Extended Debugging Options for Selenium Testing

LambdaTest's Extended Debugging Options provide powerful capabilities to debug and optimize your Selenium tests by giving you granular control over network behavior and system performance. These advanced debugging features allow you to intercept and modify network requests, simulate various CPU and network conditions, and download comprehensive network analysis files—all within your test automation workflow.

With Extended Debugging Options, you can replicate real-world scenarios such as slow networks, resource-constrained devices, API failures, and connectivity issues, ensuring your application delivers a robust user experience across diverse conditions and environments.

How can Extended Debugging Options help you?

Extended Debugging Options on LambdaTest provide comprehensive capabilities for advanced testing and debugging scenarios:

Network Request Control: Intercept and modify outgoing requests to test API failures, redirects, and mock responses without setting up complex backend infrastructure.
Performance Testing: Simulate various CPU and network throttling conditions to understand how your application performs on low-end devices or poor network connections.
Network Analysis: Download HAR (HTTP Archive) files to perform detailed analysis of network traffic, load times, and resource optimization.
Realistic Test Scenarios: Create test conditions that mirror real-world user experiences, including offline modes, slow connections, and server errors.

Available Extended Debugging Methods

LambdaTest supports the following extended debugging methods:

Method	Description
`lt:intercept:redirect`	Redirect network requests to different URLs
`lt:intercept:response`	Mock responses for intercepted requests
`lt:intercept:error`	Simulate error responses for requests
`lt:throttle:cpu`	Simulate different CPU performance levels
`lambda-throttle-network`	Configure and simulate network conditions
`lt:downloadHAR`	Download HTTP Archive files for analysis

1. Intercept Network Requests

LambdaTest provides three specialized methods to intercept and modify network requests, enabling you to test how your application behaves under different network conditions, mock API responses, and simulate error scenarios.

Method 1: Redirect Requests (`lt:intercept:redirect`)

Redirect outgoing requests to a different URL using the lt:intercept:redirect command.

Parameters

Parameter	Type	Required	Description
`url`	String	Yes	URL pattern to intercept.
`redirectUrl`	String	Yes	Target URL to redirect the request to.

Example Usage

Python:

driver.execute_script("lt:intercept:redirect", {
    "url": "https://www.google.com",
    "redirectUrl": "https://www.bing.com"
})
driver.get("https://www.google.com")

Node.js:

await driver.executeScript("lt:intercept:redirect", {
    url: "https://www.google.com",
    redirectUrl: "https://www.bing.com"
});
await driver.get("https://www.google.com");

Response:

{
    "status": "success",
    "message": "Requests to 'https://www.google.com' will be redirected to 'https://www.bing.com'"
}

Method 2: Mock Response (`lt:intercept:response`)

Mock a custom response for the intercepted URL using the lt:intercept:response command.

Parameters

Parameter	Type	Required	Description
`url`	String	Yes	URL pattern to intercept.
`response`	Object	Yes	Response object containing status, headers, and body.
`response.status`	Integer	No	HTTP status code (default: 200).
`response.headers`	Object	No	Custom response headers as key-value pairs.
`response.body`	String	No	Response body content (use JSON string for JSON responses).

Example Usage

Python:

driver.execute_script("lt:intercept:response", {
    "url": "https://www.amazon.com",
    "response": {
        "status": 200,
        "headers": {
            "Content-Type": "application/json",
            "keyheader": "valueheader"
        },
        "body": "{\"keybody\":\"valuebody\"}"
    }
})
driver.get("https://www.amazon.com")

Node.js:

await driver.executeScript("lt:intercept:response", {
    url: "https://jsonplaceholder.typicode.com/todos/1",
    response: {
        status: 200,
        headers: {
            "Content-Type": "application/json"
        },
        body: JSON.stringify({
            id: 999,
            title: "Custom mocked response",
            completed: true
        })
    }
});
await driver.get("https://jsonplaceholder.typicode.com/todos/1");

Response:

{
    "status": "success",
    "message": "Mock response configured for the specified URL"
}

Method 3: Simulate Error Response (`lt:intercept:error`)

Inject error responses to test how your application handles failures using the lt:intercept:error command.

Parameters

Parameter	Type	Required	Description
`url`	String	Yes	URL pattern to intercept.
`error`	String	Yes	Error type to simulate. See supported error types below.

Example Usage

Python:

driver.execute_script("lt:intercept:error", {
    "url": "https://www.lambdatest.com",
    "error": "TimedOut"
})
driver.get("https://www.lambdatest.com")

Node.js:

await driver.executeScript("lt:intercept:error", {
    url: "https://example.com/images/*",
    error: "Failed"
});
await driver.get("https://example.com/images/photo.jpg");

Response:

{
    "status": "success",
    "message": "Error 'TimedOut' configured for the specified URL"
}

Supported Error Types

Error Type	Description
`Failed`	Generic network failure
`Aborted`	Request was aborted
`TimedOut`	Request timed out
`AccessDenied`	Access to resource denied
`ConnectionClosed`	Connection closed unexpectedly
`ConnectionReset`	Connection reset by peer
`ConnectionRefused`	Connection refused by server
`ConnectionAborted`	Connection aborted
`ConnectionFailed`	Connection failed to establish
`NameNotResolved`	DNS name resolution failed
`InternetDisconnected`	Internet connection lost
`AddressUnreachable`	Network address unreachable

2. Throttle CPU Performance

The lt:throttle:cpu method simulates lower or higher CPU usage on the testing device, allowing you to measure your application's performance under resource constraints.

Parameters

Parameter	Type	Required	Description
`rate`	Integer	Yes	Rate of slowdown. Example: `2` equals 2x slowdown, `4` equals 4x slowdown.

Example Usage

Python:

driver.execute_script("lt:throttle:cpu", {"rate": 4})
driver.get("https://lambdatest.com")

Node.js:

await driver.executeScript("lt:throttle:cpu", { rate: 4 });
await driver.get("https://www.wikipedia.org");

Response:

{
    "status": "success",
    "message": "CPU throttled to 4x slowdown."
}

CPU Throttling Rates

A rate of 1 means no throttling (normal CPU performance)
A rate of 2 means 2x slower than normal
A rate of 4 means 4x slower than normal
Higher values simulate lower-end devices or heavy CPU load scenarios

3. Throttle Network Conditions

The lambda-throttle-network method enables you to simulate various network conditions including slower speeds, high latency, and offline modes. This helps ensure your application performs well across different connection types.

Parameters

Parameter	Type	Required	Description
`download`	Integer	Conditional	Download speed in kb/s (required for custom configuration).
`upload`	Integer	Conditional	Upload speed in kb/s (required for custom configuration).
`latency`	Integer	Conditional	Round Trip Time (RTT) in milliseconds (required for custom configuration).

Alternatively, you can pass a predefined network profile name as a string (e.g., "Regular 3G", "Offline").

Custom Network Configuration

Python:

driver.execute_script("lambda-throttle-network", {
    "download": 1000,
    "upload": 750,
    "latency": 20
})
driver.get("https://lambdatest.com")

Node.js:

await driver.executeScript("lambda-throttle-network", {
    download: 1000,
    upload: 500,
    latency: 40
});
await driver.get("https://www.cnn.com");

Response:

{
    "status": "success",
    "message": "Network conditions set with 1000 kb/s download, 750 kb/s upload, and 20 ms latency."
}

Using Predefined Network Profiles

Python:

driver.execute_script("lambda-throttle-network", "Offline")
driver.get("https://lambdatest.com")

Node.js:

await driver.executeScript("lambda-throttle-network", "Regular 3G");
await driver.get("https://www.nytimes.com");

Predefined Network Profiles

LambdaTest provides predefined network profiles for quick testing across common connection types:

Profile	Download Speed	Upload Speed	Latency (ms)
`offline`	0 kb/s	0 kb/s	0
`GPRS`	50 kb/s	20 kb/s	500
`Regular 2G`	250 kb/s	50 kb/s	300
`Good 2G`	450 kb/s	150 kb/s	150
`Regular 3G`	750 kb/s	250 kb/s	100
`Good 3G`	1 Mb/s	750 kb/s	40
`Regular 4G`	4 Mb/s	3 Mb/s	20
`DSL`	2 Mb/s	1 Mb/s	5
`WiFi`	30 Mb/s	15 Mb/s	2
`online`	No Restrictions	No Restrictions	No Restrictions

4. Download HAR File

The lt:downloadHAR method downloads network activity data in HAR (HTTP Archive) format, enabling detailed analysis of network performance, resource loading times, and HTTP transactions.

Parameters

Parameter	Type	Required	Description
`job_id`	String	Yes	Unique job identifier for the test session.
`output_file`	String	Yes	Filename to save the HAR file.

Example Usage

Python:

driver.execute_script("lt:downloadHAR", {
    "job_id": "123456",
    "output_file": "network.har"
})

Node.js:

await driver.executeScript("lt:downloadHAR", {
    job_id: "123456",
    output_file: "network.har"
});

Response:

{
    "status": "success",
    "message": "HAR file downloaded as 'network.har'."
}

HAR File Analysis

HAR files can be analyzed using tools like:

Chrome DevTools (Network tab → right-click → "Save all as HAR")
Online HAR analyzers
Performance monitoring tools

These files contain detailed information about request/response headers, timing data, cookies, and more.

Best Practices

When using Extended Debugging Options on LambdaTest, consider the following best practices:

Use Wildcards Wisely: When intercepting requests, use specific URL patterns to avoid unintended interceptions.
Test Incrementally: Start with mild throttling conditions and gradually increase constraints to identify performance breaking points.
Combine Methods: Use multiple methods together (e.g., network throttling + CPU throttling) to simulate realistic low-end device scenarios.
Analyze HAR Files: Download HAR files for failed tests to identify network-related issues and performance bottlenecks.

By leveraging these Extended Debugging Options, you can create comprehensive test scenarios that validate your application's behavior under diverse real-world conditions, ensuring a robust and reliable user experience.

Extended Debugging Options for Selenium Testing

How can Extended Debugging Options help you?

Available Extended Debugging Methods

1. Intercept Network Requests

Method 1: Redirect Requests (`lt:intercept:redirect`)

Parameters

Example Usage

Method 2: Mock Response (`lt:intercept:response`)

Parameters

Example Usage

Method 3: Simulate Error Response (`lt:intercept:error`)

Parameters

Example Usage

Supported Error Types

2. Throttle CPU Performance

Parameters

Example Usage

3. Throttle Network Conditions

Parameters

Custom Network Configuration

Using Predefined Network Profiles

Predefined Network Profiles

4. Download HAR File

Parameters

Example Usage

Best Practices

Test across 3000+ combinations of browsers, real devices & OS.

Help and Support

Do you find this helpful?

Still need help?

Related Articles

How can Extended Debugging Options help you?​

Available Extended Debugging Methods​

1. Intercept Network Requests​

Method 1: Redirect Requests (lt:intercept:redirect)​

Parameters​

Example Usage​

Method 2: Mock Response (lt:intercept:response)​

Parameters​

Example Usage​

Method 3: Simulate Error Response (lt:intercept:error)​

Parameters​

Example Usage​

Supported Error Types​

2. Throttle CPU Performance​

Parameters​

Example Usage​

3. Throttle Network Conditions​

Parameters​

Custom Network Configuration​

Using Predefined Network Profiles​

Predefined Network Profiles​

4. Download HAR File​

Parameters​

Example Usage​

Best Practices​

Test across 3000+ combinations of browsers, real devices & OS.

Help and Support

Do you find this helpful?

Still need help?

Related Articles

How can Extended Debugging Options help you?

Available Extended Debugging Methods

1. Intercept Network Requests

Method 1: Redirect Requests (`lt:intercept:redirect`)

Parameters

Example Usage

Method 2: Mock Response (`lt:intercept:response`)

Parameters

Example Usage

Method 3: Simulate Error Response (`lt:intercept:error`)

Parameters

Example Usage

Supported Error Types

2. Throttle CPU Performance

Parameters

Example Usage

3. Throttle Network Conditions

Parameters

Custom Network Configuration

Using Predefined Network Profiles

Predefined Network Profiles

4. Download HAR File

Parameters

Example Usage

Best Practices