@gabroberge/eslint-plugin-vitest

Nest/Vitest lint rules for how a spec is structured: suite vs scenario, arrange vs act, and what a test is allowed to assert.

The plugin registers as vitestExtended. Enable configs.recommended for the rules that are cheap to enforce automatically. configs.all also turns on the rules that need more judgment.

Install

npm install -D @gabroberge/eslint-plugin-vitest

Usage

ESLint flat config

import vitestExtended from "@gabroberge/eslint-plugin-vitest";

export default [vitestExtended.configs.recommended];

Oxlint

{
	"jsPlugins": ["@gabroberge/eslint-plugin-vitest"],
	"rules": {
		"vitestExtended/require-expect": "error"
	}
}

Configs

| Config | What it enables | | --------------------- | --------------------------------------------------------- | | configs.recommended | Rules marked recommended, at each rule's default severity | | configs.all | Every rule, at each rule's default severity |

Rules

| Rule | Recommended | Fix | Default | What it reports | | ---------------------------------------------------- | ----------- | --- | ------- | ------------------------------------------------------------------------- | | vitestExtended/no-identical-test-body | yes | | error | An it / test body that repeats an earlier test in the same describe | | vitestExtended/no-if-in-test-title | yes | | error | An it / test title that contains if | | vitestExtended/no-single-case-each | yes | | error | .each with exactly one statically known case | | vitestExtended/no-spy-on-outside-before-each | yes | | error | vi.spyOn created outside beforeEach | | vitestExtended/no-tautological-equality | yes | | error | Equality that compares a value with itself or a sole spread of itself | | vitestExtended/no-test-outside-describe | yes | | error | An it / test outside a describe nested below the suite | | vitestExtended/no-when-in-test-title | yes | yes | error | A when condition in an it / test title | | vitestExtended/require-expect | yes | | error | An it / test that never calls expect in its own body | | vitestExtended/no-arrange-in-test | | | error | Mock or spy setup inside it / test | | vitestExtended/no-generic-http-exception-assertion | | | warn | An assertion that only names a Nest HTTP exception type | | vitestExtended/no-inherited-property-test-matrix | | | error | A subclass test that covers one inherited property on its own | | vitestExtended/no-redundant-wiring-test | | yes | error | A minimal toBeDefined() wiring test beside another executable test | | vitestExtended/no-when-in-suite-title | | | error | A suite describe title that starts with when | | vitestExtended/ordered-dto-test-groups | | yes | error | A *.dto.spec.ts suite that is not setup, then when, then properties |

no-generic-http-exception-assertion accepts exceptionNames, exemptFilePatterns, matchers, and testFilePatterns.

The test grammar those rules assume is in docs/test-grammar.md.