[shail-mehta]

Trac ticket: #65819

What

Adds a dedicated PHPUnit class for rest_output_link_header(), covering empty body output, the empty REST URL early return, and the REST API Link header when xdebug is available.

Test-only; no production code changes.

Why

rest_output_link_header() had no direct @covers coverage. Small helper coverage fits the #65819 test cleanup track.

How

Add tests/phpunit/tests/rest-api/restOutputLinkHeader.php with @covers ::rest_output_link_header.

• Writes nothing to the response body
• Outputs nothing when rest_url is filtered to an empty string
• Sends the https://api.w.org/ Link header (@requires function xdebug_get_headers)

Testing Instructions

1. npm run test:php -- --filter Tests_REST_API_RestOutputLinkHeader
2. npm run test:php -- --filter Tests_REST_API_RestOutputLinkHeader -c tests/phpunit/multisite.xml
3. npm run test:php -- --filter Tests_REST_API_RestOutputLinkHeader --order-by=random
4. npm run test:php -- --group restapi

Use of AI Tools

• Cursor

[Copilot]

🟡 Changes recommended

The tests lack process isolation, causing bootstrap output to bypass the intended code paths, and the empty-URL test does not assert that headers remain unchanged.

2 open issues

• Isolate header tests from bootstrap output · New
• Assert empty URLs do not add a Link header · New

What changed in this PR

Adds dedicated PHPUnit coverage for rest_output_link_header() as part of the REST API test cleanup in Trac #65819. No production code changes.

Changes:

• Adds a test class with explicit @covers metadata.
• Checks response-body output with normal and empty REST URLs.
• Adds an Xdebug-dependent assertion for the REST API Link header.

File	Description
tests/​phpunit/​tests/​rest-api/​restOutputLinkHeader.php	Adds three tests for REST API link-header behavior.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues were reported for the test-only addition of direct PHPUnit coverage for rest_output_link_header().

No open issues 🎉

2 resolved since last review

• Isolate header tests from bootstrap output
• Assert empty URLs do not add a Link header

_{Review effort: Balanced}

[github-actions]

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[lancewillett]

The actual HTTP-header assertions passed locally with Xdebug enabled, in both single-site and multisite randomized runs. All three new methods executed with zero skips; PHPCS passed. The separate-process setup follows the existing header tests.

_{AI review · gpt-6}

[lancewillett]

PR #15284 landed in https://core.trac.wordpress.org/changeset/65140