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

Exercise 01 (Solution)

[00:00] First, let's create the test user credentials by declaring this variable called user info and calling generate user info to get the value. This function generate user info is another helper and it will generate random username, the full name, and an email for our user. So once we have this, all we need to do is also create a password. So let's create a password and assign it a value of Super secret to be, well, Super secret in our tests. So these are the user credentials, but the user record in the database does not exist just yet.

[00:30] To make it exist we're gonna use our Prisma client. Since our application uses Prisma, we will do prisma. User. Create and provide this data object with our generated user info and a password. In this case, we're gonna hash the password because that's one of the best practices how you store passwords in a database.

[00:48] So once we do this step, now this user variable, this user object is actually a pointer to the user record in the database. And all that's left for us to do is to return this user object and also the password because the password will not be returned on the user record. Now if we leave this utility function as is and use it in tests, it's gonna create this user in the database and that would be it. But following the best practices of testing, we also need to clean up after ourselves. Something somewhere along the lines has to remove that user from the database so we don't pollute it every time we run the test.

[01:20] Normally, you would achieve this by deleting the test resources or maybe dropping the entire database in test hooks, like after each or after all. But we can do something better today. Let's go to this object here, this one that we return, and make it a disposable object. Disposable objects are part of standard JavaScript API, and what they allow you to do is collocate the logic that you have, for example creating a user, and the cleanup side effect, basically the dispose callback, in our case deleting that user. To make the object disposable, we will declare a special key here with the value symbol as sync dispose.

[01:54] This will let JavaScript know that this object has to run this logic here when it's being disposed, in other words, garbage collected. In the context of our test, this callback will be called when the test is done running. So what we gonna do here is delete the user from the database. I will use this call from here which will call await Prisma user deleteMany and provide the proper query targeting the user by ID, user. Id, which points to our test user that we just created.

[02:25] Of course, I'll make this callback as async so we're able to use the await syntax. So by doing this, we're able to co locate our utility logic and the cleanup for that logic which I think is pretty neat. We don't have to spread it across our test setup anymore. Now that we have this create user utility, let's put it to use in our tests. I'll head to this authentication basic.

[02:45] Test. Ts and complete this first scenario. It says authenticate using an email and password. So we're talking about a successful authentication flow. So let's start by creating a test user.

[02:55] Over here, I will create a variable called user and assign it the result of calling out createuser utility. Notice that here I'm not using const, olet, or war, I'm using the special keyword that's called using. With this special keyword, I'm letting JavaScript know that the user object here is a disposable object. This way JavaScript will know to dispose of this object in a special way, in our case by deleting the test user from the database. Now that we have the test user, let's navigate to the login page using our navigate fixture and providing it the path slash login.

[03:27] So once we're on this page, what we want the test to do is to interact with it the same way the user would. And that means filling in the login form. So to do that, we will use the page fixture to find the input elements. There are multiple ways to find input elements. You can find them by role, the text box role, but what I prefer doing is finding them by the label text.

[03:47] This means that we're also making an implicit assertion that our input has an associated label in the UI and this helps the user to understand what is this input stands for. So here we're gonna use await page get by label and enter the label. In that case, it's gonna be username And once we done this, Playwright will return us a locator as you already know. This locator allows us to do multiple things. In this case, we'll do dot fill and fill in the value to that input.

[04:14] So here we need to put the username. It's not gonna be any fixed value. Instead, we can refer to a user that user created and get its name property. You can notice I'm using this exclamation point here to let TypeScript know that this user and its name will be defined. This is to make sure that we comply with the types because when we retrieve a user from the database, we don't know if they would exist.

[04:36] But in the test case, we know that for sure. So once we've done this, we need to also enter the password. We'll do it in a similar fashion. We will call page get by label, in this case password and enter our password so it's also stored in our user object. And now all that's left is to click the login button.

[04:54] So let's locate that button on the page by its role, button, and its accessible name that says log in. And now call dot click which will click on that button. So our login form is now filled in with the test user credentials. The assertion here would be to make sure that the user, or in our case, the test, sees certain UI elements that correspond to the authenticated state. In other words, elements that mean that you have successfully logged in.

[05:26] So what we're gonna do here is to find a link element on the page with the username. So I will do page, again by role, link, and accessible name, it'll be the same as user dot name. And the assertion here would be to be visible. Now let's run this test. In the terminal, I will run npm run test end to end.

[05:48] I can see this test failing which is great. That means that I made a mistake. If I follow this test error, Playwright says that it cannot find this element link with the accessible name username. So one of the reasons this might happen is the authentication didn't succeed. If I take a look at my test, here's the error.

[06:06] I'm actually providing username which is full name instead of user dot username. So once I do this correction and run the tests again, now it will pass. And following this example, let's complete the second test case for a failed authentication flow. So here, go to the second test closure. We'll do absolutely similar steps.

[06:26] We'll go to the login page so await navigate slash login. We will try filling in the form. Let me just copy this over here. So let's fill the form. Here, we won't have any test user because we want the authentication to fail.

[06:41] So I can provide anything here. Cody and my password. Then once I click on this button and submit this form, I want to make sure that our app communicates to the user that authentication has failed. One of the ways that communication can happen is through some error messages on the screen. So I head to the assertion here and write that I expect an element by role alert to have another element inside which I will target by text, by text, and this will be the error message.

[07:12] So in our case, it should be invalid username or password. And the matcher I'm using is to be visible, to make sure that this error is visible on the screen. And now let's run the tests again to confirm that they are passing. So npm run test end to end. And both of our authentication scenarios pass.

[07:31] One thing I would like to point out is our test user over here. You might have heard a rule that you shouldn't rely on test users, and that's a great rule, but it speaks about how you act in your tests. In other words, you shouldn't perform actions and have expectations that the real user wouldn't do or have, like finding elements by their internal attributes or making sure that some functions were called. Your users don't know about any of that. But in our case, when I say the test user, I'm referring literally to this user object that we use for testing purposes.

[08:02] For all our systems care, this is an actual user that exists in the actual database. And what's important here is that how we act in the tests, how we interact with our app. In our case, we're following the actual user journey step by step, performing actions that our users would perform, and this is what makes a great end to end test.

Basic

[00:00] Let's start from taking a look at what authentication methods we have in our app. If I go to the login page, I can see that the user can log in with their username and password. This is one of the most common ways to authenticate on the web. But they can also log in using their pass key and even external accounts like GitHub if they have any. Your task in this exercise is to test the username and password authentication option.

[00:21] And to do that reliably, you have to understand how it works. So when the user submits their credentials, the client sends them to the server to validate. In other words, to make sure that the user by this username indeed exists in the database and they have provided the right password. What's important here for our tests is to understand that the user has to exist in the database for this authentication to succeed. And this is where you come in.

[00:43] You will implement the create user utility that's gonna generate a test user and put it in the database. And once you're done with that, you will start with a test case focusing on the successful authentication flow. You will use that utility function to create a test user, and with those credentials, you will follow the UI and interact with it the same way the user would to eventually log in. And at the end, you will assert the successful authentication the same way the user would through the UI elements visible on the page. After that, you will have another test case focused on the failed authentication attempt, for example when the user provides wrong credentials.

[01:15] And at the end, don't forget to run your tests to make sure that they are passing.

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.

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

Exercise 04 (Solution)

Protected logic

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

Transcript

Basic

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