/pinia-skilld

Testing

Unit testing a store

Create a fresh pinia per test and make it active:

import { setActivePinia, createPinia } from 'pinia'
import { useCounterStore } from '../src/stores/counter'

beforeEach(() => {
  setActivePinia(createPinia())
})

it('increments', () => {
  const counter = useCounterStore()
  counter.increment()
  expect(counter.n).toBe(1)
})

setActivePinia sets the instance that bare useStore() calls resolve to [dist/pinia.js:70].

Plugins only run after the pinia is installed in an app. Use a fake app:

const app = createApp({})
beforeEach(() => {
  const pinia = createPinia().use(somePlugin)
  app.use(pinia)
  setActivePinia(pinia)
})

Dispose instances between complex tests with disposePinia(pinia) [dist/pinia.d.ts:589-595].

Component tests: @pinia/testing 2.x

createTestingPinia() stubs every action as a spy by default:

import { mount } from '@vue/test-utils'
import { createTestingPinia } from '@pinia/testing'
import { useSomeStore } from '@/stores/myStore'

const wrapper = mount(Component, {
  global: { plugins: [createTestingPinia()] },
})

const store = useSomeStore()
store.someAction()
expect(store.someAction).toHaveBeenCalledTimes(1)

Options:

• stubActions: false runs the real implementations, still spied.
• stubActions: ['increment', 'reset'] stubs only named actions; an empty array stubs none; a function (name, store) => boolean decides per action.
• initialState: { counter: { n: 20 } } patches state at store creation.
• createSpy: vi.fn when vitest globals: true is off, or for other frameworks.

Pass store plugins through the plugins option. Do not call testingPinia.use(); plugins added that way are not applied.

Getters stay live computed in tests. store.double = 3 forces a value; set it back to undefined to restore computation.

Install: npm i -D @pinia/testing. Use 2.x with pinia 4 (https://github.com/vuejs/pinia/releases).

How the testing bypass works

A testing pinia sets _testing on the instance. In NODE_ENV === "test", useStore() ignores its pinia argument and uses the active testing pinia instead [dist/pinia.js:534-535,1307]. This is why setActivePinia(createTestingPinia()) redirects bare useStore() calls in tests.

https://pinia.vuejs.org/cookbook/testing.html