Tests: Document value comparisons in post tests

[noruzzamans]

Description

Reviewed tests/phpunit/tests/post/ for ticket #64895.

There are 6 calls to assertEquals() across 4 files:

• tests/phpunit/tests/post/getPageByPath.php:
  • Line 41: Comparing $page (WP_Post) with object returned from get_page_by_path( 'some-page' ).
  • Line 44: Comparing $other_att (WP_Post) with object returned from get_page_by_path( 'some-other-page' ).
• tests/phpunit/tests/post/meta.php:
  • Line 174: Comparing $mobj (stdClass) with database row object returned from get_post_meta_by_id( $mid ).
  • Line 181: Comparing $mobj (stdClass) with database row object returned from get_post_meta_by_id( $mid ).
• tests/phpunit/tests/post/types.php:
  • Line 295: Comparing $before labels object (stdClass) with $after labels object after calling get_post_type_labels().
• tests/phpunit/tests/post/wpCountAttachments.php:
  • Line 31: Comparing $expected object with cached object returned from wp_cache_get( $cache_key, 'counts' ).

All 6 calls intentionally compare object instances by value:

1. get_page_by_path() queries the database and instantiates a WP_Post object, which is a separate instance from fixture references in the test.
2. get_post_meta_by_id() constructs a database row object, distinct from the manually constructed $mobj fixture.
3. get_post_type_labels() casts the labels array to a fresh (object), producing a distinct instance from $before.
4. WP_Object_Cache::get() intentionally clones objects upon cache retrieval, returning a distinct instance in memory from $expected.

In accordance with maintainer guidance on Trac #64895 (comments 88 & 93), these intentional loose comparisons are preserved and documented with:
// Keep assertEquals() because the objects are intentionally compared by value.

Testing Instructions

npm run test:php -- tests/phpunit/tests/post/getPageByPath.php tests/phpunit/tests/post/meta.php tests/phpunit/tests/post/types.php tests/phpunit/tests/post/wpCountAttachments.php
npm run test:php -- -c tests/phpunit/multisite.xml tests/phpunit/tests/post/getPageByPath.php tests/phpunit/tests/post/meta.php tests/phpunit/tests/post/types.php tests/phpunit/tests/post/wpCountAttachments.php
composer run lint tests/phpunit/tests/post/getPageByPath.php tests/phpunit/tests/post/meta.php tests/phpunit/tests/post/types.php tests/phpunit/tests/post/wpCountAttachments.php

Trac ticket: https://core.trac.wordpress.org/ticket/64895

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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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Props noruzzaman.

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[lancewillett]

PR #13939 landed in https://core.trac.wordpress.org/changeset/64071