, and changes the submit button and the submit field for a block theme (also in the rendered form).
• The block is registered with the render callback.

Testing:

• vendor/bin/phpunit --filter 'Tests_Blocks_RenderPostCommentsForm::'
• vendor/bin/phpunit -c tests/phpunit/multisite.xml --filter 'Tests_Blocks_RenderPostCommentsForm::'
• vendor/bin/phpcs tests/phpunit/tests/blocks/renderPostCommentsForm.php

I also temporarily broke the functions (each check, the classes, the filter that is removed, the post of the form, the replacement of the wrapper, the script, the check of the block theme, and the markup of the button and the field) and confirmed that a new test fails for each one. The add_filter() call of the defaults is not caught, because comment_form() already applies the same defaults for a block theme.

Trac ticket: https://core.trac.wordpress.org/ticket/66541

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Sonnet 5.5
Used for: Written with AI and manually reviewed by me.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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Core Committers: Use this line as a base for the props when committing in SVN:

Props hmbashar, huzaifaalmesbah.

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[huzaifaalmesbah]

Thanks for working on this, @hmbashar! I really appreciate you taking the time to cover the server-side rendering of the Post Comments Form block (render_block_core_post_comments_form(), post_comments_form_block_form_defaults(), and block registration). Local PHPUnit suite (15 tests, 24 assertions) and PHPCS/ESLint both pass cleanly.

I left a couple of small notes inline.

_{AI Review: Gemini 3.8 Flash}

[Copilot]

🟡 Changes recommended

The tests leak script and block-registry state into subsequent tests, and an integration assertion cannot detect a missing defaults-filter hookup.

3 open issues

• Restore the global script registry after each test · New
• Restore the original block type after the test · New
• Assert submit classes to verify the defaults filter hookup · New

What changed in this PR

Adds unit coverage for server-side rendering of the Post Comments Form block and its helper functions, addressing Trac ticket #66541 without changing production behavior.

Changes:

• Tests rendering conditions, wrapper classes, and the associated post.
• Checks script enqueueing, filter cleanup, and classic- versus block-theme form defaults.
• Verifies block registration and its render callback.

File	Description
tests/​phpunit/​tests/​blocks/​renderPostCommentsForm.php	Adds tests for rendering, form defaults, side effects, and block registration.

_{Review effort: Balanced}