PHPUnit tests fail: routes.php generated under build/ but tests bootstrap from src/

[avatarf]

When running WordPress core PHPUnit tests via phpunit-test-runner, tests fail with a fatal error because a generated build artifact is expected under src/, but is actually created under build/.

Specifically, PHPUnit bootstraps WordPress from src/, which requires:

src/wp-includes/build/routes.php`

However, after a successful prepare.php, this file is generated at:

build/wp-includes/build/routes.php

As a result, running test.php fails even though prepare.php exits successfully.

Error output

PHP Warning:  require(/tmp/wp-test-runner/src/wp-includes/build/routes.php):
Failed to open stream: No such file or directory in wp-settings.php

PHP Fatal error:  Uncaught Error: Failed opening required
'/tmp/wp-test-runner/src/wp-includes/build/routes.php'

What works / what doesn’t

• php prepare.php
  ✅ completes successfully
  ✅ build artifacts are generated under build/

• php test.php
  ❌ fails because tests bootstrap from src/, where routes.php does not exist

Verified details

• routes.php does exist after prepare:

build/wp-includes/build/routes.php

• vendor/ (PHPUnit) lives in the repo root, so pointing tests directly at build/ breaks PHPUnit execution.

• The runner enforces WPT_TEST_DIR == WPT_PREPARE_DIR in local mode, which makes it impossible to cleanly switch to build/ for tests only.

Environment

• Runner: WordPress/phpunit-test-runner
• WordPress source: wordpress-develop (default clone)
• PHP: 8.2.x
• Node: 20.x
• OS: Ubuntu 24.04 (LXD container)

[kittenkamala]

Thank you so much for reporting this! Related to: #293 .. Going to make this a sub-issue of that for data gathering and continued follow up.

[kittenkamala]

Just want to add that this info you provided has been very helpful in assessing the issue!

[avatarf]

Thanks @kittenkamala for investigating this. Let me know if more logs, environment details, or testing would be helpful.

[kittenkamala]

Thank you too for all your help with this! Issue was resolved in Core. Please comment again if the issue persists!