[Tracking]: Test-Related Package Consolidation

[valentinpalkovic]

This milestone aims to consolidate test-related packages into a unified @storybook/addon-test package. The goal is to simplify testing workflows and ensure all relevant test utilities are maintained under a single addon. The work requires package migrations, updates to CLI behavior, automigrations, and comprehensive documentation.

Items:

1. Promote @storybook/experimental-addon-test to stable @storybook/addon-test

• Rename and restructure @storybook/experimental-addon-test as @storybook/addon-test
  • Update package.json metadata (name, version, description) in the package
  • Remove "experimental" labels and update all internal references in the codebase
  • Automigration

2. Merge test-related packages into core

• Merge @storybook/addon-interactions
  • Make sure automigrations or init scripts don't install @storybook/addon-interactions anymore
• Merge @storybook/instrumenter
  • Transfer instrumentation logic from @storybook/instrumenter into core
  • Update all related import paths and documentation in the codebase to use storybook/test for instrumentation
• Merge @storybook/test
  • Automigration
  • Rewrite eslint plugin to not require @storybook/test
• Merge @storybook/addon-actions
  • Move the implementation actions addon into core
  • Test https://storybook.js.org/docs/essentials/actions#action-event-handlers separately

3. Update CLI to reflect new Test addon behavior

• Modify the Storybook CLI to include @storybook/addon-test when "Testing" is selected for all Vite-based Storybook projects
  • Make sure that template stories use storybook/test

4. Automigration & Documentation Updates

• Write an automigration script to transition existing projects to the new addon addon-test
• Automatically replace old imports (@storybook/test, @storybook/addon-actions, etc.) with storybook/test in user codebases
• Update Addon Kit to use storybook/test
• Provide a clear migration guide
• Point @storybook/addon-test readme to official documentation
• Remap https://github.com/storybookjs/storybook/blob/next/code/addons/test/src/vitest-plugin/index.ts#L298

5. Deprecate packages on npm

• Deprecate @storybook/test, @storybook/instrumenter, @storybook/addon-actions and @storybook/addon-interactions on npm

6. Release satellite packages

• vite-plugin-storybook-nextjs

Nice to have:

• Take a look at https://github.com/storybookjs/storybook/blob/next/code/core/src/preview-api/modules/store/csf/prepareStory.ts#L58-L60 workaround. Can be removed