> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# Rslint

[Rslint](https://rslint.rs/) is an ESLint-compatible linter for JavaScript and TypeScript. Its built-in `rstestPlugin` adds rules for common mistakes in Rstest test definitions, assertions, mocks, and snapshots.

Install [@rslint/core](https://github.com/web-infra-dev/rslint) in your project, then enable the recommended preset in `rslint.config.ts`:


```sh [npm]
npm add @rslint/core -D
```

```sh [yarn]
yarn add @rslint/core -D
```

```sh [pnpm]
pnpm add @rslint/core -D
```

```sh [bun]
bun add @rslint/core -D
```

```sh [deno]
deno add npm:@rslint/core -D
```

## Dedicated test files

If your tests use filenames such as `*.test.ts` or `*.spec.ts`, scope the preset to test and spec files:

```ts title="rslint.config.ts"
import { defineConfig, rstestPlugin } from '@rslint/core';

export default defineConfig([
  {
    ...rstestPlugin.configs.recommended,
    files: ['**/*.{test,spec}.{js,jsx,ts,tsx,cjs,cts,mjs,mts}'],
  },
]);
```

This pattern covers JavaScript and TypeScript files with `.js`, `.jsx`, `.ts`, `.tsx`, `.cjs`, `.cts`, `.mjs`, and `.mts` extensions. The recommended preset does not declare a `files` pattern, so adding one keeps Rstest-specific rules focused on test files and leaves production files to your other Rslint configuration items.

## In-source tests

With [in-source testing](/config/test/include-source.md), tests live alongside production code and use `import.meta.rstest`. Apply the preset to every linted file so it can check both in-source tests and dedicated test files:

```ts title="rslint.config.ts"
import { defineConfig, rstestPlugin } from '@rslint/core';

export default defineConfig([rstestPlugin.configs.recommended]);
```

No additional Rslint globals are required for `import.meta.rstest`.

## Run Rslint

Run Rslint from your project root:


```sh [npm]
npm exec rslint
```

```sh [yarn]
yarn exec rslint
```

```sh [pnpm]
pnpm exec rslint
```

```sh [bun]
bun exec rslint
```

```sh [deno]
deno exec npm:rslint
```

A successful run prints a summary similar to this:

```text
start   Linting...
success Lint passed in 92ms (1 file, 14 rules, 14 threads)
```

When Rslint finds a problem, it reports the rule name, source location, code frame, and failure summary:

```text
start   Linting...

  rstest/no-identical-title  — [error] Test title is used multiple times in the same describe block
  ╭─┴──────────( invalid.test.ts:8:8 )─────
  │ 7 │
  │ 8 │  test('same title', () => {
  │ 9 │    expect(false).toBeFalsy();
  ╰────────────────────────────────

error   Lint failed with 1 error in 31ms (1 file, 14 rules, 14 threads)
```

You can also add the command to the `scripts` section of `package.json` and run it through your package manager's lint script.

## Explore the rules

The [Rslint `rstestPlugin` preset](https://rslint.rs/api/presets/rstest-plugin) documents the available configuration and usage patterns. To see which rules are included in the recommended preset, open the [Rstest rules list](https://rslint.rs/rules/?preset=rstestPlugin.configs.recommended).