Lambda Hooks for Automation Testing
TestMu AI offers a set of hooks (Lambda Hooks) that you can use to modify your automation test cases and perform multiple operations in your automation scripts — set the test status, verify downloaded files, throttle the network, capture screenshots, and more.
Hooks are grouped into three categories so you can quickly find what applies to your framework:
- Common Lambda Hooks — capabilities available in both Selenium and Playwright sessions
- Selenium-only Lambda Hooks — available only via the Selenium JavascriptExecutor
- Playwright-only Lambda Hooks — available only in Playwright (and other CDP-based) sessions
How Lambda Hooks are invoked
The invocation syntax differs by framework.
Selenium — pass the hook as a string to the JavascriptExecutor:
((JavascriptExecutor) driver).executeScript("lambda-status=passed");
Some Selenium hooks (AutoHeal, Lighthouse, accessibility scan) instead take a JSON payload via the lambdatest_executor form:
driver.executeScript("lambdatest_executor:{\"action\":\"lambda-heal-start\"}");
Playwright — pass a lambdatest_action JSON payload as the argument of an (empty) page.evaluate call:
await page.evaluate(_ => {}, `lambdatest_action: ${JSON.stringify({ action: 'setTestStatus', arguments: { status: 'passed', remark: 'Title matched' } })}`);
Common Lambda Hooks (Selenium & Playwright)
These capabilities are available in both frameworks. Note that the hook name and syntax differ per framework — use the form shown for your framework.
| Hook | Selenium | Playwright | Description |
|---|---|---|---|
| lambda-status | driver.executeScript("lambda-status=passed");Supported values: passed, failed, skipped, ignored, unknown, error | Use the setTestStatus action (also supports a remark shown on the dashboard):await page.evaluate(_ => {}, 'lambdatest_action: {"action": "setTestStatus", "arguments": {"status": "passed", "remark": "Title matched"}}'); | Mark the test passed / failed (also skipped, ignored, unknown, error). |
| lambda-testCase-start / lambda-testCase-end | driver.executeScript("lambda-testCase-start=login flow");// ...test steps...driver.executeScript("lambda-testCase-end=login flow"); | await page.evaluate(_ => {}, 'lambdatest_action: {"action": "lambda-testCase-start", "arguments": {"name": "login flow"}}');// ...test steps...await page.evaluate(_ => {}, 'lambdatest_action: {"action": "lambda-testCase-end", "arguments": {"name": "login flow"}}'); | Group commands into test cases (annotations in the command-logs view). |
| lambdaUpdateName | driver.executeScript("lambdaUpdateName=TestName"); | await page.evaluate(_ => {}, 'lambdatest_action: {"action": "lambdaUpdateName", "arguments": {"name": "TestName"}}'); | Update the test name during execution. |
| lambda-unbound-ping | driver.executeScript("lambda-unbound-ping=lambdatest.com"); | Use the lambda-unbound-ping action via the lambdatest_action pattern. | Fetch IPs from the outbound domain. |
| lighthouseReport | driver.executeScript("lambdatest_executor:{\"action\":\"lighthouseReport\"}");Lighthouse reports are also generated automatically on navigation when the performance capability is enabled. | await page.evaluate(_ => {}, 'lambdatest_action: {"action": "lighthouseReport"}'); | Generate a Lighthouse performance report. |
| lambda-accessibility-scan | driver.executeScript("lambdatest_executor:{\"action\":\"lambda-accessibility-scan\"}"); | Use the lambda-accessibility-scan action via the lambdatest_action pattern. | Run an accessibility scan. |
Selenium-only Lambda Hooks
These hooks work only through the Selenium JavascriptExecutor and are not available in Playwright sessions.
| Hook | Description | Example |
|---|---|---|
| lambda-file-exists | Check whether the downloaded file exists in the test machine. | ((JavascriptExecutor) driver).executeScript("lambda-file-exists=file-name.file_format"); |
| lambda-file-stats | Retrieve file metadata such as md5 code, modified time, name and size. | ((JavascriptExecutor) driver).executeScript("lambda-file-stats=file-name.file_format"); |
| lambda-file-content | Download file content using base64 encoding. | ((JavascriptExecutor) driver).executeScript("lambda-file-content=file-name.file_format"); |
| lambda-file-list | List down the file in download directory. | print driver.execute_script("lambda-file-list={match string with filename}");ie:print driver.execute_script("lambda-file-list=sample");Response: List of files in downloads dir starting with sample |
| lambda-files-delete | Deletes the file in the download directory in the virtual machines (VMs). | driver.executeScript("lambda-files-delete=file1.csv,file2.csv); |
| lambda-name | For changing the test name. | ((JavascriptExecutor) driver).executeScript("lambda-name=TestName");((JavascriptExecutor) driver).executeScript("lambda-name=" + "name from hooks"); |
| lambda-build | For updating the build name. | executeScript("lambda-build=BUILD_NAME"); |
| lambda-action | Used to mark a test as passed/failed. Moreover, it allows the option to include a failure reason, which will be visible on the TestMu AI Automation Dashboard inside the session view. | Map<String, String> action = new HashMap();action.put("status", "failed"); action.put("reason", "tmp reason"); driver.executeScript("lambda-action", action);((JavascriptExecutor) driver).executeScript("lambda-action=" + "Lambda Error"); |
| lambda-perform-keyboard-events | You can simulate keyboard shortcuts like ctrl + c, ctrl + v in automation test scenarios. This hook is supported on both Windows and MacOS. | js.executeScript("lambda-perform-keyboard-events:tab"); |
| lambda-breakpoint | Aborts the test execution to use the live interaction feature. | driver.executeScript("lambda-breakpoint=true"); |
| lambda-screenshot | Captures the async screenshot during test execution. | driver.executeScript("lambda-screenshot=true"); |
| lambda-throttle-network | Throttles network speed during test execution. | executeScript("lambda-throttle-network","Regular 4G") |
| lambda-ping | Fetches the IPs of the domain. | driver.executeScript("lambda-ping=lambdatest.com"); |
| lambda-exceptions | Uploads the exceptions for tests that are captured on the console. | driver.executeScript('lambda-exceptions', [[message]]) |
| lambda-get-clipboard | Prints the clipboard data on the console. | driver.executeScript("lambda-get-clipboard"); |
| lambda-set-clipboard | Sets the clipboard data. | driver.executeScript("lambda-set-clipboard= Amit"); |
| lambda-clear-clipboard | Clears the data of the clipboard. | driver.executeScript("lambda-clear-clipboard"); |
| lambda:network | Fetches the network log entries in array format during session. | driver.execute_script("lambda:network");- Fetch the network log from last fetch request time to current time.driver.execute_script("lambda:network=all");- Fetch from start of test session to current time. |
| lambda-test-tags | Dynamically update your test tags for a test session which can be used to organize and filter your test results. | Syntax : driver.executeScript("lambda-test-tags", "Tag 1,Tag 3,Tag 2");Limitations : 1. Maximum Character Length per Tag: Each tag can have up to 50 characters. 2. Maximum Number of Tags: A maximum of 15 tags can be assigned to a single test session. |
| lambda-heal-start / lambda-heal-stop | Enables / disables AutoHeal for the portion of the test between the two calls, so locator failures are healed automatically. | driver.execute_script('lambdatest_executor:{"action":"lambda-heal-start"}')// ...steps with dynamic locators...driver.execute_script('lambdatest_executor:{"action":"lambda-heal-stop"}') |
Playwright-only Lambda Hooks
These hooks are available only in Playwright (and other CDP-based) sessions, using the lambdatest_action pattern.
| Hook | Description |
|---|---|
| getTestDetails | Returns details of the running test, such as the test ID and session information.await page.evaluate(_ => {}, 'lambdatest_action: {"action": "getTestDetails"}'); |
| lambdaSetBrowserPosition | Sets the browser window position (useful when running multiple browser windows in a single session). |
Note: These hooks only work if you are connected to your TestMu AI Hub URL. If you use these hooks on any other platform, you might see the error:
javascript error: Invalid left-hand side in assignment
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