@module-federation/rstest

Module Federation integration for Rstest Node, JSDOM, and browser test environments.

Installation

npm install --save-dev @module-federation/rstest @rstest/core

Use @rstest/[email protected] or newer. That release includes Rstest's federation support (web-infra-dev/rstest#1407).

Usage

Node and JSDOM

import { federation } from '@module-federation/rstest';
import { defineConfig } from '@rstest/core';

export default defineConfig({
  plugins: [
    federation({
      name: 'main_app_web',
      remotes: {
        'component-app': 'component_app@http://localhost:3001/remoteEntry.js',
      },
      shared: {
        react: { singleton: true },
        'react-dom': { singleton: true },
      },
    }),
  ],
});

For Node test environments, the plugin enables Rstest's federation compatibility mode automatically. Do not also set federation: true in rstest.config.*.

If the test project already uses @module-federation/rsbuild-plugin, reuse that configuration instead of declaring the options twice:

import { createModuleFederationConfig, pluginModuleFederation } from '@module-federation/rsbuild-plugin';
import { federation } from '@module-federation/rstest';
import { defineConfig } from '@rstest/core';

const options = createModuleFederationConfig({
  name: 'main_app_web',
  remotes: {
    'component-app': 'component_app@http://localhost:3001/remoteEntry.js',
  },
});

export default defineConfig({
  plugins: [
    pluginModuleFederation(options, {
      environment: 'rstest',
      target: 'node',
    }),
    federation(),
  ],
});

Register the Rsbuild plugin first. federation() then applies the Rstest defaults to the same typed options and creates a single compiler plugin.

For both Node and browser targets, dts, manifest, and dev default to false; explicit values are preserved.

The plugin applies these Node defaults:

• target: async-node
• experiments.asyncStartup = true
• CommonJS library output (library.type = 'commonjs-module'); module and modern-module library types are normalized
• Node runtime plugin (@module-federation/node/runtimePlugin)
• experiments.optimization.target = 'node'
• Script remote transport (remoteType = 'script'); inline prefixes such as commonjs ... still override the default

Browser Mode

Install @rstest/browser and a Playwright browser before enabling Browser Mode. See Rstest's Browser Mode setup.

import { federation } from '@module-federation/rstest';
import { defineConfig } from '@rstest/core';

export default defineConfig({
  browser: {
    enabled: true,
    provider: 'playwright',
  },
  plugins: [
    federation({
      name: 'browser_host',
      remotes: {
        app2: 'app2@http://localhost:3001/remoteEntry.js',
      },
    }),
  ],
});

Browser Mode is detected from Rstest's resolved browser.enabled configuration. In browser target mode, node-only defaults are not applied. experiments.asyncStartup remains enabled.

The plugin name is rstest:federation, exported as FEDERATION_PLUGIN_NAME.

Real-world Example

Rstest's federation example tests an HTTP component remote and a locally built CommonJS remote from Node and JSDOM projects. It covers both static and dynamic remote imports.

Documentation

See the Rstest integration guide for configuration details.