#includeSource

• Type: string[]
• Default: []

In-source testing is where the test code lives within the same file as the source code, similar to Rust's module tests.

You can define a list of glob patterns that match your in-source test files via includeSource configuration.

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

export default defineConfig({
  includeSource: ['src/**/*.{js,ts}'],
});

#Writing in-source tests

When includeSource defined, Rstest will run all matched files with import.meta.rstest inside.

You can get the Rstest test API via import.meta.rstest.

export const sayHi = () => 'hi';

if (import.meta.rstest) {
  const { it, expect } = import.meta.rstest;
  it('should test source code correctly', () => {
    expect(sayHi()).toBe('hi');
  });
}

#For production

Put the test code inside the if (import.meta.rstest) block, and define import.meta.rstest as false in your build configuration (e.g., rsbuild.config.ts), which will help the bundler eliminate dead code.

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

export default defineConfig({
  source: {
    define: {
+      'import.meta.rstest': false,
    },
  },
});

#TypeScript

To get TypeScript support for import.meta.rstest, you can create a src/rstestEnv.d.ts file to reference:

/// <reference types="@rstest/core/importMeta" />