20 Cypress Interview Questions and Answers

Cypress is an open source testing framework that allows developers to quickly and easily write, debug, and run tests for web applications. As the demand for web developers with Cypress experience increases, it is important to be prepared for the questions you may face during a technical interview. In this article, we review some of the most common Cypress interview questions and provide tips on how to best answer them.

Cypress Interview Questions and Answers

Here are 20 commonly asked Cypress interview questions and answers to prepare you for your interview:

1. What is Cypress?

Cypress is an open source, JavaScript-based testing framework designed for modern web applications. It provides a comprehensive set of tools and features that make it easy to create automated tests for any application. Cypress allows developers to write end-to-end tests quickly and easily, without having to rely on external services or libraries. With its intuitive API and powerful debugging capabilities, Cypress makes it simple to ensure the quality of your codebase. Additionally, Cypress has built-in support for popular frameworks such as React, Angular, and Vue.js, making it even easier to test complex applications.

2. Why should we use it for our automated testing needs?

Cypress is an excellent choice for automated testing needs due to its ease of use and comprehensive features. Cypress has a user-friendly interface that makes it easy to set up tests quickly, allowing developers to focus on writing code rather than spending time configuring test environments. Additionally, Cypress offers powerful debugging tools such as the ability to pause tests at any point in order to inspect elements or debug issues. This allows developers to easily identify problems and fix them without having to start from scratch. Furthermore, Cypress provides detailed reports with screenshots and videos of each test run, making it easier to track progress and pinpoint areas of improvement. Finally, Cypress supports multiple browsers and operating systems, ensuring compatibility across different platforms.

3. Can you explain the difference between unit tests, integration tests, and E2E tests?

Unit tests are used to test individual units of code, such as functions or classes. They focus on the smallest parts of an application and ensure that each unit works correctly in isolation from other components. Unit tests are typically written using a testing framework like Jest or Mocha.

Integration tests are used to test how different components interact with one another. These tests check for compatibility between various modules and make sure they work together properly. Integration tests can be written using Cypress or Selenium.

E2E (end-to-end) tests are used to test the entire system from start to finish. These tests simulate user interactions with the application and verify that all features are working correctly. E2E tests are usually written using Cypress or Protractor.

4. What are some advantages of using cypress over other end-to-end testing tools like Selenium WebDriver?

Cypress offers several advantages over other end-to-end testing tools like Selenium WebDriver. Firstly, Cypress is incredibly fast and efficient when it comes to running tests. It runs in the same run loop as the application being tested, meaning that tests can be executed much faster than with other tools. Additionally, Cypress has a built-in debugging tool which allows developers to quickly identify any issues or bugs within their code.

Another advantage of using Cypress is its ability to automatically wait for elements on the page to load before executing commands. This eliminates the need for manual waits and makes writing tests much easier. Furthermore, Cypress also provides an easy-to-use API which simplifies the process of writing tests. Finally, Cypress supports both unit and integration tests, making it a great choice for comprehensive end-to-end testing.

5. How does cypress compare with Puppeteer?

Cypress and Puppeteer are both popular open source automation tools used for end-to-end testing. Both have their own advantages and disadvantages, so it is important to consider the specific needs of a project before deciding which tool to use.

When comparing Cypress and Puppeteer, one key difference is that Cypress runs in the same environment as the application being tested, while Puppeteer requires an additional browser instance to be launched. This means that Cypress can detect changes made by the application more quickly than Puppeteer. Additionally, Cypress has built-in support for debugging and reporting, making it easier to identify issues during development.

Another major difference between Cypress and Puppeteer is the way they interact with the DOM. Cypress uses its own custom commands to manipulate elements on the page, while Puppeteer relies on standard JavaScript methods. This makes Cypress simpler to learn and use, but may limit its flexibility when dealing with complex scenarios.

Finally, Cypress offers better support for asynchronous operations than Puppeteer. It allows developers to write tests that wait for certain conditions to be met before continuing, making it easier to test applications that rely heavily on AJAX requests or other asynchronous operations.

6. Is it possible to run cypress test cases in parallel? If yes, then how?

Yes, it is possible to run Cypress test cases in parallel. This can be done by using the cypress-parallel plugin. The plugin allows users to split their tests into multiple processes and then execute them simultaneously. To use this plugin, users must first install it via npm or yarn. Once installed, they can configure the number of processes they want to run in parallel and specify which files should be included in each process. After that, they can simply call the “cypress run” command with the –parallel flag to start running their tests in parallel. Additionally, users can also set up a CI/CD pipeline to automatically run their tests in parallel on every commit.

7. What’s the difference between a “beforeEach” hook and a “beforeAll” hook? When would you want to use each of them?

A “beforeEach” hook is a function that runs before each test in the suite. This allows developers to set up any necessary conditions for their tests, such as creating variables or setting up spies. It’s useful when you need to reset something between tests, like clearing out a database table or resetting an API call counter.

A “beforeAll” hook is a function that runs once before all of the tests in the suite. This can be used to perform setup tasks that don’t need to be repeated for every single test, such as establishing a connection to a database or loading fixtures. It’s also useful if you want to run some code only once at the beginning of your test suite, such as logging into an application or setting up global variables.

8. When would you want to use an asynchronous callback function instead of a synchronous function?

When developing with Cypress, it is important to understand when to use an asynchronous callback function instead of a synchronous function. An asynchronous callback function should be used when the code needs to wait for something else to happen before continuing. This could include waiting for an API call to finish or for a user action to occur. Asynchronous functions allow the code to continue running while the other task completes in the background. This can help improve performance and reduce latency issues. Additionally, using asynchronous functions allows developers to write more concise code that is easier to read and debug.

9. What do you understand about fixtures in Cypress?

Fixtures in Cypress are used to store data that can be reused across multiple tests. This helps reduce the amount of time needed to set up and tear down test environments, as well as reducing the complexity of writing tests. Fixtures also help ensure consistency between tests by providing a single source of truth for all tests. Fixtures can contain any type of data, including JSON objects, HTML files, images, or even text files. They can also be used to mock API responses, allowing developers to write tests without relying on external services. By using fixtures, developers can create more reliable and maintainable tests.

10. What happens when you call cy.pause() inside a test case?

When cy.pause() is called inside a test case, Cypress will pause the execution of the test and open up the Command Log in the browser window. This allows the user to inspect the state of the application at that point in time. The user can then use the Command Log to step through each command executed so far, as well as view any errors or warnings that have been generated. Additionally, the user can also add new commands to the log while paused, allowing them to debug their tests more effectively. Once the user has finished debugging, they can resume the test by clicking the “Resume” button in the Command Log.

11. What is the purpose of cy.request() ?

The purpose of cy.request() is to make an HTTP request from within a Cypress test. It allows developers to send requests to the server and receive responses, which can then be used to validate that the application is working as expected. This helps ensure that the application is functioning correctly before it goes live. Additionally, cy.request() can be used to mock API calls in order to simulate user interactions with the application. By using cy.request(), developers can quickly and easily create tests for their applications without having to manually set up each individual request.

12. What are aliases and why are they important?

Aliases are a feature of Cypress that allow developers to assign custom names to elements in their code. This makes it easier for developers to refer to the same element multiple times throughout their code without having to remember its exact location or name. Aliases also make it easier to debug and maintain code, as they provide an easy way to identify specific elements within the codebase. Additionally, aliases can be used to group related elements together, making it simpler to manage large amounts of code. By using aliases, developers can create more organized and efficient code that is easier to read and understand.

13. What is the best way to get access to DOM elements from within a test case?

The best way to get access to DOM elements from within a test case is by using the cy.get() command. This command allows you to select an element based on its attributes, such as id, class name, or data-attribute. Once selected, Cypress will return the element and allow you to interact with it in various ways. For example, you can use the .should() command to make assertions about the element’s state, or use the .click() command to simulate user interaction. Additionally, Cypress provides several convenience methods that make it easier to work with specific types of elements, such as cy.get(‘input’) for selecting input fields.

14. What are some examples of built-in commands provided by Cypress?

Cypress provides a wide range of built-in commands that allow developers to quickly and easily automate their tests. Some examples include:

• cy.visit() – This command allows developers to navigate to any URL within the application they are testing. It also supports passing in query parameters, headers, and other options.

• cy.get() – This command is used to retrieve an element from the DOM. It can be used to access elements by ID, class name, or CSS selector.

• cy.type() – This command simulates typing into an input field. It can be used to type text, numbers, special characters, and more.

• cy.click() – This command simulates clicking on an element. It can be used to click buttons, links, checkboxes, radio buttons, and more.

• cy.wait() – This command pauses execution for a specified amount of time. It can be used to wait for an AJAX request to complete, or for an animation to finish before continuing with the test.

15. Can you show me some code that uses custom commands in Cypress?

Yes, absolutely. Here is an example of code that uses custom commands in Cypress:

const cypressCustomCommands = {
login: (username, password) => {
cy.get(‘#username’).type(username);
cy.get(‘#password’).type(password);
cy.get(‘#submit-button’).click();
},
logout: () => {
cy.get(‘#logout-button’).click();
}
};

Cypress.Commands.add(‘login’, cypressCustomCommands.login);
Cypress.Commands.add(‘logout’, cypressCustomCommands.logout);

This code creates two custom commands for logging in and out of a website. The first command takes two parameters – username and password – which are used to fill the appropriate fields on the page. The second command simply clicks the logout button. Both commands can then be called from any test script using the syntax `cy.login()` or `cy.logout()`.

16. What is the purpose of cy.wait()?

The purpose of cy.wait() is to pause the execution of a test until a certain condition is met. This allows for tests to be more reliable and accurate, as it ensures that all necessary conditions are in place before continuing with the test. It also helps prevent race conditions from occurring, which can lead to unexpected results or errors. By using cy.wait(), developers can ensure that their tests will run smoothly and accurately every time.

17. How can you verify whether data has been written to local storage or not?

Cypress provides a number of methods to verify whether data has been written to local storage or not. The first method is to use the cy.getLocalStorage() command, which will return an object containing all the key-value pairs stored in local storage. This can then be used to check if the expected values have been written correctly.

The second method is to use the cy.setLocalStorage() command, which allows you to set specific key-value pairs in local storage and then verify that they are present using the cy.getLocalStorage() command. This ensures that only the expected values are present in local storage.

Finally, Cypress also provides the cy.clearLocalStorage() command, which clears all existing key-value pairs from local storage. This can be used to reset the state of local storage before running tests, ensuring that any unexpected values are removed.

18. What is the purpose of cy.clearCookies()?

The purpose of cy.clearCookies() is to delete all cookies associated with the current domain. This command allows Cypress users to clear out any existing cookies that may be stored in the browser, allowing them to start fresh and ensure that their tests are running on a clean slate. By clearing out any existing cookies, it also helps to prevent any potential conflicts between different test runs. Additionally, this command can help to improve the performance of tests by reducing the amount of data that needs to be processed.

19. What’s the difference between cy.get() and cy.find()? Which one should be used in certain situations?

The main difference between cy.get() and cy.find() is that cy.get() is used to access a single element, while cy.find() is used to access multiple elements.

cy.get() should be used when you are looking for an exact match of the selector you provide. It will return the first matching element it finds in the DOM. This method is useful if you know exactly which element you want to target.

cy.find() should be used when you are looking for multiple elements that match your selector. It will return all matching elements it finds in the DOM. This method is useful if you need to interact with multiple elements at once or if you don’t know how many elements there are on the page.

20. What are some common mistakes made while writing test cases in Cypress?

One of the most common mistakes made while writing test cases in Cypress is not properly organizing tests. It’s important to structure your tests so that they are easy to read and understand, as well as maintain over time. Additionally, it’s important to ensure that each test case has a clear purpose and goal. Without this clarity, it can be difficult to determine if the test was successful or not.

Another mistake often seen when writing test cases in Cypress is not taking advantage of all the features available. Cypress offers many powerful tools for creating robust tests, such as assertions, commands, and custom commands. Not utilizing these features can lead to inefficient and unreliable tests.

Finally, another mistake commonly seen with Cypress is not using the best practices for debugging. Debugging is an essential part of any testing process, and Cypress provides several helpful tools for debugging. Taking the time to learn how to use these tools can save time and effort in the long run.