jest-coverage-thresholds-bumper

jest-coverage-thresholds-bumper

Tool for Jest testing library that automatically bumps up code coverage thresholds as real code coverage improves. Inspired by https://github.com/Koleok/jest-coverage-ratchet, but I decided to re-write without Ramda (it looks cool, but readability sucks IMO) and to add features I missed.

Tool supports jest.config.json, jest.config.js, and jest.config.ts configuration files, as well as jest section in package.json.

Value

Code coverage by tests may drop accidentally if you forget to cover new code with tests. It is easy to notice if your coverage thresholds are matching real coverage exactly. If you do have to decrease coverage then it has to be done explicitly and this fact will be more visible in pull requests.

Installation

Assuming that you already have Jest installed, call:

npm install -D jest-coverage-thresholds-bumper

Usage

• Make sure that Jest has code coverage enabled and uses json-summary reporter. It is needed to produce coverage results for analysis.
• Ensure that you have some threshold values specified (you can start with 0). jest-coverage-thresholds-bumper only updates existing values. Example:

// jest.config.js
...
  coverageThreshold: {
    global: {
      lines: 80,
      statements: 80,
      branches: 80,
      functions: 80,
    }
  }
...

• Call jest-coverage-thresholds-bumper after running tests, for example:

// package.json
...
"scripts": {
    "test": "jest",
    "posttest": "jest-coverage-thresholds-bumper",
}
...

When tool is called it finds coverage information, compares results with threshold values and bumps up values if results are higher. Note that only defined thresholds are bumped up - i.e. if no thresholds exists nothing will be bumped.

Options

Usage: jest-coverage-thresholds-bumper <command> [options]

Options:
  --coverage-summary-path  Path to Jest coverage results          [string] [default: "./coverage/coverage-summary.json"]
  --margin                 Minimal threshold increase                                              [number] [default: 0]
  --dry-run                Do analysis, but don't change any thresholds                                        [boolean]
  --silent                 No console output unless something goes wrong                                       [boolean]
  --help                   Show help                                                                           [boolean]
  --version                Show version number                                                                 [boolean]