jest-timing-reporter

A Jest reporter that collects test execution time into snapshots files as JSON which can be used later with jest-timing-action.

Usage

Install with

npm i --save-dev jest-timing-reporter

or

yarn add -D jest-timing-reporter

Then edit the jest config in your package.json (if that's the case)

{
  "jest": {
    "reporters": [
      "default",
      "jest-timing-reporter"
    ]
  },
}

Now you can run yarn test or npm run test and check that it generated tsnapshot files for each test file. Make sure you have those files tracked in git.

Output

It works pretty similar to jest's snapshots. Just that

• it will write snapshots on every run
• it won't check against the previous snapshot at all (that's done by jest-timing-action for information purpose when comparing a PR against its base branch)

Here is an example folder structure showing the __tsnapshots__ folder that contains each test file's snapshot

.
├── LICENSE
├── README.md
├── __tsnapshots__
│   └── index.test.tsnapshot
├── index.js
├── index.test.js
├── package.json
├── some
│   └── more
│       ├── __tsnapshots__
│       │   └── more.test.tsnapshot
│       ├── more.test.js
│       └── tests
│           ├── __tsnapshots__
│           │   └── good.test.tsnapshot
│           └── good.test.js
├── yarn-error.log
└── yarn.lock

Further Work

Currently this is just a small script done as a proof-of-concept to explore jest, GH actions, GH API, etc. plus providing some basic "smoke-test" like information to try to detect changes that impact performance of your code. For sure this could evolve to a much more useful "continuous code quality measure" solution.

• Handle tests being renamed
• Handle it being moved into a different describe or a new describe
• Handle file moved (remove old file)
• Handle file deleted (remove old file)