mhmdnzr / unit-test-nextjs

Learning unit test in nextjs

Test

Write test for program had three steps:

• End to End (E2E) => using cypress or selenium
• Integration
• Unit

Installation packages

$ npm install --save-dev jest typescript ts-jest @types/jest

$ npx ts-jest config:init

$ npm i --save-dev @testing-library/react @testing-library/user-event @testing-library/dom @testing-library/jest-dom  

add this to jest.config.js:

module.exports = {
    "testEnvironment": "jsdom"
}

[check stacks-overflow] (https://stackoverflow.com/questions/69227566/consider-using-the-jsdom-test-environment)

after all we should get this line of error!

● Validation Error:

  Test environment jest-environment-jsdom cannot be found. Make sure the testEnvironment configuration option points to an existing node module.

  Configuration Documentation:
  https://jestjs.io/docs/configuration


As of Jest 28 "jest-environment-jsdom" is no longer shipped by default, make sure to install it separately.

u should install this package:

$ npm install -D jest-environment-jsdom  

TDD (Test Driven Development)

that's have a cycle: Write failing test => Make the test pass => Refactor

Live testing

Please use this webpage: [real time testing] (https://testing-playground.com)