Handbook: Modernize the plugin's PHPUnit test suite.

[obenland]

The handbook tests extended WP_UnitTestCase, whose set_up() calls PHPUnit\Util\Test::parseTestMethodAnnotations() — removed in PHPUnit 10. WordPress has no PHPUnit 10+ compatible test case, so every test errored before reaching an assertion.

They now extend a small local base test case that provides only the three helpers the suite actually uses (factory(), go_to(), assertQueryTrue()) plus the per-test isolation those depend on. Test bodies are unchanged.

Changes

• Adds a wp-env test environment for the plugin, matching the ones the plugin and theme directories already use, and points the existing CI matrix entry at it. It previously had no config and relied on plugin auto-detection.
• Renames the test files to match their class names, which PHPUnit now requires for directory-based discovery.
• Replaces four assertions that hardcoded http://example.org/… with home_url(), so they no longer depend on the test suite's default domain.
• Converts @dataProvider annotations to #[DataProvider] attributes, which PHPUnit 12 will require.
• Varies the page navigation cache key by whether the current user can read private posts, so a cached page list is only reused for viewers it was built for, with tests covering both orderings.
• Fixes a PHP 8.4 deprecation surfaced by the now-running suite: parse_url() returns null for a home URL with no path, which trim() no longer accepts.

Test-isolation fixes

Running the suite in randomized order surfaced two pre-existing order dependencies, both of which WP_UnitTestCase never guarded against either:

• WPorg_Handbook_Admin_Notices_Test had no setUp(), so it only passed when it ran before any class whose tearDown() calls WPorg_Handbook_Init::reset().
• test_filter_wporg_handbook_sidebar_args() overwrote the $wp_registered_sidebars global without restoring it.

Verification

140 tests, 227 assertions, no failures or deprecations on PHPUnit 11.5 / PHP 8.4, stable across repeated randomized ordering. Run locally with:

cd environments && npm run handbook:test

🤖 Generated with Claude Code

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