#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}'],
});

includeSource works in both Node mode and browser mode projects.

#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. When generating non-test output, define import.meta.rstest as false in your project's build configuration so the bundler can eliminate the test code as dead code.

• Use Rspack's DefinePlugin:

import { defineConfig } from '@rspack/cli';
+import { rspack } from '@rspack/core';

export default defineConfig({
+  plugins: [
+    new rspack.DefinePlugin({
+      'import.meta.rstest': false,
+    }),
+  ],
});

• Use Rsbuild's source.define option:

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

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

#TypeScript

To get TypeScript support for import.meta.rstest, we recommend adding @rstest/core/importMeta to compilerOptions.types in the tsconfig.json for your test files:

{
  "compilerOptions": {
    "types": ["@rstest/core/importMeta"]
  }
}

If your tsconfig.json already configures compilerOptions.types, append this type to the existing list.

Alternatively, reference the type in src/rstestEnv.d.ts:

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