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Test Optimization is not available in the selected site () at this time.

Compatibility

Supported test frameworks:

Test FrameworkVersionNotes
Jest>= 24.8.0Only jsdom (in the jest-environment-jsdom package) and node (in the jest-environment-node package) are supported as test environments. Custom environments like @jest-runner/electron/environment in jest-electron-runner are not supported.

Only jest-circus is supported as testRunner.

test.concurrent is not supported.
Mocha>= 5.2.0Mocha >= 9.0.0 has partial support.
Cucumber>= 7.0.0
Cypress>= 6.7.0
Playwright>= 1.18.0
Vitest>= 1.16.0Supported from dd-trace>=4.42.0 and dd-trace>=5.18.0. Only supported from Node.js>=18.19 or Node.js>=20.6

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:

We support auto-instrumentation for the following CI providers:

CI ProviderAuto-Instrumentation method
GitHub ActionsDatadog Test Visibility Github Action
JenkinsUI-based configuration with Datadog Jenkins plugin
GitLabDatadog Test Visibility GitLab Script
CircleCIDatadog Test Visibility CircleCI Orb

If you are using auto-instrumentation for one of these providers, you can skip the rest of the setup steps below.

Note: Auto-instrumentation is not supported for Cypress tests. To instrument Cypress tests, follow the manual instrumentation steps outlined below.
Agentless mode is available in Datadog JavaScript library versions >= 2.5.0
GitHub Actions나 CircleCI와 같이 기본 작업자 노드에 액세스하지 않고 클라우드 CI 공급자를 사용할 경우, 라이브러리를 구성해 에이전트리스 모드로 사용하세요. 이 모드를 이용하려면 다음 환경 변수를 설정하세요.
DD_CIVISIBILITY_AGENTLESS_ENABLED=true (필수)
에이전트리스 모드 활성화 또는 비활성화
기본값: false
DD_API_KEY (필수)
테스트 결과를 업로드하는 데 사용되는 Datadog API 키
기본값: (empty)

추가로 데이터를 보낼 Datadog 사이트를 구성하세요.

DD_SITE (필수)
결과를 업로드할 Datadog 사이트
기본값: datadoghq.com

Jenkins 또는 자체 관리형 GitLab CI와 같은 온프레미스 CI 공급자에서 테스트를 실행하는 경우, 에이전트 설치 지침에 따라 각 작업자 노드에 Datadog 에이전트를 설치합니다. 자동으로 테스트 결과를 로그기본 호트스 메트릭과 연결할 수 있기 때문에 이 옵션을 추천합니다.

쿠버네티스 실행기를 사용하는 경우 Datadog에서는 Datadog 연산자를 사용할 것을 권고합니다. 연산자에는 Datadog 허용 제어기가 포함되어 있어 빌드 파드에 자동으로 추적기 라이브러리를 삽입합니다. 참고: Datadog 연산자를 사용할 경우 허용 제어기가 작업을 해주기 때문에 추적기 라이브러리를 다운로드 받고 삽입할 필요가 없습니다. 따라서 아래 해당 단계를 건너뛰어도 됩니다. 그러나 테스트 가시화 기능을 사용할 때 필요한 파드의 환경 변수나 명령줄 파라미터는 설정해야 합니다.

쿠버네티스를 사용하지 않거나 Datadog 허용 제어기를 사용할 수 없고 CI 공급자가 컨테이너 기반 실행기를 사용하는 경우, 추적기를 실행하는 빌드 컨테이너에서 환경 변수 DD_TRACE_AGENT_URL(기본값 http://localhost:8126)를 해당 컨테이너 내에서 액세스할 수 있는 엔드포인트로 설정합니다. 참고: 빌드 내에서 localhost를 사용하면 기본 작업자 노드나 에이전트를 실행하는 컨테이너를 참조하지 않고 컨테이너 자체를 참조합니다.

DD_TRACE_AGENT_URL 은 프로토콜과 포트(예: http://localhost:8126)를 포함하고 DD_AGENT_HOSTDD_TRACE_AGENT_PORT보다 우선하며, CI Visibility를 위해 Datadog 에이전트의 URL을 설정하는 데 권장되는 설정 파라미터입니다.

Datdog 에이전트에 연결하는 데 아직 문제가 있다면 에이전트리스 모드를 사용해 보세요. 참고: 이 방법을 사용할 경우 테스트가 로그인프라스트럭처 메트릭과 상관 관계를 수립하지 않습니다.

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

Set the NODE_OPTIONS environment variable to -r dd-trace/ci/init. Run your tests as you normally would, specifying the environment where the tests are run in the DD_ENV environment variable. For example, set DD_ENV to local when running tests on a developer workstation, or ci when running them on a CI provider:

NODE_OPTIONS="-r dd-trace/ci/init" DD_ENV=ci DD_SERVICE=my-javascript-app yarn test

Note: If you set a value for NODE_OPTIONS, make sure it does not overwrite -r dd-trace/ci/init. This can be done using the ${NODE_OPTIONS:-} clause:

package.json

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

Adding custom tags to tests

You can add custom tags to your tests by using the current active span:

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

To create filters or group by fields for these tags, you must first create facets. For more information about adding tags, see the Adding Tags section of the Node.js custom instrumentation documentation.

Adding custom measures to tests

Just like tags, you can add custom measures to your tests by using the current active span:

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

For more information about custom measures, see the Add Custom Measures Guide.

Set the NODE_OPTIONS environment variable to -r dd-trace/ci/init. Run your tests as you normally would, specifying the environment where the tests are run in the DD_ENV environment variable. For example, set DD_ENV to local when running tests on a developer workstation, or ci when running them on a CI provider:

NODE_OPTIONS="-r dd-trace/ci/init" DD_ENV=ci DD_SERVICE=my-javascript-app yarn test

Note: If you set a value for NODE_OPTIONS, make sure it does not overwrite -r dd-trace/ci/init. This can be done using the ${NODE_OPTIONS:-} clause:

package.json

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

Adding custom tags to tests

You can add custom tags to your tests by using the custom annotations API from Playwright:

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',
  });
  // ...
});

The format of the annotations is the following, where $TAG_NAME and $TAG_VALUE are strings representing tag name and value respectively:

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

Adding custom measures to tests

Custom measures also use custom annotations:

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
  });
});

The format of the annotations is the following, where $TAG_NAME is a string representing the tag name and $TAG_VALUE is a number representing the tag value:

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

Note: description values in annotations are typed as strings. Numbers also work, but you may need to disable the typing error with // @ts-expect-error.

Important: The DD_TAGS prefix is mandatory and case sensitive.

Set the NODE_OPTIONS environment variable to -r dd-trace/ci/init. Run your tests as you normally would, specifying the environment where the tests are run in the DD_ENV environment variable. For example, set DD_ENV to local when running tests on a developer workstation, or ci when running them on a CI provider:

NODE_OPTIONS="-r dd-trace/ci/init" DD_ENV=ci DD_SERVICE=my-javascript-app yarn test

Note: If you set a value for NODE_OPTIONS, make sure it does not overwrite -r dd-trace/ci/init. This can be done using the ${NODE_OPTIONS:-} clause:

package.json

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

Adding custom tags to tests

You can add custom tags to your test by grabbing the current active span:

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

To create filters or group by fields for these tags, you must first create facets. For more information about adding tags, see the Adding Tags section of the Node.js custom instrumentation documentation.

Adding custom measures to tests

You may also add custom measures to your test by grabbing the current active span:

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

For more information about custom measures, see the Add Custom Measures Guide.

Cypress version 10 or later

Use the Cypress API documentation to learn how to use plugins for cypress>=10.

In your cypress.config.js file, set the following:

cypress.config.js

const { defineConfig } = require('cypress')

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

Add the following line to the top level of your 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) => {})

If you’re using other Cypress plugins, your cypress.config.js file should contain the following:

cypress.config.js

const { defineConfig } = require('cypress')

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

Cypress after:run event

Datadog requires the after:run Cypress event to work, and Cypress does not allow multiple handlers for that event. If you defined handlers for after:run already, add the Datadog handler manually by importing 'dd-trace/ci/cypress/after-run':

cypress.config.js

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)
      })
    }
  }
})

Cypress after:spec event

Datadog requires the after:spec Cypress event to work, and Cypress does not allow multiple handlers for that event. If you defined handlers for after:spec already, add the Datadog handler manually by importing 'dd-trace/ci/cypress/after-spec':

cypress.config.js

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)
      })
    }
  }
})

Cypress before version 10

These are the instructions if you’re using a version older than cypress@10. See the Cypress documentation for more information about migrating to a newer version.

  1. Set pluginsFile to "dd-trace/ci/cypress/plugin", for example, through cypress.json:

cypress.json

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

If you already defined a pluginsFile, initialize the instrumentation with:

cypress/plugins/index.js

module.exports = (on, config) => {
  // your previous code is before this line
  require('dd-trace/ci/cypress/plugin')(on, config)
}
  1. Add the following line to the top level of your supportFile:

cypress/support/index.js

// 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) => {})

Cypress after:run event

Datadog requires the after:run Cypress event to work, and Cypress does not allow multiple handlers for that event. If you defined handlers for after:run already, add the Datadog handler manually by importing 'dd-trace/ci/cypress/after-run':

cypress/plugins/index.js

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)
  })
}

Cypress after:spec event

Datadog requires the after:spec Cypress event to work, and Cypress does not allow multiple handlers for that event. If you defined handlers for after:spec already, add the Datadog handler manually by importing 'dd-trace/ci/cypress/after-spec':

cypress/plugins/index.js

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)
  })
}

Run your tests as you normally do, specifying the environment where test are being run (for example, local when running tests on a developer workstation, or ci when running them on a CI provider) in the DD_ENV environment variable. For example:

DD_ENV=ci DD_SERVICE=my-ui-app npm test

Adding custom tags to tests

To add additional information to your tests, such as the team owner, use cy.task('dd:addTags', { yourTags: 'here' }) in your test or hooks.

For example:

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')
})

To create filters or group by fields for these tags, you must first create facets. For more information about adding tags, see the Adding Tags section of the Node.js custom instrumentation documentation.

Adding custom measures to tests

To add custom measures to your tests, such as memory allocations, use cy.task('dd:addTags', { yourNumericalTags: 1 }) in your test or hooks.

For example:

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

For more information about custom measures, see the Add Custom Measures Guide.

Cypress - RUM integration

If the browser application being tested is instrumented using Browser Monitoring, the 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.

Note: Vitest is ESM first, so its configuration is different from other test frameworks.

vitest and dd-trace require Node.js>=18.19 or Node.js>=20.6 to work.

Set the NODE_OPTIONS environment variable to --import dd-trace/register.js -r dd-trace/ci/init. Run your tests as you normally would, specifying the environment where the tests are run in the DD_ENV environment variable. For example, set DD_ENV to local when running tests on a developer workstation, or ci when running them on a CI provider:

NODE_OPTIONS="--import dd-trace/register.js -r dd-trace/ci/init" DD_ENV=ci DD_SERVICE=my-javascript-app yarn test

Note: If you set a value for NODE_OPTIONS, make sure it does not overwrite --import dd-trace/register.js -r dd-trace/ci/init. This can be done using the ${NODE_OPTIONS:-} clause:

package.json

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

Adding custom tags or measures to tests

Not supported.

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
    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.

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

Datadog은 Git 정보를 사용하여 테스트 결과를 시각화하고 리포지토리, 브랜치, 커밋별로 그룹화합니다. Git 메타데이터는 CI 공급자 환경 변수와 프로젝트 경로의 로컬 .git 폴더(사용 가능한 경우)에서 테스트 계측으로 자동 수집합니다.

지원되지 않는 CI 공급자이거나 .git 폴더가 없는 상태에서 테스트를 실행하는 경우, 환경 변수를 사용하여 Git 정보를 수동으로 설정할 수 있습니다. 해당 환경 변수는 자동 탐지된 정보보다 우선합니다. 다음 환경 변수를 설정하여 Git 정보를 제공합니다.

DD_GIT_REPOSITORY_URL
코드가 저장된 리포지토리 URL입니다. HTTP, SSH URL이 모두 지원됩니다.
예시: git@github.com:MyCompany/MyApp.git, https://github.com/MyCompany/MyApp.git
DD_GIT_BRANCH
테스트 중인 Git 브랜치입니다. 대신 태그 정보를 제공하는 경우 비워 둡니다.
예시: develop
DD_GIT_TAG
테스트 중인 Git 태그입니다(해당되는 경우). 대신 브랜치 정보를 제공하는 경우 비워 둡니다.
예시: 1.0.1
DD_GIT_COMMIT_SHA
전체 커밋 해시입니다.
예시: a18ebf361cc831f5535e58ec4fae04ffd98d8152
DD_GIT_COMMIT_MESSAGE
커밋 메시지입니다.
예시: Set release number
DD_GIT_COMMIT_AUTHOR_NAME
커밋 작성자 이름입니다.
예시: John Smith
DD_GIT_COMMIT_AUTHOR_EMAIL
커밋 작성자 이메일입니다.
예시: john@example.com
DD_GIT_COMMIT_AUTHOR_DATE
ISO 8601 형식의 커밋 작성자 날짜입니다.
예시: 2021-03-12T16:00:28Z
DD_GIT_COMMIT_COMMITTER_NAME
커밋 커미터 이름입니다.
예시: Jane Smith
DD_GIT_COMMIT_COMMITTER_EMAIL
커밋 커미터 이메일입니다.
예시: jane@example.com
DD_GIT_COMMIT_COMMITTER_DATE
ISO 8601 형식의 커밋 커미터 날짜입니다.
예시: 2021-03-12T16:00:28Z

Manual testing API

Note: The manual testing API is available starting in dd-trace versions 5.23.0 and 4.47.0.

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_ENV=ci DD_SERVICE=my-custom-framework-tests yarn run-my-test-framework

Known limitations

ES modules

Mocha >=9.0.0 uses an ESM-first approach to load test files. That means that if ES modules are used (for example, by defining test files with the .mjs extension), the instrumentation is limited. Tests are detected, but there isn’t visibility into your test. For more information about ES modules, see the Node.js documentation.

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.

Further reading