Incremental Angular unit tests in CI

A RedFroggy project

Most of the times, when an Angular code change is made by a developer, all unit tests are run in CI. This project is a proof of concept on how only run impacted unit tests based on a commit change.

Getting started

• npm i angular-incremental-tests -D
• In your package.json file add the following configuration

"incrementalTests": {
    "ignoredFilesPatterns": [
      ".md",
      ".eslint*",
      "*.json",
      "!package.json",
      "!package-lock.json",
      ".mustache",
      "*.js"
    ],
    "rootDir": "src/app",
    "testCommand": "npm run test"
  }

Option	Description
ignoredFilesPatterns	List of files patterns to ignore
rootDir	your application root directory
testCommand	The test command to run

• In your package.json file, add the following script:
  • "test:incremental": "node node_modules/angular-incremental-tests/index.js"
• You can then run: npm run test:incremental in your ci script.

Environment variables

• The following command is run to list all files names changed in CI between two commits: git diff --name-only CI_COMMIT_BEFORE_SHA CI_COMMIT_SHA
• So you need to set both environment variables: CI_COMMIT_BEFORE_SHA and CI_COMMIT_SHA