Add subsetting to Karma runner

[gayanW]

Karma Project Usage

Create project:

npm init -y
npm install --save-dev karma karma-jasmine jasmine-core karma-chrome-launcher karma-json-reporter

The instructions are based on:
https://karma-runner.github.io/6.4/intro/installation.html

Generate karma.conf.js:

npx karma init

# Answer the prompts:
# - Framework: jasmine
# - Require.js: no
# - Browser: ChromeHeadless
# - Test files: 
# - Files to exclude:
# - Watch files: no

Add following to karma.conf.js while keeping the current settings:

module.exports = function (config) {
  config.set({
    files: process.env.KARMA_FILES ? JSON.parse(process.env.KARMA_FILES) : [],
    ...
    plugins: [
      ...
      require('karma-json-reporter')
    ],
    jsonReporter: {
      outputFile: require('path').join(__dirname, 'test-results.json'),
      stdout: false
    },
    reporters: [..., 'json']
  });
};

Create a test file:

mkdir test

cat > test/example.spec.js << 'EOF'
describe('Example', function() {
  it('should pass', function() {
    expect(true).toBe(true);
  });

  it('should add numbers', function() {
    expect(1 + 1).toBe(2);
  });
});
EOF

Record session:

git add . && git commit -m "Initial commit"
launchable record build --name ${BUILD_NAME}
launchable record session --build ${BUILD_NAME} > session.txt

Run all tests:

find test -name "*.spec.ts" -o -name "*.spec.js" > test_list.txt
cat test_list.txt
KARMA_FILES=$(cat test_list.txt | jq -R -s -c 'split("\n")[:-1]')
npx karma start --single-run

Record tests:

launchable record tests karma test-results.json

Request subset:

cat test_list.txt | launchable subset --target 25% karma  > subset.txt

Run subset of tests:

KARMA_FILES=$(cat subset.txt | jq -R -s -c 'split("\n")[:-1]')
npx karma start --single-run

Angular Project with Karma Usage

Create project:

ng new ng-karma-app --test-runner=karma
cd ng-karma-app
npm install --save-dev karma karma-chrome-launcher karma-coverage karma-jasmine karma-jasmine-html-reporter jasmine-core karma-json-reporter @types/jasmine
ng test --no-watch --no-progress --browsers=ChromeHeadless

The instructions are based on:

• https://angular.dev/guide/testing/karma
• https://www.npmjs.com/package/karma-json-reporter

Generate karma.conf.js:

ng generate config karma

Add following to karma.conf.js while keeping the current settings:

module.exports = function (config) {
  config.set({
    ...
    plugins: [
      ...
      require('karma-json-reporter')
    ],
    jsonReporter: {
      outputFile: require('path').join(__dirname, 'test-results.json'),
      stdout: false
    },
    reporters: [..., 'json']
  });
};

Record session:

git add . && git commit -m "Initial commit"
launchable record build --name ${BUILD_NAME}
launchable record session --build ${BUILD_NAME} > session.txt

Record tests:

ng test --no-watch --no-progress --browsers=ChromeHeadless
launchable record tests karma test-results.json

Subset tests with ng:

ng test --list-tests | grep src > test_list.txt
cat test_list.txt | launchable subset --target 25% karma --with ng > subset.txt

Run subset of tests

ng test --no-watch --no-progress --browsers=ChromeHeadless --include $(cat subset.txt)