How do you debug Jest Tests?

问题

I can't find any information on debugging my unit tests written with Jest.

How do you debug Jest Tests ?

回答1:

You can use Chrome DevTools to debug Jest tests.

First, start Node debugger in your project:

node --inspect-brk <path to jest.js> --runInBand <path to your test file>

Examples:

If you install Jest locally (Linux example):

node --inspect-brk ./node_modules/jest/bin/jest.js --runInBand mymodule/test.js
If you install Jest globally (Windows example):

node --inspect-brk "C:\\Program Files\\nodejs\\node_modules\\jest\\bin\\jest.js" --runInBand mymodule\\test.js

Then, you can open the Google Chrome browser, and type in the address bar:

chrome://inspect

Now click the inspect link under "Remote Target" to open Chrome DevTools.

Note that you probably need to add the source code folder to the workspace in chrome-devtools, so as to be able to set breakpoints.

Now you can press F8 to start debugging.

[FYI]:

My Node version: v10.11.0
My Jest version: 23.6.0
My Google Chrome version: 71.0.3578.98

回答2:

For anyone seeking an answer, you debug jest with node-inspector. However this is a very slow process (2-5 minutes to debug a single test), and wasn't very useful in actual usage.

I haven't found a better way to debug Jest, however I have seen a lot of people doing the extra work to make jasmine or mocha work with react components. So that may be a more viable option until node-inspector is actually usable.

回答3:

This is my basic config for debugging Jest in VSCode, add to your launch configurations within settings.json

"launch" : {
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Jest",
      "program": "${workspaceRoot}/node_modules/jest/bin/jest.js",
      "args": [
          "-i"
      ],
       "skipFiles": [
        "<node_internals>/**/*.js", "node_modules",
      ]
    }
  ],
},

回答4:

Run

node --debug-brk node_modules/.bin/jest

in your project directory. It should start the node process paused an listening (usually at port 5858) for a debugger. Visual Studio Code is an example of a nice graphical debugger for node.js that can be used to connect to the listening node process.

来源：https://stackoverflow.com/questions/33247602/how-do-you-debug-jest-tests

标签

unit-testing

debugging

jestjs