Selenium Test Automation Flashcards

Question 1

What is Selenium WebDriver and what role does it play in browser automation?

Accepted Answer

Selenium WebDriver is an interface that lets test code control a real web browser by sending commands such as opening a URL, clicking an element, or reading text. Each browser has its own driver program that receives these commands over a protocol and carries them out.

Question 2

Which component translates WebDriver commands into actions inside a specific browser?

Accepted Answer

A browser driver, such as ChromeDriver for Chrome or geckodriver for Firefox, translates WebDriver commands into actions the browser understands. The test script talks to the driver, and the driver talks to the browser. Recent Selenium versions can also manage driver binaries automatically through Selenium Manager, which locates or downloads a matching driver.

Question 3

What is a WebDriver session and why must tests close it?

Accepted Answer

A WebDriver session is the connection created when a test starts a browser, and it holds the browser state that commands act upon. Tests should call quit at the end, which closes all windows and ends the driver process. Calling only close shuts one window and can leave the driver running.

Question 4

What does the get method do, and how does it differ from clicking a link?

Accepted Answer

The get method tells the browser to load a given URL directly, replacing the current page and waiting for it to finish loading before returning. Clicking a link is an interaction with an element on the page, which may navigate as a side effect. Using get is usually faster for setup.

Question 5

Which programming languages have official Selenium bindings that teams commonly use?

Accepted Answer

Selenium offers official language bindings for Java, Python, C#, Ruby, and JavaScript, and teams usually choose the language their developers already know. The commands are similar across bindings because they all follow the W3C WebDriver standard. Learning the concepts once makes it easier to switch languages later.

Question 6

What is the W3C WebDriver standard and why does it matter?

Accepted Answer

The W3C WebDriver standard is a published specification that defines how test code and browser drivers exchange commands and responses. Because major browser vendors implement the same protocol, a test written against the standard can run across several browsers with only the driver changed.

Question 7

What is a WebElement, and what can a test do with one?

Accepted Answer

A WebElement is the object a test receives after finding an element on the page, such as a button, text field, or heading. Through it, the test can read text, read attributes, check visibility, click, or type keys. If the page re-renders, the reference can become stale.

Question 8

What is the difference between getting text and getting an attribute from an element?

Accepted Answer

The text method returns the visible text rendered for an element, which is what a user would read on screen. An attribute is a value defined in the HTML markup, such as href, value, or class, and retrieving it returns that markup value. Choose the method that matches what your check needs.

Question 9

What is a locator in Selenium and what is it used for?

Accepted Answer

A locator is a query that identifies one or more elements on a page, using a strategy such as an element ID, a CSS selector, or an XPath expression. Tests pass a locator to the find methods to obtain WebElement objects they can act on.

Question 10

Why are ID locators usually preferred when an element has a unique ID?

Accepted Answer

ID locators are usually the fastest and most readable choice because an ID should be unique within a page, so the lookup returns exactly one element. However, IDs generated dynamically, such as IDs with random numbers, change between page loads and should be avoided.

Question 11

What is the difference between a CSS selector and an XPath expression as locator strategies?

Accepted Answer

CSS selectors match elements by tag, class, ID, and attributes using a compact syntax that most front-end developers already know. XPath expressions navigate the document tree in any direction, including moving up to parent elements, and can match on text content. The choice depends on readability, speed, and the structure of the page.

Question 12

Why are long absolute XPath expressions considered fragile?

Accepted Answer

An absolute XPath starts at the root of the document and lists every step down to the target, so any change to the page structure, such as an added wrapper div, breaks the locator. Relative locators that focus on a meaningful attribute or label survive layout changes much better.

Question 13

What does find elements return that find element does not?

Accepted Answer

The singular find method returns the first matching WebElement and raises an error if nothing matches. The plural find method returns a list of all matching elements, and an empty list when nothing matches, which makes it useful for counting items or checking absence.

Question 14

How can a test confirm an element is absent without throwing an error?

Accepted Answer

A test can call the plural find method and check whether the returned list is empty, which avoids an exception when the element is expected to be missing. Another approach is to wait until the element is no longer present, which is usually better when the element should disappear after an action.

Question 15

What makes an index-based locator risky in automated tests?

Accepted Answer

An index-based locator selects an element by its position, such as the third item in a list. If products are sorted, filtered, or added, the same index can point to a different element, and the test may pass or fail for the wrong reason. Locate items by a stable name or data attribute instead.

Question 16

What is a data attribute and why do test authors ask developers to add them?

Accepted Answer

A data attribute is a custom HTML attribute whose name begins with data- followed by a label, used to store values that scripts or tests can read without changing how the page looks. Test authors ask for data attributes, such as data-testid, so locators stay stable when styling or wording changes.

Question 17

Why do browser tests often fail because of timing rather than real defects?

Accepted Answer

Pages load and update asynchronously, so a script can try to interact with an element before it exists, is visible, or is enabled. The test then fails even though the application is working correctly. Waits give the script a controlled way to pause until the page reaches the state the next step needs.

Question 18

What is an implicit wait and how does it apply to element lookups?

Accepted Answer

An implicit wait is a session-wide setting that tells the driver to keep retrying a find call for up to a set time before raising an error. It applies to every element lookup made during the session. Because it is global, it can slow failure reporting and combine poorly with explicit waits.

Question 19

What is an explicit wait and when should a test use one?

Accepted Answer

An explicit wait pauses the test until a specific condition is true for a specific element, such as becoming clickable or becoming visible, or until a time limit expires. Tests should use explicit waits at points where the page is expected to change.

Question 20

What is the purpose of an expected condition in an explicit wait?

Accepted Answer

An expected condition is a reusable check that returns a true or false result about the page, such as whether an element is present, visible, or clickable. The wait repeatedly evaluates that check until it succeeds or the timeout expires. A precise condition is better than a fixed pause.

Question 21

Why are fixed sleep calls considered a poor synchronization strategy?

Accepted Answer

A fixed sleep pauses the test for a set number of seconds whether or not the page is ready. If the page loads quickly, time is wasted, and if it loads slowly, the test still fails. Sleeps make suites slow and flaky, so explicit waits that respond to page state are preferred.

Question 22

How does a wait for visibility differ from a wait for presence?

Accepted Answer

A presence wait succeeds when the element exists in the page's structure, even if it is hidden. A visibility wait also requires the element to be displayed with nonzero size. Since hidden elements cannot be clicked, a visibility wait is usually the right choice before interacting with a control.

Question 23

What is a stale element reference and how can a test recover from it?

Accepted Answer

A stale element reference occurs when the page reloads or re-renders after a WebElement was found, so the stored reference no longer points to a live element. The usual recovery is to locate the element again after the page has settled, often by wrapping the lookup in a wait.

Question 24

What is a timeout in a wait, and why should it be chosen carefully?

Accepted Answer

A timeout is the maximum time a wait keeps checking a condition before it fails the test. If it is too short, tests fail on slow but correct pages, and if it is very long, real failures take a long time to report. A balanced value keeps feedback quick.

Question 25

What are the basic element interaction methods in Selenium?

Accepted Answer

The core interaction methods include click to activate a button or link, send keys to type into a text field, clear to remove existing text, and submit to send a form. Each method acts on a WebElement that the test has already located.

Question 26

What is the difference between clicking an element and sending keys to it?

Accepted Answer

Clicking simulates a mouse press on the element, which can trigger a button action, follow a link, or select an option. Sending keys simulates typing characters into an element that accepts text input, such as a field or text area. Use the method that matches the user action being tested.

Question 27

How do you select an option from a dropdown element in Selenium?

Accepted Answer

For native HTML select elements, Selenium provides a Select helper class that can choose an option by visible text, value, or index. For custom dropdowns built from divs, the test must click the control to open it and then click the option, because the helper works only with native select elements.

Question 28

How does a test move between windows or tabs in Selenium?

Accepted Answer

Each window or tab has a handle, which is a string identifier. The test can list all handles, then switch to the desired one before interacting with its content, since the driver acts only on the current window. After finishing, the test should switch back to the original handle.

Question 29

How can a test handle a JavaScript alert?

Accepted Answer

Selenium provides an alert interface that the test switches to while an alert is open. The test can then read its text, accept it, dismiss it, or type into a prompt. Unhandled alerts usually cause later commands to fail, so handle them promptly.

Question 30

How can a test upload a file through a standard file input in Selenium?

Accepted Answer

For a standard file input element, the test can call send keys on that element with the absolute path to the file, which fills the input without opening the operating system dialog. Custom upload widgets often hide the real input, which must be located directly.

Question 31

What do checks on the page title and current URL verify?

Accepted Answer

Title and URL checks confirm that navigation reached the expected destination after an action. The title shows the document's title, while the current URL shows the address, including the path and query parameters. Asserting both gives a quick signal about where the user landed.

Question 32

How does a test handle an iframe before it can interact with elements inside it?

Accepted Answer

Elements inside an iframe belong to a separate document, so the test must switch into the frame first, either by index, by name or ID, or by a located frame element. After finishing inside the frame, the test switches back to the default content to reach elements on the main page.

Question 33

Why is test isolation important in browser automation?

Accepted Answer

Isolated tests do not depend on the results or leftover state of other tests, so any test can run alone or in any order. Shared cookies, logged-in sessions, or data left behind can make one test pass only when another runs first. Clean sessions keep failures easy to reproduce.

Question 34

What is the page object pattern in Selenium test design?

Accepted Answer

The page object pattern places locators and page actions in a class that represents one page or component, so tests call meaningful methods such as login rather than repeating raw element lookups. When the page changes, the fix goes in one class instead of every test that uses it.

Question 35

Why do teams keep assertions in test methods rather than inside page objects?

Accepted Answer

Page objects describe how to interact with a page, while tests decide what the expected outcome is. Keeping assertions in tests makes each test's purpose visible and lets the same page method serve checks with different expectations. Hiding assertions in page objects can make failures harder to trace.

Question 36

How do you structure a data-driven test in Selenium?

Accepted Answer

A data-driven test runs the same steps repeatedly with different input values, such as several usernames and passwords for a login form. The values are kept in a separate source like a spreadsheet, CSV file, or list in code. This separation lets testers add cases without changing the automation logic.

Question 37

What is the purpose of a configuration file in a Selenium project?

Accepted Answer

Configuration files hold settings that change between environments, such as base URLs, browser choices, timeouts, and credentials for test accounts. Sensitive values such as passwords should come from environment variables or a secrets store rather than being committed to the repository.

Question 38

How can a test take a screenshot to help diagnose a failure?

Accepted Answer

WebDriver can capture an image of the current browser window, which is useful when a failure report needs visual context. Many teams take a screenshot automatically in a failure handler so that every failed test leaves evidence behind. Screenshots show what the user saw but not hidden state.

Question 39

How do teams commonly run Selenium tests in an automated build pipeline?

Accepted Answer

Teams usually configure the pipeline to start a suite on every change, run the browsers in headless mode where no window appears, and collect reports and screenshots as build artifacts. Tests often run in parallel across several machines or containers to reduce total time.

Question 40

What makes flaky tests harmful, and how should a team respond to them?

Accepted Answer

A flaky test passes and fails on the same code without any change, which erodes trust in the suite and teaches people to ignore failures. Teams should investigate the cause, which is often a timing problem, a shared state issue, or an unstable locator, and fix it rather than rerunning until it passes.

Selenium Test Automation Flashcards

1WebDriver fundamentals

2Locating page elements

3Waits and synchronization

4Interacting with page features

5Test design and maintenance

Learning Resources