feat(core): support custom test environments

[9aoy]

Summary

This PR adds config-level custom test environment support to @rstest/core, so projects are no longer limited to the built-in node, jsdom, and happy-dom environments. It allows loading environment objects from local JavaScript files or rstest-environment-* packages, exports builtinEnvironments and TestEnvironment types for user extension, clarifies when to use custom environments versus setupFiles, and adds unit and e2e coverage for builtin wrappers, named exports, and package fallback resolution.

import { builtinEnvironments } from '@rstest/core';

/** @type {import('@rstest/core').TestEnvironment<typeof globalThis, { marker: string }>} */
const environment = {
  name: 'custom-jsdom',
  async setup(global, options) {
    const base = await builtinEnvironments.jsdom.setup(global, {
      url: 'https://example.com',
    });

    global.__MARKER__ = options.marker;

    return {
      async teardown() {
        delete global.__MARKER__;
        await base.teardown();
      },
    };
  },
};

export default environment;

import { defineConfig } from '@rstest/core';

export default defineConfig({
  testEnvironment: {
    name: './my-environment.mjs',
    options: {
      marker: 'custom-marker',
    },
  },
});

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 44254466e1

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[github-actions]

Rsdoctor Bundle Diff Analysis

Found 12 projects in monorepo, 1 project with changes.

📊 Quick Summary

Project	Total Size	Change
adapter-rsbuild	3.7 KB	0
adapter-rslib	24.7 KB	0
adapter-rspack	7.8 KB	0
browser	2.0 MB	0
browser-react	3.7 KB	0
browser-ui	810.6 KB	0
coverage-istanbul	9.6 KB	0
core/browser	970.1 KB	0
core/loaders	869.0 B	0
core/main	1.7 MB	+2.5 KB (0.1%)
vscode/extension	26.9 MB	0
vscode/worker	14.4 KB	0

📋 Detailed Reports (Click to expand)

📁 core/main

Path: packages/core/.rsdoctor/main/rsdoctor-data.json

📌 Baseline Commit: 7938535556 | PR: #1286

Metric	Current	Baseline	Change
📊 Total Size	1.7 MB	1.7 MB	+2.5 KB (0.1%)
📄 JavaScript	1.6 MB	1.6 MB	+2.5 KB (0.2%)
🎨 CSS	0 B	0 B	0
🌐 HTML	0 B	0 B	0
📁 Other Assets	81.6 KB	81.6 KB	0

📦 Download Diff Report: core/main Bundle Diff

Generated by Rsdoctor GitHub Action

[cloudflare-workers-and-pages]

Deploying rstest with    Cloudflare Pages

Latest commit:	1fa7ba8
Status:	✅  Deploy successful!
Preview URL:	https://01f64faf.rstest.pages.dev
Branch Preview URL:	https://feat-custom-test-environment.rstest.pages.dev

View logs

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 1fa7ba855e

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: d76a0cdf02

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".