Compatibility

Supported test frameworks:

The instrumentation works at runtime, so any transpilers such as TypeScript, Webpack, or Babel are supported out-of-the-box.

Configuring reporting method

To report test results to Datadog, you need to configure the Datadog JavaScript library:

Installing the JavaScript tracer

To install the JavaScript Tracer, run:

yarn add --dev dd-trace

For more information, see the JavaScript Tracer installation documentation.

Instrument your tests

NODE_OPTIONS="-r dd-trace/ci/init" DD_TEST_SESSION_NAME=unit-tests yarn test

{
  "scripts": {
    "test": "NODE_OPTIONS=\"--max-old-space-size=12288 ${NODE_OPTIONS:-}\" jest"
  }
}

  it('sum function can sum', () => {
    const testSpan = require('dd-trace').scope().active()
    testSpan.setTag('team_owner', 'my_team')
    // test continues normally
    // ...
  })

  it('sum function can sum', () => {
    const testSpan = require('dd-trace').scope().active()
    testSpan.setTag('memory_allocations', 16)
    // test continues normally
    // ...
  })

NODE_OPTIONS="-r dd-trace/ci/init" DD_TEST_SESSION_NAME=e2e-tests yarn test:e2e

{
  "scripts": {
    "test": "NODE_OPTIONS=\"--max-old-space-size=12288 ${NODE_OPTIONS:-}\" jest"
  }
}

test('user profile', async ({ page }) => {
  test.info().annotations.push({
    type: 'DD_TAGS[test.memory.usage]', // DD_TAGS is mandatory and case sensitive
    description: 'low',
  });
  test.info().annotations.push({
    type: 'DD_TAGS[test.task.id]',
    description: '41123',
  });
  // ...
});

test('landing page', async ({ page }) => {
  test.info().annotations.push({
    type: 'DD_TAGS[test.cpu.usage]',
    description: 'high',
  });
  // ...
});

{
  "type": "DD_TAGS[$TAG_NAME]",
  "description": "$TAG_VALUE"
}

test('user profile', async ({ page }) => {
  test.info().annotations.push({
    type: 'DD_TAGS[test.memory.allocations]', // DD_TAGS is mandatory and case sensitive
    description: 16, // this is a number
  });
});

{
  "type": "DD_TAGS[$TAG_NAME]",
  "description": $TAG_VALUE
}

NODE_OPTIONS="-r dd-trace/ci/init" DD_TEST_SESSION_NAME=integration-tests yarn test:integration

{
  "scripts": {
    "test": "NODE_OPTIONS=\"--max-old-space-size=12288 ${NODE_OPTIONS:-}\" jest"
  }
}

  When('the function is called', function () {
    const stepSpan = require('dd-trace').scope().active()
    testSpan.setTag('team_owner', 'my_team')
    // test continues normally
    // ...
  })

  When('the function is called', function () {
    const stepSpan = require('dd-trace').scope().active()
    testSpan.setTag('memory_allocations', 16)
    // test continues normally
    // ...
  })

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents: require('dd-trace/ci/cypress/plugin'),
    supportFile: 'cypress/support/e2e.js'
  }
})

// Your code can be before this line
// require('./commands')
require('dd-trace/ci/cypress/support')
// Also supported:
// import 'dd-trace/ci/cypress/support'
// Your code can also be after this line
// Cypress.Commands.add('login', (email, pw) => {})

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      // your previous code is before this line
      return require('dd-trace/ci/cypress/plugin')(on, config)
    }
  }
})

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      require('dd-trace/ci/cypress/plugin')(on, config)
      // other plugins
      on('after:run', (details) => {
        // other 'after:run' handlers
        // important that this function call is returned
        return require('dd-trace/ci/cypress/after-run')(details)
      })
    }
  }
})

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      require('dd-trace/ci/cypress/plugin')(on, config)
      // other plugins
      on('after:spec', (...args) => {
        // other 'after:spec' handlers
        // Important that this function call is returned
        // Important that all the arguments are passed
        return require('dd-trace/ci/cypress/after-spec')(...args)
      })
    }
  }
})

{
  "pluginsFile": "dd-trace/ci/cypress/plugin"
}

module.exports = (on, config) => {
  // your previous code is before this line
  return require('dd-trace/ci/cypress/plugin')(on, config)
}

// Your code can be before this line
// require('./commands')
require('dd-trace/ci/cypress/support')
// Your code can also be after this line
// Cypress.Commands.add('login', (email, pw) => {})

module.exports = (on, config) => {
  // your previous code is before this line
  require('dd-trace/ci/cypress/plugin')(on, config)
  on('after:run', (details) => {
    // other 'after:run' handlers
    // important that this function call is returned
    return require('dd-trace/ci/cypress/after-run')(details)
  })
}

module.exports = (on, config) => {
  // your previous code is before this line
  require('dd-trace/ci/cypress/plugin')(on, config)
  on('after:spec', (...args) => {
    // other 'after:spec' handlers
    // Important that this function call is returned
    // Important that all the arguments are passed
    return require('dd-trace/ci/cypress/after-run')(...args)
  })
}

DD_TEST_SESSION_NAME=ui-tests yarn test:ui

beforeEach(() => {
  cy.task('dd:addTags', {
    'before.each': 'certain.information'
  })
})
it('renders a hello world', () => {
  cy.task('dd:addTags', {
    'team.owner': 'ui'
  })
  cy.get('.hello-world')
    .should('have.text', 'Hello World')
})

it('renders a hello world', () => {
  cy.task('dd:addTags', {
    'memory_allocations': 16
  })
  cy.get('.hello-world')
    .should('have.text', 'Hello World')
})

NODE_OPTIONS="--import dd-trace/register.js -r dd-trace/ci/init" DD_TEST_SESSION_NAME=smoke-tests yarn test:smoke

{
  "scripts": {
    "test": "NODE_OPTIONS=\"--max-old-space-size=12288 ${NODE_OPTIONS:-}\" vitest run"
  }
}

How to fix “Cannot find module ‘dd-trace/ci/init’” errors

When using dd-trace, you might encounter the following error message:

 Error: Cannot find module 'dd-trace/ci/init'

This might be because of an incorrect usage of NODE_OPTIONS.

For example, if your GitHub Action looks like this:

jobs:
  my-job:
    name: Run tests
    runs-on: ubuntu-latest
    # Invalid NODE_OPTIONS
    env:
      NODE_OPTIONS: -r dd-trace/ci/init
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3
      - name: Install node
        uses: actions/setup-node@v3
      - name: Install dependencies
        run: npm install
      - name: Run tests
        run: npm test

Note: This does not work because NODE_OPTIONS are interpreted by every node process, including npm install. If you try to import dd-trace/ci/init before it’s installed, this step fails.

Your GitHub Action should instead look like this:

jobs:
  my-job:
    name: Run tests
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3
      - name: Install node
        uses: actions/setup-node@v3
      - name: Install dependencies
        run: npm install
      - name: Run tests
        run: npm test
        env:
          NODE_OPTIONS: -r dd-trace/ci/init

Follow these best practices:

• Make sure the NODE_OPTIONS environment variable is only set to the process running tests.
• Specifically avoid defining NODE_OPTIONS in the global environment variables settings in your pipeline or job definition.

Using Yarn 2 or later

If you’re using yarn>=2 and a .pnp.cjs file, you might also get the same error:

 Error: Cannot find module 'dd-trace/ci/init'

You can fix it by setting NODE_OPTIONS to the following:

NODE_OPTIONS="-r $(pwd)/.pnp.cjs -r dd-trace/ci/init" yarn test

Reporting code coverage

When tests are instrumented with Istanbul, the Datadog Tracer (v3.20.0 or later) reports it under the test.code_coverage.lines_pct tag for your test sessions.

You can see the evolution of the test coverage in the Coverage tab of a test session.

For more information, see Code Coverage.

Configuration settings

The following is a list of the most important configuration settings that can be used with the tracer.

test_session.name

Use it to identify a group of tests, such as integration-tests, unit-tests or smoke-tests.
Environment variable: DD_TEST_SESSION_NAME
Default: (CI job name + test command)
Example: unit-tests, integration-tests, smoke-tests

service

Name of the service or library under test.
Environment variable: DD_SERVICE
Default: (test framework name)
Example: my-ui

env

Name of the environment where tests are being run.
Environment variable: DD_ENV
Default: none
Examples: local, ci

url

Datadog Agent URL for trace collection in the form http://hostname:port.
Environment variable: DD_TRACE_AGENT_URL
Default: http://localhost:8126

For more information about service and env reserved tags, see Unified Service Tagging. All other Datadog Tracer configuration options can also be used.

Collecting Git metadata

Datadog uses Git information for visualizing your test results and grouping them by repository, branch, and commit. Git metadata is automatically collected by the test instrumentation from CI provider environment variables and the local .git folder in the project path, if available.

If you are running tests in non-supported CI providers or with no .git folder, you can set the Git information manually using environment variables. These environment variables take precedence over any auto-detected information. Set the following environment variables to provide Git information:

DD_GIT_REPOSITORY_URL

URL of the repository where the code is stored. Both HTTP and SSH URLs are supported.
Example: git@github.com:MyCompany/MyApp.git, https://github.com/MyCompany/MyApp.git

DD_GIT_BRANCH

Git branch being tested. Leave empty if providing tag information instead.
Example: develop

DD_GIT_TAG

Git tag being tested (if applicable). Leave empty if providing branch information instead.
Example: 1.0.1

DD_GIT_COMMIT_SHA

Full commit hash.
Example: a18ebf361cc831f5535e58ec4fae04ffd98d8152

DD_GIT_COMMIT_MESSAGE

Commit message.
Example: Set release number

DD_GIT_COMMIT_AUTHOR_NAME

Commit author name.
Example: John Smith

DD_GIT_COMMIT_AUTHOR_EMAIL

Commit author email.
Example: john@example.com

DD_GIT_COMMIT_AUTHOR_DATE

Commit author date in ISO 8601 format.
Example: 2021-03-12T16:00:28Z

DD_GIT_COMMIT_COMMITTER_NAME

Commit committer name.
Example: Jane Smith

DD_GIT_COMMIT_COMMITTER_EMAIL

Commit committer email.
Example: jane@example.com

DD_GIT_COMMIT_COMMITTER_DATE

Commit committer date in ISO 8601 format.
Example: 2021-03-12T16:00:28Z

Manual testing API

If you use Jest, Mocha, Cypress, Playwright, Cucumber, or Vitest, do not use the manual testing API, as Test Optimization automatically instruments them and sends the test results to Datadog. The manual testing API is incompatible with already supported testing frameworks.

Use the manual testing API only if you use an unsupported testing framework or have a different testing mechanism.

The manual testing API leverages the node:diagnostics_channel module from Node.js and is based on channels you can publish to:

const { channel } = require('node:diagnostics_channel')

const { describe, test, beforeEach, afterEach, assert } = require('my-custom-test-framework')

const testStartCh = channel('dd-trace:ci:manual:test:start')
const testFinishCh = channel('dd-trace:ci:manual:test:finish')
const testSuite = __filename

describe('can run tests', () => {
  beforeEach((testName) => {
    testStartCh.publish({ testName, testSuite })
  })
  afterEach((status, error) => {
    testFinishCh.publish({ status, error })
  })
  test('first test will pass', () => {
    assert.equal(1, 1)
  })
})

Test start channel

Grab this channel by its ID dd-trace:ci:manual:test:start to publish that a test is starting. A good place to do this is a beforeEach hook or similar.

const { channel } = require('node:diagnostics_channel')
const testStartCh = channel('dd-trace:ci:manual:test:start')

// ... code for your testing framework goes here
  beforeEach(() => {
    const testDefinition = {
      testName: 'a-string-that-identifies-this-test',
      testSuite: 'what-suite-this-test-is-from.js'
    }
    testStartCh.publish(testDefinition)
  })
// code for your testing framework continues here ...

The payload to be published has attributes testName and testSuite, both strings, that identify the test that is about to start.

Test finish channel

Grab this channel by its ID dd-trace:ci:manual:test:finish to publish that a test is ending. A good place to do this is an afterEach hook or similar.

const { channel } = require('node:diagnostics_channel')
const testFinishCh = channel('dd-trace:ci:manual:test:finish')

// ... code for your testing framework goes here
  afterEach(() => {
    const testStatusPayload = {
      status: 'fail',
      error: new Error('assertion error')
    }
    testStartCh.publish(testStatusPayload)
  })
// code for your testing framework continues here ...

The payload to be published has attributes status and error:

• status is a string that takes one of three values:

  • 'pass' when a test passes.
  • 'fail' when a test fails.
  • 'skip' when a test has been skipped.

• error is an Error object containing the reason why a test failed.

Add tags channel

Grab this channel by its ID dd-trace:ci:manual:test:addTags to publish that a test needs custom tags. This can be done within the test function:

const { channel } = require('node:diagnostics_channel')
const testAddTagsCh = channel('dd-trace:ci:manual:test:addTags')

// ... code for your testing framework goes here
  test('can sum', () => {
    testAddTagsCh.publish({ 'test.owner': 'my-team', 'number.assertions': 3 })
    const result = sum(2, 1)
    assert.equal(result, 3)
  })
// code for your testing framework continues here ...

The payload to be published is a dictionary <string, string|number> of tags or measures that are added to the test.

Run the tests

When the test start and end channels are in your code, run your testing framework like you normally do, including the following environment variables:

NODE_OPTIONS="-r dd-trace/ci/init" DD_TEST_SESSION_NAME=custom-tests yarn run-my-test-framework

Known limitations

Browser tests

Browser tests executed with mocha, jest, cucumber, cypress, playwright, and vitest are instrumented by dd-trace-js, but visibility into the browser session itself is not provided by default (for example, network calls, user actions, page loads, and more.).

If you want visibility into the browser process, consider using RUM & Session Replay. When using Cypress, test results and their generated RUM browser sessions and session replays are automatically linked. For more information, see the Instrumenting your browser tests with RUM guide.

Cypress interactive mode

Cypress interactive mode (which you can enter by running cypress open) is not supported by Test Optimization because some cypress events, such as before:run, are not fired. If you want to try it anyway, pass experimentalInteractiveRunEvents: true to the cypress configuration file.

Jest’s test.concurrent

Jest’s test.concurrent is not supported.

Jest’s --forceExit

Jest’s –forceExit option may cause data loss. Datadog tries to send data immediately after your tests finish, but shutting down the process abruptly can cause some requests to fail. Use --forceExit with caution.

Mocha’s --exit

Mocha’s –exit option may cause data loss. Datadog tries to send data immediately after your tests finish, but shutting down the process abruptly can cause some requests to fail. Use --exit with caution.

Best practices

Follow these practices to take full advantage of the testing framework and Test Optimization.

Parameterized tests

Whenever possible, leverage the tools that testing frameworks provide for parameterized tests. For example, for jest:

Avoid this:

[[1,2,3], [3,4,7]].forEach((a,b,expected) => {
  test('sums correctly', () => {
    expect(a+b).toEqual(expected)
  })
})

And use test.each instead:

test.each([[1,2,3], [3,4,7]])('sums correctly %i and %i', (a,b,expected) => {
  expect(a+b).toEqual(expected)
})

For mocha, use mocha-each:

const forEach = require('mocha-each');
forEach([
  [1,2,3],
  [3,4,7]
])
.it('adds %i and %i then returns %i', (a,b,expected) => {
  expect(a+b).to.equal(expected)
});

When you use this approach, both the testing framework and Test Optimization can tell your tests apart.

Test session name DD_TEST_SESSION_NAME

Use DD_TEST_SESSION_NAME to define the test session name for your tests (test_session.name tag). Use this to identify a group of tests. Examples of values for this tag would be:

• unit-tests
• integration-tests
• smoke-tests
• flaky-tests
• ui-tests
• backend-tests

If DD_TEST_SESSION_NAME is not specified, the default value used is a combination of:

• CI job name
• Command used to run the tests (such as yarn test)

The test session name should be unique within a repository to help you distinguish different groups of tests.

When to use DD_TEST_SESSION_NAME

If your tests are run with commands that include a dynamic string, such as:

• yarn test --temp-dir=/var/folders/t1/rs2htfh55mz9px2j4prmpg_c0000gq/T
• pnpm vitest --temp-dir=/var/folders/t1/rs2htfh55mz9px2j4prmpg_c0000gq/T

The default value for the test session name will be unstable. It is recommended to use DD_TEST_SESSION_NAME in this case.

Further reading

Additional helpful documentation, links, and articles:

Forwarding Environment Variables for Tests in ContainersDOCUMENTATION Explore Test Results and PerformanceDOCUMENTATION Speed up your test jobs with Test Impact AnalysisDOCUMENTATION Troubleshooting Test OptimizationDOCUMENTATION