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Wasp is in beta, so keep in mind there might be some kinks / bugs, and possibly some changes with testing support in the future. If you encounter any issues, reach out to us on Discord and we will make sure to help you out!

Testing your React app

Wasp enables you to quickly and easily write both unit tests and React component tests for your frontend code. Because we already use Vite, we also support testing the web app by giving you an integrated Vitest experience out of the box.

Included Libraries

vitest: Unit test framework with native Vite support.

@vitest/ui: A nice UI for seeing your test results.

jsdom: A web browser test environment for Node.js.

@testing-library/react / @testing-library/jest-dom: Testing helpers.

msw: A server mocking library.

Test File Structure

Unit tests should live under your src/client directory and have an extension that is compatible with these glob pattern defaults. Some of the files Vitest would pick up automatically: yourFile.test.ts or YourComponent.test.jsx.

Within test files, you can import things to test using relative paths. For example, if you made a component called Counter.jsx, now you can test it by adding a file alongside it called Counter.test.jsx, which would just import from './Counter'.

Running Tests

Running wasp test client will execute Vitest in watch mode, and watch your Wasp source tree for any changes to compile as well.

  • If you want to see a live-updating UI, you can pass a --ui option, like so: wasp test client --ui
  • If you'd like to just run the tests once and exit (for example, in CI), you can pass run, like so: wasp test client run

In fact, anything after wasp test client gets passed to Vitest directly, so check out their CLI docs for more.


You should not run wasp test while running wasp start, as both will attempt to compile and write your project to .wasp/out.


Unit Tests

import { test, expect } from 'vitest'

import { areThereAnyTasks } from './Todo'

test('areThereAnyTasks', () => {

React Component Tests

import { test, expect } from 'vitest'
import { screen } from '@testing-library/react'

import { mockServer, renderInContext } from '@wasp/test'
import getTasks from '@wasp/queries/getTasks'
import Todo from './Todo'

const { mockQuery } = mockServer()

const mockTasks = [{
id: 1,
description: 'test todo 1',
isDone: true,
userId: 1

test('handles mock data', async () => {
mockQuery(getTasks, mockTasks)

renderInContext(<Todo />)

await screen.findByText('test todo 1')



React Testing Helpers

Wasp provides two React testing helpers:

  • mockQuery: Takes a Wasp Query to mock and the JSON data to return.
    • This is helpful if your Query uses useQuery.
    • Behind the scenes, this uses msw to create a server request handler that responds with the provided JSON to an HTTP request for the operation's endpoint.
    • Request handlers are cleared after each test.
  • mockApi: Similar to mockQuery, but for mocking apis instead.
    • Instead of a Wasp Query, it takes a route of the shape: mockApi({ method: HttpMethod.Get, path: '/foo/bar' }, { res: 'hello' }).
    • You can import HttpMethod like so: import { HttpMethod } from '@wasp/types'.
  • renderInContext: Takes a React component, wraps it inside a QueryClientProvider and Router, and renders it.

Testing your server-side code

Coming soon!