Add DB_URL="" to default phpunit.xml to prevent tests running against production/staging

[fil-donadoni]

Problem

The default phpunit.xml in laravel/laravel overrides DB_CONNECTION, DB_DATABASE, and other DB_* variables to ensure tests run against a local/in-memory database. However, it does not override DB_URL.

When DB_URL is set in .env (common for staging/production environments using connection strings), Laravel's database config prioritizes DB_URL over individual DB_* parameters. This means PHPUnit silently ignores all the DB_* overrides in phpunit.xml and connects to the staging/production database instead.

Impact

This can lead to:

• RefreshDatabase running migrations and truncating tables on staging/production
• Silent data corruption — tests pass normally, but against the wrong database
• Hard to diagnose — no warnings are shown; the only clues are unexpected latency or corrupted data

Proposed Fix

Add <env name="DB_URL" value=""/> to the default phpunit.xml in laravel/laravel:

<php>
    <env name="APP_ENV" value="testing"/>
    <!-- ... -->
    <env name="DB_CONNECTION" value="sqlite"/>
    <env name="DB_DATABASE" value=":memory:"/>
    <env name="DB_URL" value=""/>
    <!-- ... -->
</php>

Setting DB_URL to an empty string neutralizes any value from .env, ensuring Laravel falls back to the individual DB_* parameters defined in phpunit.xml.

Steps to Reproduce

1. Fresh Laravel install
2. Set DB_URL=postgresql://user:pass@staging-host:5432/myapp in .env
3. Run php artisan test
4. Tests run against the staging database instead of SQLite in-memory

[github-actions]

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