Karma

You can automatically detect and manage flaky tests in your Karma projects by integrating with Trunk. This document explains how to configure Karma to output JUnit XML reports that can be uploaded to Trunk for analysis.

Setup steps

Work through the steps below in order. Once you’ve finished the last one, you’ll be ready to move on to configure uploads in CI.

Generate a compatible test report

Configure the report file path or glob

Disable retries for better detection accuracy

Test uploads locally

Generating Reports

Trunk detects flaky tests by analyzing test results automatically uploaded from your CI jobs. You can do this by generating XML reports from your test runs. To generate a Trunk-compatible XML report, install the karma-junit-reporter package:

npm install --save-dev karma-junit-reporter

Add the junit reporter to your karma config file:

karma.conf.js

module.exports = function(config) {
  config.set(
    {
      reporters: ['junit'],
      junitReporter: {
        outputDir: 'test-reports',
      }
    }
  )
}

Report File Path

The outputDir and outputFile specify the location of the JUnit test report. In the example above, the JUnit would be at ./test-reports/{$browserName}.xml. You can locate the reports during uploads with the glob ./test-reports/*.xml.

Disable Retries

You need to disable automatic retries if you previously enabled them. Retries compromise the accurate detection of flaky tests. Karma doesn’t support retries out of the box, but if you implemented retries, remember to disable them.

Try It Locally

The Validate Command

You can validate your test reports using the Trunk Analytics CLI. If you don’t have it installed already, you can install and run the validate command like this:

SKU="trunk-analytics-cli-x86_64-unknown-linux.tar.gz"
curl -fL --retry 3 \
  "https://github.com/trunk-io/analytics-cli/releases/latest/download/${SKU}" \
  | tar -xz

chmod +x trunk-analytics-cli
./trunk-analytics-cli validate --junit-paths "./junit-reports/*.xml"

This will not upload anything to Trunk. To improve detection accuracy, you should address all errors and warnings before proceeding to the next steps.

Test Upload

Before modifying your CI jobs to automatically upload test results to Trunk, try uploading a single test run manually. You make an upload to Trunk using the following command:

./trunk-analytics-cli upload --junit-paths "./junit-reports/*.xml" \
    --org-url-slug <TRUNK_ORG_SLUG> \
    --token <TRUNK_ORG_TOKEN>

You can find your Trunk organization slug and token in the settings or by following these instructions. After your upload, you can verify that Trunk has received and processed it successfully in the Uploads tab. Warnings will be displayed if the report has issues.