How to add Vue Test Utils with Jest to already existing Vue-CLI 3 project?

Question

I want to test an already existing Vue-CLI 3 project. I haven't initialized the testing preset when I was creating the project. I have searched, but haven't found any suitable results. I read the documentation also, but it said to add testing when creating the project.

Answer 1

From your project root directory, enter the following command to add @vue/test-utils and jest:

vue add unit-jest

The command output should look similar to this:

$ vue add unit-jest

📦  Installing @vue/cli-plugin-unit-jest...

+ @vue/cli-plugin-unit-jest@3.7.0
added 282 packages from 167 contributors, removed 2 packages and audited 42205 packages in 9.693s
found 63 low severity vulnerabilities
  run `npm audit fix` to fix them, or `npm audit` for details
✔  Successfully installed plugin: @vue/cli-plugin-unit-jest


🚀  Invoking generator for @vue/cli-plugin-unit-jest...
📦  Installing additional dependencies...

added 12 packages from 11 contributors, updated 1 package, moved 4 packages and audited 42427 packages in 7.895s
found 64 low severity vulnerabilities
  run `npm audit fix` to fix them, or `npm audit` for details
✔  Successfully invoked generator for plugin: @vue/cli-plugin-unit-jest
   The following files have been updated / added:

     jest.config.js
     tests/unit/.eslintrc.js
     tests/unit/example.spec.js
     package-lock.json
     package.json

   You should review these changes with git diff and commit them.