Master testing user behaviors behind authentication by managing notes in your app. Enhance your skills with practical, hands-on exercises.

Exercise 04 (Solution)

[00:00] You will be interacting with authentication in two primary ways in your end to end tests. The first one is testing authentication as a feature, and in that case, you need to make sure that performing certain actions like a and b over here eventually results in the authenticated state, the user being successfully authenticated. This is the goal and intention of this test. But when authentication becomes a part of a different feature, for example, requiring the user to be logged in in order to access a certain page or perform a certain action, the story will be a little different. In that case, authentication becomes a prerequisite in order for us to even get to the things that we wanna test.

[00:36] In this case, let's say we wanna make sure that performing action c results in the application getting to the state d. This is what we want to test. This is our system under test. But it won't work without the authentication. The problem here, if we try to follow a regular authentication flow as a part of this test, we might introduce unexpected issues.

[00:55] For example, if the step b here fails, well, naturally authentication will also fail and our entire feature test will also be marked as failed. But does that really mean that performing c doesn't result in the d? Not really. Instead, it only means one thing that we made a mistake. We introduced extra context to this test in the form of the whole authentication flow, and now it affects the test results for the feature that's not really related to the step B over here or step A.

[01:22] It's the golden rule of assertion all over again. The test must only fail when the intention behind it is not met. So in order for this test to be functioning correctly, this entire authenticated state has to be treated as a prerequisite, as a part of the test setup, a given. Basically, we're always starting in the correct and valid authenticated state and then continuing with what we want to do to test a particular feature. And there are multiple ways how you can do that in Playwright.

[01:48] If you take a look at the authentication recipe in the Playwright documentation, it recommends creating a special test case for authentication that will follow the steps to authenticate, make sure that the end result is indeed a successful authentication session, and then it will store that session by using this storage state method that will write all the cookies and local storage entries and whatnot in the given file. That is so you can later hydrate from that stored file in other tests. You do that in your Playwright config by defining your tests, saying that they depend on this setup project, this is the one that runs this authentication flow and writes the state to disk, and use the option storage state providing you the path to this stored authentication state. And while this might sound fine on paper, I believe there are multiple issues with this approach. Well, the biggest issue here is that we are literally introducing shared state.

[02:40] We are saying that all these tests depend on these tests. In other words, if the setup project here fails, all the dependent tests will also be marked as failed, even though there might not be necessary anything wrong with them. And another issue here is that the storage state API, while powerful, is rather low level. It provides you no means of actually validating that the stored authentication sessions are still valid. What if you refactored your logic to, let's say, add or remove certain fields from the Joke token that you store for your user?

[03:08] Well, now you have risk of running your test against the obsolete authenticated state, giving you irrelevant results. Luckily, there is another way to manage authentication in Playwright, and that is by using personas. First, I will install a package called playwright persona as a dependency in my project. So in the terminal, npm install playwrights dash persona as a dev dependency. Alright.

[03:31] If you think about it, there may be multiple types of users that can be logged in and interacting with your app. It may be a regular user, a user with 10 posts, an editor, an admin, maybe even a user who's been banned for suspicious activity. All of those are different personas that you can assume in your tests. And using the Playwright Persona package, as the name suggests, will help you model those different authentication scenarios as a part of your test setup. Because personas are going to use the browser to actually log in, I'm gonna implement them as a Playwright fixture.

[04:03] So I will head to the file test extend. Ts where I have all my fixtures and declare my first persona. To do that, I will import from the playwright persona package a function called define persona. And then I will declare a variable called user and assign it the result of calling define persona. This function accepts two arguments.

[04:25] The first one is the persona name. This is just a string for me to know what kind of persona I am using. You will see how will come into play in the tests a little later. And the second argument is the options object that will describe the life cycle of this persona. There are a few methods that belong to the persona's life cycle and the most important one is the create session method.

[04:47] The library will call this method whenever it needs to create a new session belonging to this persona. And in this method, I'm going to describe how to actually achieve this persona through all the setup parts and the UI automation. I will start by creating a test user in a similar way how we did during testing authentication. So here, I will declare a variable called user and assign it the result of creating the user record in my database. Now having this test user, I need to go into my application and actually go through the login flow to be logged in as that user.

[05:19] To do that, I need to automate the browser. Luckily, the create session method exposes the first object, which is the context, that has the page object. This is the same page fixture you use in your playwright tests. And with the page here, I can automate whatever I need to. For example, to go to the login page, and then enter the username and the password using my test user and then submit the form by clicking on the login button.

[05:43] Here, I wanna wait until the user is logged in by waiting a specific element, just the username in the text, to become visible. Notice that this is not an assertion because technically this is not a test either. This is a part of the test setup. And the last thing that I want to do is to return the session object from this create session method. To do that, I will just return an object that contains the user record which points to the record created in the database.

[06:07] The thing is different methods of this persona lifecycle will have access to my session object and you will see how I'm gonna use them. So the next method I have to define is called verify session. In this verify session method I need to describe the logic that can verify any stored authenticated state to be valid or invalid. And to do that, I can access both the page fixture and the session object in the arguments. The session here is the same object I returned from the create session method.

[06:38] And now, again using playwright automation, I can check if the session is valid by locating certain elements on the page. So I'll go to the home page by page go to slash and make sure that the session dot user dot name is visible in the DOM. And notice that I am providing an option here to the to be visible matcher that has timeout set to one hundred milliseconds. That is done so my verification is blazing fast. In other words, I don't want Playwright to wait until this element appears.

[07:07] If the stored session is invalid, that UI element will never appear, so I want to fail as fast as possible. Both create session and verify session are required methods on the persona. But there's also another method that I can use that is called destroy session. As you might have guessed from the name, this method will be called when the session is destroyed, and I can use it to clean up any temporary resources I introduced for the session, for example like my tested user. So here I can get access to the session object and use the Prisma client to delete the users by the id of my tested user.

[07:42] I'm getting it from session dot user. Id. Once again, this is the same object returned from the createSession method over here. So createSession returns a user and I can use that session in both verify session and destroy session methods. Now that I have these different persona methods implemented, let's talk about when and why they will be called.

[08:02] So when I'm running my first test that uses this persona, the library will call the create session method to create the session. It will follow my steps, preparing the resources, and clicking through the UI, and eventually arriving at the session object. Once this is complete, the library will store this authenticated state, meaning cookies and local storage, on the disk. That is done so the subsequent test runs don't have to authenticate again as long as the session is valid. And how does the library know if it's valid?

[08:30] Yes, through the verify session method. So in a subsequent run, it will detect that there is a stored authenticated state and instead of creating session, it will call verify session first, giving you the stored session object. And here I am able to let the library know is this session still valid. If it is, it will continue with the test as usual using that stored authenticated state. But if it's not, something different will happen.

[08:54] First, the library will call destroy session to dispose of the outdated invalid session. And this session object here actually points to the outdated authenticated state. So I can clean up the resources before new test resources are created. And once the session is destroyed, the library performs the entire authentication process again by calling the create session method. On its own, this user persona that I created over here is not a playwright fixture so let's make it into one.

[09:21] I will go to the fixture interface here that describes the type definitions for my fixtures and introduce a new fixture called authenticate. To annotate it, I will once again go to the playwright persona package and import the type called authenticate function. I will use this type here and as the type argument I will provide an array of my personas. Type of user. So by doing this I will infer all the session types and and also the persona name on the authenticate fixture.

[09:49] Now to implement the actual fixture, I will use another helper called combine personas. Now this function will combine this personas declarations, as many as you have, into an actual playwright fixture. So I will get to this fixture objects over here, the implementation, and implement authenticate by combining personas, giving it the only persona I have, which is the user persona. Now that I have my authenticate fixture ready, I can use it in my tests to authenticate. I will go to the test at end to end slash notes create.

[10:20] Test. Ts and use that new authenticate fixture. I will call this fixture and await its result because it returns a promise. You might notice that it expects an argument. Here, I need to provide an object with a single key as which is the name of the persona I want to use to authenticate us.

[10:38] And immediately you see the type safe authentication from the get go. The personas are all strictly typed as well as their session object. So let's get that one. As a result of calling the authenticate function, we're getting the session object with the user because this is this is the property I defined on the object that I returned from the create session method of my persona. Once I call this authenticate fixture with the persona that I want, my test will immediately assume that persona from this moment on.

[11:06] So now I want to get to the functionality that is behind authentication. In this case, I want to make sure that logged in users can create notes. So I will grab the navigate function for type safe routing and call navigate users username nodes slash new. This route requires a dynamic segment here, dynamic path segment which is the username. So I'll provide it as the second argument by providing username, and I will grab the username from the user dot username.

[11:38] Next, I want to create a note, and I will do it in the UI the same way the user would. I will locate an input by the label title and fill in the title of my note, in this case, my new note. Also, another input by the label content, well, I will provide hello world as that note's content and finally, I will click on the button that says submit. And hopefully, this creates a new note. But I don't wanna hope here, I wanna know for sure.

[12:02] This is why I am writing this test to begin with. And I can assert that the note has been successfully created by writing two assertions. The first one, that the heading element on the page with my notes title will be visible, and the second one is that the content of my note will also be visible inside the respective element. Notice how I'm chaining this locators over here the same way you can chain locators in v test when testing your components. And now let's run this test by running npm run test end to end in the terminal and see this scenario as successfully passing.

[12:37] Now let's recap everything that's happening in this test. So first things first, we're using the authenticate fixture to log in as the user persona. And this gives us the logged in authenticated state to actually get to this node creation functionality that is behind authentication. Very handy, we're grabbing the session object with our test user that's currently logged in, going to the route that's normally protected and requires the user session, provide this dynamic segment so we go into the proper notes of the proper user, and past that point just automating our actions in the UI by filling in the form to create the note, submitting it, and making sure that the note is created by being visible on the screen. As it often happens with end to end tests, all the heavy lifting here is done in the Authenticate fixture, so let's take a closer look at it.

[13:26] We know that the Authenticate fixture is the result of calling combined personas, this is the function from the PlaywrightPersona library, And it accepts all the personas that we want to use in our tests. The persona itself is just an object that consists of the name, in this case user, and different lifecycle methods, where we describe how to get to the authenticated state specific to this user, also how to verify that state once we are restoring it from the file system, and how to clean up, how to destroy this session in case we creating some resources associated with it. There are multiple authentication strategies that you might be using in your end to end tests. You might have a designated test user by using fixed credentials like email and password. You may create a one time test user as I am doing over here.

[14:13] Every time I have a new authentication, it will result in the random user. So this is what I call reproducible randomness. Or you may create a completely random resources. And luckily, the Playwright persona library accommodates all of those use cases through the create session, verify session, and also destroy session lifecycle methods. I have mentioned multiple times that successful sessions are stored on disk.

[14:36] But where exactly is that? If you go to your project, you will find a playwright directory that has a dot auth directory. And this is where all these test sessions are stored in JSON files like this one. Because sessions contain sensitive information by design, make sure to ignore this entire dot auth directory in git, but you can still keep it persisted between your CI jobs for faster authentication.

Protected logic

[00:00] Prior to this point, you've been testing different authentication methods. In other words, different features you have in your app. But now it's time for you to focus on behaviors that live behind authentication. For example, in the epic notes, logged in users can create and manage their notes, and that's a perfect candidate for you to test in this exercise. But keep in mind that in this case, authentication is no longer an action you perform in your test, but instead a part of the given, a part of your app's initial state.

[00:28] So follow the instructions and pay attention at the difference when it comes to testing authentication as a feature and as a prerequisite for other features.

Do you know this feeling when you finally trust your tests? When running them no longer makes you brace for impact, but instead gives you the confidence to ship without second-guessing every deploy. End-to-end tests rarely earn that trust. They've earned a reputation for being expensive, slow, and unreliable, and most of the time, that reputation is deserved.

Today, I want to change that for you with Playwright.

In this workshop, my goal is to make you rethink what end-to-end testing can be. That means stepping beyond the cargo-culted patterns that gave E2E tests their bad reputation in the first place. That means getting so good at Playwright that you would feel confident writing tests that are meaningful and performant, and, dare I say, a pleasure to maintain.

Welcome to the Playwright workshop!

## What You'll Learn

End-to-end tests can get really complex really fast. I will teach you how to deal with that complexity by making intentional choices throughout the workshop: from configuring Playwright to arranging your test setup to reduce flakiness and get the test suite that you can trust.

On top of that, you will be crafting your own test experience through custom fixtures, disposable test data, and reproducible authentication snapshots. This will help you orchestrate tests for complex, real-world applications.

### Fundamentals

In the first block, you will get comfortable with Playwright. From installing it and covering the essential configuration options for a great testing experience both locally and on CI, to getting familiar with the test structure, the `page` object, and why it gives you element *locators* instead of direct DOM references. You will wrap up by writing your own custom fixture for type-safe page navigation in your end-to-end tests.

### Authentication

You will learn the difference between testing authentication as a feature and testing features that are *behind* authentication. Yes, those require entirely different approaches. Then, you will write tests for the most common authentication methods in web applications. With **basic auth**, you will create a disposable `createUser()` utility that creates a test user in the database and deletes it when the test is done. With **two-factor authentication**, you will create test OTP tokens and store their verification records in the database for your test user. And with **passkeys**, you will leverage a Chrome Developer Protocol session to create a web authentication client with the passkey you provide and use it in your test.

After that, you will explore how to create and manage authentication in your test setup using [Personas](https://github.com/kettanaito/playwright-persona), reproducible snapshots of different authentication states that bridge the DX gap of `setStorageState` in Playwright.

### Guides

Next, you will dive straight into practical tips for writing end-to-end tests: from provisioning mock databases and test data to mocking client-side requests. As a bonus, I will show you how to write tests by recording your interactions in the browser using Playwright's extension for Visual Studio Code.

### Debugging

And yes, I've saved the best for last. Debugging.

It's become somewhat of a tradition to include debugging techniques in my workshops, and this one will be no different. You will master the UI mode to preview and debug your tests *visually*, and after that, learn how to debug failed CI tests with the Trace Viewer. **This is, seriously, such a time-saver.** No more guessing why a test failed three commits ago on a machine you don't have access to. You will have the entire test run at your fingertips.

## Who Is This Workshop For

This workshop is for any developer who wants to write end-to-end tests they can actually rely on. For everyone who has watched a CI pipeline turn red because of a flaky test that passes locally. For everyone who has been told that end-to-end tests are inherently slow and unreliable, and refused to accept that as the answer.

You don't need prior Playwright experience to get the most out of these exercises, but a working familiarity with modern web applications and a healthy skepticism toward the current state of E2E testing will serve you well.

Master Playwright end-to-end testing: setup, authentication (basic, 2FA, passkeys), mocking, fixtures, and debugging with UI mode and Trace Viewer.

React End-to-End Testing with Playwright

Artem Zakharchenko

Writing tests for their own sake is a pointless chore:

```tsx
describe('add numbers', () => {
  it('should add two numbers', () => {
    expect(add(1, 2)).toBe(3)
  })

  it('should add two other numbers', () => {
    expect(add(3, 4)).toBe(7)
  })
});
```

Another annoying testing problem is when tests are too brittle, and paint your logs red even though the application seems to work just fine.

When your tests lack real purpose or seem to fail for no good reason, it's no wonder you start to question their value.

Tests are supposed to give you confidence in your code, and save you from shipping broken stuff to prod. So why does writing them feel like such a burden?

The problem is that tests like these are focused on implementation details instead of the underlying behavior. Everyone talks about the importance of testing, but there's a lack of understanding about how to write tests that are actually useful.

How would it feel to have 100% trust in your tests, knowing that any failures are not a false alarm? What if you could seamlessly translate the underlying behavior of your application into tests that are easy (and even fun) to write?

It's possible, but it requires you to take a step back from just syntax.

In order to have the confidence you're testing the right things in the right ways, you need to dig into the underlying patterns behind the scenes of a testing framework.

This is exactly what you will do in Testing Fundamentals.

In this workshop, Artem Zakharchenko, testing expert and creator of the Mock Service Worker API mocking library, will guide you through creating your own version of the Vitest testing framework.

Building a testing framework from scratch will give you a deep understanding of how the pieces fit together, and change the way you think about testing for the better.

## What You'll Learn

The workshop is broken out into four parts, each with its own challenges and exercises that build upon the last:

### Principles

First, you'll explore the principles and mental models that underlie testing strategies. This is where you will begin to distinguish between the intention of your code and its implementation details. When you focus the intention of what your code should accomplish, you can write tests that are more resilient to change.

### Test Structure

Next, you'll do a deep dive into the structure of the testing framework. You'll create your own `expect` and `test` functions, configure your test environment, and use hooks to manage side effects in your tests.

### Testing Asynchronous Code

Testing asynchronous code requires a slightly different approach when compared to testing synchronous code. Here you'll practice with testing promises and async functions, as well as handling errors and rejections.

### Moving to Vitest

Once you've learned the fundamentals of testing and built your own mini-framework, you will migrate your tests to the Vitest framework. This process will cement your understanding of not just the "hows", but also the "whys" of testing.

## Who This Workshop Is For

This workshop is for developers who have some testing experience, but feel like they're missing the bigger picture. If you're tired of writing tests that feel like a chore, and want to understand how to write tests that are actually useful, this workshop is for you.

Testing Fundamentals

Let’s face it, mocking can be really confusing.

First, you need to know what to mock. Then, find the right way to mock that thing so it doesn’t compromise your test suite. Over-mock, and your tests become pointless. Under-mock, and they get brittle instead.

In either case, you put in so much effort, and you don’t feel like you’re getting much in return.

This is where Artem comes in. He’s been proving developer misconceptions around mocking wrong for nearly a decade, and he’s here to make you a mocking pro.

## What You’ll Learn

In this hands-on workshop, you’ll learn:

- The purpose of mocking;
- What to mock and when;
- How to write mocks that bring value instead of being a maintenance chore;
- How to separate your mocks from implementation details;
- Type safety strategies for your mocks;
- And **all the mocking techniques** you will need to test your code!

By solving targeted, real-world problems using the Vitest framework, you’ll gain a comprehensive understanding of mocking and finally unlock it as a useful tool in your testing arsenal.

## Workshop Structure

This workshop contains 6 exercise blocks dedicated to various techniques on mocking different data types.

### Boundaries

Understand what mocking really is, and learn how it helps you create test boundaries. See what each mock you introduce does to your tested code using visual metaphors.

### Mocking Functions

Functions are at the heart of JavaScript logic. Learn how to mock functions for effective input-output testing. Create mock functions, spy on function calls, and mock function implementation to tap into the right behaviors of the tested code.

### Mocking Date and Time

Eliminate the side effects of ever-changing date and time in your tests. Learn how to freeze time and mock date/time-dependent code to ensure consistent test results across different runs and time zones.

### Mocking Globals

Explore how to mock implicit dependencies, in a non-intrusive way. Learn to mock global values, methods, and environment variables to create the perfect test setup without meddling with things you don't own.

### Mocking Network

Gain control over network communication and test your client-side code reliably. Intercept requests and mock responses using Mock Service Worker. Reproduce various network scenarios, from success and error responses to offline behavior and response timing.

### Mocking Modules

Understand when to use module mocking and explore alternative techniques before you do. Learn how to mock modules in a type-safe and efficient way using built-in APIs in Vitest.

## Who This Workshop Is For

This workshop is meant for all developers, both those who are new to automated testing and those who’ve been writing tests for years. If you are unsure when to introduce mocks into your test suite, or how to do that so you don’t have to refactor it the next day, this workshop was made specifically for you.

Mocking Techniques in Vitest

The closer your tests resemble how your software is being used, the more confidence they will give you. There’s so many great patterns stemming from this simple rule, patterns I’m sure you’re already using to write better tests.

Then, there’s the elephant in the room. **Your test environment.**

For decades, web developers have been testing their UIs in make-believe environments that are neither the browser nor Node.js. It made them come up with a frankly ridiculous amount of test setup, polyfills, and workarounds just to make it work. Remember when you had to mock `location` in tests? `window.matchMedia`? Yeah…

It’s time to abandon such practices. The tools have improved and there’s no excuse for you to be sleeping on it. It’s time for you to learn how to use Vitest Browser Mode for in-browser component testing!

## What You’ll Learn

In this workshop, you will learn a new approach to component testing that’s both different and the same. It is different because you will write and run your tests in the actual browser, taking advantage of the standard APIs and powerful browser automation. It is the same because it’s still the component level test you know and love, with rendering, querying, and asserting. 

Your users don’t interact with the UIs you build in JSDOM. They do that in the real browser, and now your tests will too!

### **Sunsetting JSDOM**

The first step in our journey is understanding why browser-like environments fall short. JSDOM has served us well, but it's time to recognize its limitations. You'll experience firsthand how browser-like environments like JSDOM are letting you down.

We'll explore examples of valid JavaScript code that works perfectly in browsers and Node.js but fails in JSDOM, undermining the value of the tests you work so hard to write. You'll discover why these inconsistencies happen and why moving to real browser testing is the solution.

### **Vitest Browser Mode**

Vitest Browser Mode allows you to run isolated component-level tests in the actual browser while providing the convenience and flexibility of integration-level testing. It's not a full end-to-end testing framework like Playwright or Cypress, but rather the perfect middle ground for component testing.

In this module, you'll learn:

- How to install and configure Vitest Browser Mode in your project;
- The technical differences between how JSDOM and Browser Mode run your tests;
- Steps needed to migrate existing JSDOM tests to Browser Mode;
- How to set up Playwright as the browser automation provider for your component tests;
- Common setup scenarios like applying global assets in tests and configuring Vitest for both unit and component-level testing within the same project.

### **Best Practices**

Choosing the right tools is important, but knowledge that transcends any particular tool is even more valuable. In this section, we'll focus on five key areas of best practices when it comes to testing your React components:

- **Queries**: Find elements on the page the same way your users or their assistive technology would;
- **User events**: Interact with the tested elements from the user’s perspective;
- **API mocking**: Use Mock Service Worker to intercept requests and handle their responses as well as discover how to efficiently use MSW in Vitest Browser Mode by creating a custom test context;
- **Element presence**: Test elements that should (or shouldn't) appear on the page reliably without false positives or flaky results.
- **Page navigation**: Learn where to draw the line when testing page transitions and routing in the actual browser.

### **Debugging Tests**

The true value of tests comes when they fail. But dealing with failing tests can be quite frustrating without the right techniques.

In this block, you'll learn some of my favorite debugging techniques that go well beyond console logging:

- How to inspect the DOM state at any point in test;
- Using the debugger statement to stop JavaScript execution entirely;
- Wielding conditional breakpoints to step through the problematic code.

These techniques will transform your approach to test failures from dread to confidence so the next time you see a failing test you will know what to do.

## Who Is This Workshop For

This workshop is for all React developers who want to write reliable and valuable tests for their components. Whether you're new to component testing or have been writing tests for years, you will inevitably learn new tools, APIs, and techniques to gain more value out of your test suite. That’s my sole motivation behind this material.

React Component Testing with Vitest

Do you know this feeling when a tool “clicks”? When you suddenly become so comfortable with it that it’s no longer just a means to an end but an instrument to craft better experiences for yourself. Over the past decade, that transition has happened with a bunch of tools for me.

Today, I want it to happen for you with Vitest.

In this workshop, my goal is to make you a Vitest superuser. And that means stepping beyond the basics and into the advanced. That means getting so good at Vitest that you would feel confident crafting custom test experiences, understanding the inner works of your test runner, and equipping that knowledge to solve everything from complexity issues to poor test performance.

Welcome to the Advanced Vitest Patterns workshop!

## What You’ll Learn

The overarching theme of this workshop is ***customization***. I believe your experience with tools is defined by how well you understand them and how comfortable you are when it comes to customizing them. With this workshop, I’ve collected some of the best techniques and pieces of advice to make you a true Vitest superuser.

I’m also taking this workshop as an opportunity to teach you the importance of the test setup. Throughout the exercises, you will be crafting your own test experience through things like custom fixtures, matchers, and equality testers. This will help you orchestrate tests for complex, real-world applications.

### Setup

In the first block, you will get more comfortable with Vitest. From writing and debugging tests faster with the Vitest’s extension for Visual Studio Code, to configuring and visually exploring code coverage and setting up multiple test projects to use your test runner to the fullest.

### Context

You will learn how to customize your test experience by creating *custom fixtures*. Discover the fixture syntax, its life-cycle, and how to implement them in a type-safe way. Then, note down the best practices of fixture design to make sure your custom fixtures eradicate complexity, not introduce it.

### Assertions

Following the topic of customization, find out how you can supercharge your assertions. First, you will create your own matchers to help express your expectations toward your tested app and make your tests read like human language. Then, explore what is an equality tester and how you can teach the Vitest’s built-in `.toEqual` matcher to compare the incomparable.

Nail down how to write assertions for eventual states with `expect.poll` and become in full control of how much information you get out of failed assertions by understanding the balance between the hard and soft assertions.

### Performance

And yes, I’ve saved the best for last. Performance.

Learn how to profile slow test runs using built-in metrics in Vitest as well as the `vitest-profiler-plugin`. You will read the CPU and heap profiles, understand what they mean, and how you can use them to hunt down the problematic areas of your tests.

Everything past this point is techniques to make your tests faster. **We are talking up to x40 times faster** (that’s not a typo). Take a peek behind the scenes to see how Vitest orchestrates test runs and what defaults it has in place to ensure reliable results. Go through the difference between parallelization and concurrency in tests, explore the effects test isolation has on performance, and learn how to split your tests into shards for faster CI/CD jobs.

## Who Is This Workshop For

This workshop is for all developers who want to learn how to customize Vitest to create better, custom test experiences on top of it. For everyone who has felt like adding a new test in your project feels like fighting against the entire world. For everyone who has found themselves lost before a slow test suite.

As the name suggests, you will be going through advanced topics, which makes a prior basic experience with Vitest mandatory to get the most out of these exercises.

Advanced Vitest Patterns 

The Testing Bundle

Master Playwright for efficient end-to-end testing, covering setup, authentication, and debugging to enhance your web app's reliability.

React End-to-End Testing with Playwright Introduction

Workshop Introduction

Master end-to-end testing for web applications and ensure quality from UI to backend, using effective strategies to simulate real user scenarios.

Fundamentals Intro

Master end-to-end testing with Playwright by installing dependencies, configuring settings, and writing your first test to enhance your web development skills.

Exercise 01 (Solution)

Install & configure

Refactor your Playwright configuration to run the Epic Notes app in tests. Enhance your end-to-end testing skills and ensure your app functions flawlessly.

Exercise 02 (Solution)

Running the app

Enhance your Playwright tests with type-safe routing. Implement a custom fixture to avoid navigation errors and streamline your end-to-end testing process.

Exercise 03 (Solution)

Custom fixtures

Master Playwright by installing, configuring, and implementing custom fixtures, then prepare for essential authentication testing in your app.

Fundamentals Outro

Fundamentals

Master end-to-end testing by effectively handling authentication as both a feature and a dependency, ensuring robust app functionality and user experience.

Authentication Intro

Master username and password authentication by creating a test user and implementing successful and failed login test cases to ensure robust functionality.

Basic

Master two-factor authentication testing by implementing OTP code verification. Enhance security in your app while building effective test cases with ease.

Two-factor authentication

Master passwordless authentication by writing end-to-end tests for passkey login flows using Playwright and enhance your web development skills today.

Passkeys

Master efficient authentication testing and enhance your end-to-end tests. Unlock the secrets to robust application security with Item 99.

Authentication Outro

Authentication

Master end-to-end testing by enhancing your setup with best practices, efficient test data management, and user-centric approaches for reliable results.

Guides Introduction

Enhance your testing strategy by isolating your test database. Set up a dedicated test environment with Playwright for reliable end-to-end testing.

Mock database

Master note management by testing user authentication and data handling. Prepare and clean test data to ensure seamless functionality in your application.

Test data

Master end-to-end testing by using Playwright to automate changing a user's name in an app. Enhance your skills and streamline your testing workflow!

Recording tests

Master API mocking with Playwright to ensure reliable end-to-end tests by intercepting third-party requests and creating stable test environments.

API mocking

Master debugging techniques in end-to-end testing and enhance your development skills. Dive into practical exercises and elevate your problem-solving abilities!

Guides Outro

Guides

Master debugging end-to-end tests with Playwright. Gain insights into test failures and enhance your app's reliability through effective strategies.

Debugging Introduction

Debug and fix a failing test case in Playwright by using UI mode to visually trace actions and ensure user nodes appear correctly.

UI mode

Master debugging with Playwright's Trace Viewer to analyze a failed test run, identify issues, and enhance your testing efficiency. Fix it now!

Trace viewer

Master essential debugging in Playwright with UI mode, Trace Viewer, and more. Enhance your testing skills and troubleshoot like a pro!

Debugging Outro

Debugging

Master Playwright for comprehensive web app testing and enhance your skills with effective end-to-end user journey tests. Stay safe and test smart!

React End-to-End Testing with Playwright

React End-to-End Testing with Playwright

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Protected logic

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