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prefer-test-fixture-reuse

Reuse a requested test fixture instead of constructing another instance of its class.

reuseFixture Rule source Tests Catalog JSON

Why

A second constructor bypasses the fixture's overrides, caching, configuration and cleanup ownership.

Fix

Use the requested fixture. Supply a typed factory fixture when a test requires different configuration or multiple independent instances.

Examples

Before — flagged The test constructs the store its fixture supplied

src/store.test.ts

import { test as base } from "vitest";
class Store {}
const test = base.extend({
  store: async ({}, use) => {
    await use(new Store());
  },
});
test("reads", ({ store }) => {
  const other = new Store();
  expect(other).toBeDefined();
});

After — preferred Request and use the store fixture

src/store.test.ts

import { test as base } from "vitest";
class Store {}
const test = base.extend({
  store: async ({}, use) => {
    await use(new Store());
  },
});
test("reads", ({ store }) => {
  expect(store).toBeDefined();
});