release-bundle-testing

Release bundle testing

Rozenite is a development tool. Whatever a project wires into its bundler config, a release build must ship none of our code. @rozenite/test-utils provides the bench that proves it, and every plugin owns a Vitest suite in src/__tests__/release-bundle.test.ts that uses it.

These guards belong to plugins. A plugin is what an app installs and what carries a DevTools panel, so it is where a leak would reach a shipped app. Bundler packages (@rozenite/metro, @rozenite/web) are not guarded this way -- they ship no panel, and the behaviour that matters about them is already covered by the plugin guards that wire through withRozenite.

There are two guard shapes; a plugin may need both.

1. Panel guard -- for every plugin an app can import. Bundle an app that requires the plugin's React Native entry and assert panelModules is empty. The plugin's own React Native code is expected in the bundle: an app asked for it. Its DevTools panel never is.
2. Bundler integration guard -- for plugins exporting ./metro. Bundle with the integration applied and assert rozeniteModules is empty.

The bench

bundleForRelease() creates a throwaway app in a temp directory, bundles it through Metro's JavaScript API with dev: false, and reports what ended up inside:

import { bundleForRelease, RELEASE_BUNDLE_TIMEOUT } from '@rozenite/test-utils';
import { withRozenite } from '@rozenite/metro';

it(
  'leaves no Rozenite code in a release bundle when disabled',
  async () => {
    const result = await bundleForRelease({
      projectType: 'expo', // or 'react-native' (default)
      resolveFrom: packageRoot,
      configureMetro: (config) =>
        withRozenite(config, { enabled: false, enhanceMetroConfig: withMyPlugin }),
    });

    expect(result.rozeniteModules).toEqual([]);
  },
  RELEASE_BUNDLE_TIMEOUT,
);

• projectType picks the default config: @react-native/metro-config (React Native CLI) or expo/metro-config.
• configureMetro applies the integration under test. It accepts anything a Metro config transformer returns, including the function withRozenite produces.
• resolveFrom should be the root of the package under test, so its own @rozenite/* dependencies resolve from the fixture.
• files replaces the fixture's sources when a case needs the app to import something.