some vibe tests

better than none

README.md

@@ -75,6 +75,29 @@ needed just to run the application.
 just test
 ```
 
+`just test` starts a separate MySQL 5.7 service (`db-test`) and runs PHPUnit in
+the PHP container. The `pollux_test` database uses temporary storage, has no
+published port, and is separate from the development database and its volume.
+Tests migrate this database automatically and roll back their fixtures after
+each test. No demo or real-data seeders are needed. Run `just setup` first on a
+new checkout to build the PHP image and install dependencies.
+
+To run a focused subset:
+
+```sh
+just test --filter BookingsTest
+```
+
+Coverage includes login/logout and guest access, booking forms and changes,
+split entries, validation, deletion cascades, income/expense totals, monthly
+balances, year boundaries, project and scope reports, and target payment states.
+These are PHP HTTP/database tests; they do not exercise browser JavaScript.
+
+PHPUnit forces isolated database settings, and the test bootstrap refuses to run
+against another database configuration. If cached application configuration
+prevents testing, run `just artisan config:clear`. `just down` also stops the test
+database; its temporary data is discarded when the container stops.
+
 ## Legacy compatibility notes
 
 This project uses several old dependencies, so a few small compatibility fixes