Working with client test runners

  • Release version: Australia
  • Updated June 16, 2026
  • 4 minutes to read
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    Summary of Working with client test runners

    Client test runners in ServiceNow allow automated tests that interact with forms or user interface (UI) elements to execute within a browser tab or window. The Automated Test Framework (ATF) supports two types:Client Test Runnersfor manually started tests andScheduled Client Test Runnersfor tests executed on a schedule. These runners execute tests as the logged-in user and show test activity in the Execution Frame.

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    Key Features

    • Test Execution Control: The test execution property must be enabled to use client test runners. This property is disabled by default to protect production environments from unintended test runs. Tests should run only on development, test, or non-production instances.
    • Execution and Debugging Views: When additional debugging is enabled, the client test runner shows both Execution Frame and Debug Info tabs. Execution Frame displays normal test progress and captures screenshots saved to test results.
    • Browser Recommendations: Some browsers (Internet Explorer, Edge, older Firefox versions) need periodic restarting due to memory limitations. The client test runner should run in its own window, remain partially visible, and the screen should not be locked to ensure proper execution and screenshot capture. The zoom level should be set at 100% for optimal screenshot quality.
    • Scheduled Suites: For scheduled test suites, especially on macOS with Chrome or Safari, the screen must remain unlocked and the test runner tab visible to avoid slow execution or timeouts. Running scheduled client test runners in a virtual machine without screen locking is recommended.
    • JavaScript Window Command Handling: The client test runner intercepts window commands such as console logs, alerts, confirms, and prompts, automatically responding with default values (e.g., true for confirm and "test value" for prompt) to enable uninterrupted test execution.
    • Active Test Runners Monitoring: Active client test runners are registered in the Active Test Runners table, accessible via modules filtered for manual or scheduled runners. This allows monitoring of runner status and browser details used for scheduled test executions. The system marks runners inactive if they fail to check in on time and eventually removes them.

    Practical Considerations for ServiceNow Customers

    • Always enable test execution only in safe environments to prevent data corruption or outages.
    • Use the client test runner module to manually start and monitor tests, or configure scheduled suites with appropriate browser criteria.
    • Ensure the client test runner window remains visible and the screen active during test runs to avoid delays or failures.
    • Leverage the Active Test Runners modules to track running tests and diagnose issues related to scheduled executions.

    If an automated test includes steps that involve a form or any other user-interface (UI) element, it runs those steps in a browser tab or window called a test runner or client test runner.

    The Automated Test Framework supports two types of client test runners: Client Test Runners for manually started tests and Scheduled Client Test Runners for tests started by a schedule.

    When test execution is enabled, clicking the Client Test Runner module opens the client test runner in the current browser session. If tests are waiting to be run, the Client Test Runner runs a waiting test. If no test is running, the message Waiting for a test to run displays in the client test runner.

    While the client test runner is idle, it checks every five seconds for waiting tests to start. This ensures that the system runs any tests it may have been unable to start because no client with the proper configuration was available.
    Note:
    The client test runner monitors for tests from the current session and runs those tests as the logged-in user (unless it executes an Impersonate User step). If you start a client test runner, log out from the current session, and then log in again, the client test runner executes using the new session.

    When the client runner is active, it displays the activity of the currently running test in the Execution Frame.

    Note:
    You are now allowed to execute multiple tests at a given time.

    Test execution property

    To work with the client test runner module, the test execution property must be enabled.
    Note:
    By default, the system property that is used to run automated tests is disabled to prevent you from accidentally running these tests on a production system. To avoid data corruption or an outage, run tests only on development, test, and other non-production instances.

    If the test execution property is disabled when you select this module, the system displays a message and a link to the automated test framework properties page where you can enable it.

    Additional debugging functionality

    If you have enabled additional debugging functionality, the client test runner module displays two tabs: Execution Frame and Debug Info. The Execution Frame displays the information normally shown by the client test runner and the Debug Info displays additional debugging information.

    The system takes screen shots from the tests in the Execution Frame tab and records them to the test result record.

    Browser recommendations for all tests and suites

    • Some browsers have memory-management limitations that make it necessary to occasionally close and restart the browser when running the client test runner. These browsers include Internet Explorer, Edge, and older versions of Firefox. How often you should close the browser depends on the memory allocation in the browser application.
    • Some browsers have features that throttle CPU time. To avoid problems, follow these guidelines:
      • Run the client test runner in its own browser window.
      • Keep the client test runner at least partially visible on the screen.
      • Make certain the screen is not locked or shut off.
    • The client test runner takes screen shots as the tests run. For best results with screen shots, leave the browser zoom level set to 100%.

    Browser recommendations for scheduled suites

    The client test runners for scheduled suites have additional browser requirements.

    • On OS X with the client test runner on Chrome or Safari: If the screen is locked or the client test runner tab is not shown, when the system attempts to run the test suite, tests run significantly slower and may time out. For best performance, run client test runners for scheduled suites in a virtual machine (VM) environment in which the screen does not become locked or disabled.
    • The browser must meet the criteria you specified on the Scheduled suite run record.
    • A client test runner meeting the criteria you specified on the Scheduled suite run record must be available to run the test suite at the scheduled time. The system cannot automatically open a client test-runner session.

    Javascript window command intercepts

    The Client Test Runner captures window object commands including console.log, console.error, alert, confirm, and prompt, with default responses where necessary.

    • Any script that calls window.confirm receives a boolean response of true.
    • Any script that calls window.prompt receives the string response test value.
    • Any script call to alert is ignored.

    Active Test Runners table

    When you start a client test runner, the system registers that runner in the Active Test Runners table. You can view this table in the Active Manual Test Runners module and the Active Scheduled Test Runners module. These two modules provide views of the same table, filtered to show only manual or only scheduled test runners.

    The Active Scheduled Test Runner module is useful when you create a scheduled suite run. For scheduled suite runs, you can specify the browser to use. To determine the name and version of a browser you want to use, start a scheduled test runner with that browser, then inspect that runner's record in the Active Scheduled Test Runners module.

    The data in this table is transient. While the runner is active, it reports in to the system at a specified interval. If the runner does not report in at the expected time, the system marks the runner as inactive. After a period of time the system deletes the runner. You can modify these intervals on the Automated Test Framework properties page.