Cypress vs Jest

Checking if a piece of software performs as expected is known as testing. This is frequently referred to as QA, or quality assurance, and tries to minimise the number of bugs that reach production.

Before sending code to production, we test software to find any mistakes, holes, or missing requirements and correct them.

Thorough testing increases the stability of our project, saves us time and money later on in bug-fixing, and increases the likelihood that our customers will be completely delighted with our product. A complete testing solution for the front end is offered by Cypress and Jest.

Cypress vs Jest - Table of Contents

• What is Cypress?
• What is Jest?
• Use
• Pros and Cons
• Comparison

What is Cypress?

With Cypress, an open-source test-runner, you can run your projects in a robotic browser much like a user would. With Cypress, we can specify what the browser should do like as open a URL, click a button, finish and submit a form, etc and verify that each action is matched with the appropriate result.

What's nice about this is how much what has been tested mirrors what the user would actually encounter. The user is the entire objective of software development, thus the more we can understand their perspective, the more likely we should be to find the most significant errors in our code.

"Time travel" is another amazing element of Cypress. We can see every test we've written on Cypress' automated browser, and we can just mouse over them to view a graphical representation of the outcome. Knowing what's breaking and when it's breaking is incredibly helpful.

Cypress is mostly used for end-to-end testing since it can quickly analyze entire features, despite the fact that it can also be used for unit and integration testing.  Cypress may be used to test anything that runs in a browser, making it simple to integrate with React, Angular, Vue, and other frameworks. Contrary to Jest and React-Testing-Library, Cypress does not include create-react-app by default. However, we can quickly install it using NPM or your preferred package manager.

If you want to enrich your career and become a professional in Cypress, then enroll in "Cypress Training". This course will help you to achieve excellence in this domain.

What is Jest?

A JavaScript test-runner is called Jest. A piece of software called a test-runner enables you to conduct tests to assess your app. It was initially made available as an open-source project in 2014 and is currently managed by Meta (previously Facebook).

Jest can be used in projects that employ other technologies such as Babel, TypeScript, Node.js, React, Angular, Vue.js, Svelte, and others. Jest may be installed using NPM just like any other library, and it needs very minimal initial configuration.

When creating React apps with create-react-app, Jest is already installed. Because it has many more built-in functionalities than merely running tests, which is not the case with all test runners, Jest is frequently referred to as a testing framework. 

Jest is frequently referred to as a testing framework because it has many additional functions in addition to test execution, which is not true of all test runners.

Should I use both Cypress and Jest together?

Jest and Cypress are often used in the same codebase. The distinction between integration and unit testing might become a little hazy with component libraries like Vue and React. The fact that we may apply the same tools (Jest & Cypress) to both situations further adds to the confusion. I advise you to test "user stories," or, to put it another way, confirm that users can consistently carry out important actions.

Cypress vs Jest - Pros and Cons

Pros and Cons of Cypress

Pros:

• The Cypress framework takes pictures while the test is running. In the Command Log, this enables QAs or developers to hover over a specific command to view exactly what transpired at that particular stage.
• Unlike Selenium, test scripts don't require explicit or implicit wait directives. Cypress automatically waits for requests and claims.
• Spies, Stubs, and Clocks can be used by developers or QAs to observe and manage the behaviour of server responses, functions, or timers.
• Before taking any action, the automated scrolling function makes sure that an element is visible (for example Clicking on a button)
• Only Chrome testing was previously supported by Cypress. Cypress now offers compatibility for the Firefox and Edge browsers thanks to recent revisions.
• Cypress runs instructions in real-time as the programmer types them, showing visual feedback as they do so.

Cons:

• Cypress cannot be used to run two browsers simultaneously.
• It doesn't support multiple tabs.
• Only JavaScript is supported by Cypress when generating test cases.
• Currently, Cypress doesn't offer compatibility for browsers like Safari and IE.
• Insufficient iFrames support.

[ Check out Top Cypress Alternatives ]

Pros and Cons of Jest

Pros:

• Provides a CLI tool so you can simply control your tests.
• Includes an interactive mode that instantly executes every test that is relevant for the code modifications you made in your most recent commit.
• .only and.skip syntax is provided to test a single test or skip tests. This function is beneficial when troubleshooting specific tests.
• Offers top-notch documentation, a wealth of examples, and a welcoming community
• Enables developers to easily simulate code while doing so is one of the most unpleasant tasks for testing engineers.
• Use the -coverage option or the collectCoverage property in the Jest configuration file to access code coverage provided by Jest through its CLI.

Cons:

• The primary drawbacks of Jest are due to its youth and lack of popularity among JavaScript developers.
• This kind of technology can be really helpful at times, such as when you can run and debug your tests in an IDE like WebStorm. WebStorm didn't even support running Jest tests till recently. This was just corrected in the most recent WebStorm release, although the debugger still cannot be used to step through your tests interactively.
• Compared to more developed libraries, it has fewer tooling and support for libraries available.
• Due to its inexperience, it could also be more challenging to use Jest universally for bigger projects that make use of many testing techniques.

Cypress vs Jest - Comparison

	Cypress	Jest
Programming Language	It uses JavaScript	It uses JavaScript
Category	Categories covered are  Integration Testing, End-to-End Testing, Unit Testing	It supports Unit Testing
Client-side	The main objective of Cypress is to test everything that runs in a browser and to verify how well an application flows from the perspective of the user from start to finish. It is designed to operate particularly well with contemporary JavaScript frameworks, but it also functions just as well with older server-rendered pages or programmes.	Methods, properties, UI element actions, and other front-end functionalities may all be tested with ease.
Server-side	Cypress can test back-end behaviors using the cy.task() command, which offers a way to run Node code, despite the fact that it is neither a framework for broad automation nor one for unit testing your back-end services. As a result, you can perform tasks required for your tests outside of Cypress's purview.	Much like front-end testing, back-end server behavior may also be tested with Jest.
Fixtures	For instance, the command "cy.fixture(filePath)" loads a fixed set of data from a file using Cypress's built-in fixtures capabilities.	Fixtures can be used, and Jest offers a number of helpful functions like beforeEach and afterEach. If you have tasks that you must perform repeatedly for numerous tests, use beforeAll and afterAll instead of setup, which should only be done once at the beginning of a file.
Group Fixtures	The 'cy.fixture' command in Cypress can be used to build group fixtures.	Jest enables fixtures for groups.
Mocks	With its built-in cy.stub() and cy.spy() functions, Cypress can stub and spy. It also automatically packages "lolex,", "sinon," and "sinon-chai," which all contribute to Cypress's mocking capabilities.	Jest makes it simple to fake any object outside the scope of your test by using a custom resolver for imports in your tests. With the powerful Mock Functions API and clear test syntax, you can spy on function calls by using mocked imports.
Grouping	Cypress allows you to arrange tests into configurations, but there is currently no method to execute the groups.	You are free to specify an unlimited number of test suites. Tests are grouped together using a describe block.

Conclusion

We'll use both Cypress and Jest to help with our testing. These tools, in our opinion, work best together and will enable us to achieve adequate code coverage. Since we have found Cypress to be quite user-friendly, we will use it for our end-to-end testing. We will use Jest for our unit tests because we have observed how well-used it is in many larger organizations.