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Checking and Testing

You should make sure your changes are properly checked and tested. Most of the time, this means you should at least manually tested the change, and if needed, add at least one Snapshot Test if the runtime is changed.

Checking

Running task check in the root of the repo will run a handful of checks and lints. You can also run task exec -- XXX:check to only run checks for one package.

When there are formatting issues, task exec -- XXX:fix can automatically fix that.

Unit and Manual Tests

We use Vitest for unit testing TypeScript code and standard Cargo test for Rust. The only difference is since we use mono-dev configurations, import from mono-dev/vitest instead of vitest.

Also make sure to test your changes manually in the app. See Build and Run for how to run the app locally.

Snapshot Tests

Snapshot tests are the most important tests in the project. These tests are simulator scripts that the test tool runs and captures the state at each step, and saves them to a text file in a human readable format. Any diff in the snapshot is considered a failure.

To add a snapshot test, put a .txt file containing the script in /packages/runtime-tests/src/script_tests/, then run task exec -- runtime-tests:run-full (or run-mini). This will generate a new snapshot in snapshots/. Open the file and make sure the state is what you expect at every step.

If a snapshot test fails, the new snapshot will be saved to snapshots/wip. You can diff the snapshot with task diff -- NAME_OF_TEST. (Requires the delta tool). When you think the new snapshot is ready, copy it to snapshots and replace the old snapshot.

You can also run the ust task to update all snapshots.

Warning

The snapshot tests are used to generate the memory trace to build the mini image. If your new tests require changing the mini image, make sure that test pass but do not include it in the Pull Request (since you don’t have access to update the mini image). Instead open a different Pull Request with just the new tests, and I will push a commit that updates the mini image.