How to Fix Element Selectors in Wolfpack?

1 - How Wolfpack Interacts with Web Page Elements

A - General Principles

Wolfpack is designed to simplify and automate end-to-end testing. To identify and interact with web page elements, Wolfpack uses selectors, which are strings that pinpoint a specific element in the DOM (Document Object Model).

Selectors are crucial for ensuring automated tests are reproducible and robust. However, they can become fragile if the targeted elements change in the web application, particularly due to code updates or dynamic variations.

Wolfpack primarily uses two types of selectors: CSS selectors and XPath selectors. These selectors are automatically generated by the recorder but can be manually adjusted if necessary.

B - CSS Selectors

CSS selectors are based on the CSS language syntax and allow targeting of elements using their classes, IDs, tags, attributes, or combinations of these criteria.

Examples of CSS Selectors:

• #submit-button: Selects an element with the ID “submit-button”.
• .form-input: Selects all elements with the class “form-input”.
• div.container > ul > li:first-child: Targets the first item in a list within a “div” element with the class “container”.

Advantages:

• Simple and readable.
• Fast to execute as they are well-optimized by modern browsers.
• Broad compatibility with standard elements.

Limitations:

• Can become fragile if classes or IDs change dynamically.
• Less suitable for targeting complex elements in a deep DOM structure.

C - XPath Selectors

XPath (XML Path Language) is a more expressive and powerful syntax that allows navigation through the DOM hierarchy. Unlike CSS selectors, it can target elements based on their attributes or text content.

Examples of XPath Selectors:

• //button[@id='submit-button']: Selects a button with the ID “submit-button”.
• //div[contains(@class, 'error-message')]: Targets a “div” element containing the class “error-message”.
• //a[text()='Learn more']: Finds a link with the text “Learn more”.

Advantages:

• Ability to target complex or inaccessible elements via CSS selectors.
• Flexible for dynamic content.

Limitations:

• Less readable.

2 - My Test Fails Because an Element Is Not Found on the Page, What Should I Do?

When a test fails because an element cannot be found, it’s essential to diagnose the problem and fix the relevant selector. Here are the steps to follow:

A - Wolfpack Saves Multiple Selectors for Each Action

Whenever an action is recorded, Wolfpack generates at least two or three selectors to identify the element. These selectors typically include a mix of CSS and XPath. If one selector doesn’t work, simply try using another one from the available options. This might resolve the issue without needing further adjustments.

To view and modify the selectors, open the test in the scenario editor and examine the suggested options for the relevant action.

B - Is This Action Really Essential for the Test?

Wolfpack records all user interactions during the session. However, not all actions are essential to validate a test scenario. Ask yourself:

• Is this interaction crucial for the test?
• Can it be omitted without compromising the main objective?

Example: Clicking on a blank area of the page to trigger a focus loss might not be relevant to the primary scenario. Removing this action could resolve the error.

C - Is the Element Targeted by the Selector Still Present on the Page?

With modern frameworks like React, Angular, or Vue, the classes and IDs of elements can be dynamically generated. This means an element might:

• Not be rendered at a specific moment.
• Have a different class or ID with each execution.
• Be hidden or removed from the DOM due to rendering conditions.

Solution: Use more generic selectors or those based on stable attributes (like data-testid) to target the elements.

D - Simplify the Selector

Selectors automatically generated by the recorder can sometimes be overly precise. They may include a combination of classes or complicated paths within the DOM. Simplifying the selector can increase its robustness.

Example:

Generated Selector:

form > div:nth-child(3) > button.btn-primary.btn-lg

Simplified Selector:

button.btn-primary

The simplified selector is less sensitive to structural changes in the DOM while remaining functional.

E - Use the Browser Inspector to Locate the Element

Browser development tools make it easy to retrieve XPath or CSS selectors. To do this:

• Access the developer tools via F12 or right-click > “Inspect”.
• Select the element to target on the page, either directly in the displayed code or by right-clicking on the element and choosing “Inspect”.
• On the targeted element in the code, right-click > copy > selector or XPath.

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Tip: Test your selectors with document.querySelector (CSS) or document.evaluate (XPath) to validate their functionality before adding them to the test.

F - Is the Element Really Identifiable?

Some elements lack unique or stable attributes, making them hard to identify. In this case:

• Look for parent or ancestor elements with stable attributes to construct a combined selector.
• If possible, ask the development team to add data-* attributes to facilitate identification.

Example:

Suppose a button has no ID or class but is located within a unique container:

//div[@id='unique-container']//button[text()='Submit']

This selector uses the container to indirectly target the button.

Conclusion

Fixing selectors is an essential skill for ensuring the stability of end-to-end tests in Wolfpack. By following these steps, you can diagnose the cause of errors, simplify your selectors, and create more robust tests. Remember, the main goal is to maximize the relevance and reliability of your scenarios while minimizing maintenance efforts.

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