Josh Justice
Josh Justice
Josh Justice has worked as a developer since 2004 across frontend, mobile, and backend platforms. As a consultant he collaborates with teams to help them deliver great apps by optimizing their tech stack and development practices. He also writes, speaks, and livestreams about React and React Native, testing, and software design.
React Advanced Conference 2023React Advanced Conference 2023
159 min
Effective Detox Testing
Workshop
So you’ve gotten Detox set up to test your React Native application. Good work! But you aren’t done yet: there are still a lot of questions you need to answer. How many tests do you write? When and where do you run them? How do you ensure there is test data available? What do you do about parts of your app that use mobile APIs that are difficult to automate? You could sink a lot of effort into these things—is the payoff worth it?
In this three-hour workshop we’ll address these questions by discussing how to integrate Detox into your development workflow. You’ll walk away with the skills and information you need to make Detox testing a natural and productive part of day-to-day development.
Table of contents:
- Deciding what to test with Detox vs React Native Testing Library vs manual testing- Setting up a fake API layer for testing- Getting Detox running on CI on GitHub Actions for free- Deciding how much of your app to test with Detox: a sliding scale- Fitting Detox into you local development workflow
Prerequisites
- Familiarity with building applications with React Native- Basic experience with Detox- Machine setup: a working React Native CLI development environment including either Xcode or Android Studio
React Summit 2023React Summit 2023
151 min
Designing Effective Tests With React Testing Library
Featured Workshop
React Testing Library is a great framework for React component tests because there are a lot of questions it answers for you, so you don’t need to worry about those questions. But that doesn’t mean testing is easy. There are still a lot of questions you have to figure out for yourself: How many component tests should you write vs end-to-end tests or lower-level unit tests? How can you test a certain line of code that is tricky to test? And what in the world are you supposed to do about that persistent act() warning?
In this three-hour workshop we’ll introduce React Testing Library along with a mental model for how to think about designing your component tests. This mental model will help you see how to test each bit of logic, whether or not to mock dependencies, and will help improve the design of your components. You’ll walk away with the tools, techniques, and principles you need to implement low-cost, high-value component tests.
Table of contents- The different kinds of React application tests, and where component tests fit in- A mental model for thinking about the inputs and outputs of the components you test- Options for selecting DOM elements to verify and interact with them- The value of mocks and why they shouldn’t be avoided- The challenges with asynchrony in RTL tests and how to handle them
Prerequisites- Familiarity with building applications with React- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Testing Library- Machine setup: Node LTS, Yarn
React Day Berlin 2022React Day Berlin 2022
131 min
Designing Effective Tests with React Testing Library
Workshop
React Testing Library is a great framework for React component tests because there are a lot of questions it answers for you, so you don’t need to worry about those questions. But that doesn’t mean testing is easy. There are still a lot of questions you have to figure out for yourself: How many component tests should you write vs end-to-end tests or lower-level unit tests? How can you test a certain line of code that is tricky to test? And what in the world are you supposed to do about that persistent act() warning?
In this three-hour workshop we’ll introduce React Testing Library along with a mental model for how to think about designing your component tests. This mental model will help you see how to test each bit of logic, whether or not to mock dependencies, and will help improve the design of your components. You’ll walk away with the tools, techniques, and principles you need to implement low-cost, high-value component tests.
Prerequisites:- Familiarity with building applications with React- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Testing Library- Machine setup: Node LTS, Yarn
React Day Berlin 2022React Day Berlin 2022
155 min
Building for Web & Mobile with Expo
Workshop
We know that React is for the web and React Native is for Android and iOS. But have you heard of react-native-web—for writing an app for Android, iOS, and the web in one codebase? Just like React Native abstracts away the details of iOS and Android, React Native Web extracts away the details of the browser as well. This opens up the possibility of even more code sharing across platforms.
In this workshop you’ll walk through setting up the skeleton for a React Native Web app that works great and looks awesome. You can use the resulting codebase as a foundation to build whatever app you like on top of it, using the React paradigms and many JavaScript libraries you’re used to. You might be surprised how many types of app don’t really require a separate mobile and web codebase!
What's included1. Setting up drawer and stack navigators with React Navigation, including responsiveness2. Configuring React Navigation with URLs3. Setting up React Native Paper including styling the React Navigation drawer and headers4. Setting up a custom color theme that supports dark mode5. Configuring favicons/app icons and metadata6. What to do when you can’t or don’t want to provide the same functionality on web and mobile
Prerequisites- Familiarity with building applications with either React or React Native. You do not need to know both.- Machine setup: Node LTS, Yarn, be able to successfully create and run a new Expo app following the instructions on https://docs.expo.dev/get-started/create-a-new-app/
React Advanced Conference 2022React Advanced Conference 2022
131 min
Introduction to React Native Testing Library
Workshop
Are you satisfied with your test suites? If you said no, you’re not alone—most developers aren’t. And testing in React Native is harder than on most platforms. How can you write JavaScript tests when the JS and native code are so intertwined? And what in the world are you supposed to do about that persistent act() warning? Faced with these challenges, some teams are never able to make any progress testing their React Native app, and others end up with tests that don’t seem to help and only take extra time to maintain.
But it doesn’t have to be this way. React Native Testing Library (RNTL) is a great library for component testing, and with the right mental model you can use it to implement tests that are low-cost and high-value. In this three-hour workshop you’ll learn the tools, techniques, and principles you need to implement tests that will help you ship your React Native app with confidence. You’ll walk away with a clear vision for the goal of your component tests and with techniques that will help you address any obstacle that gets in the way of that goal.you will know:- The different kinds React Native tests, and where component tests fit in- A mental model for thinking about the inputs and outputs of the components you test- Options for selecting text, image, and native code elements to verify and interact with them- The value of mocks and why they shouldn’t be avoided- The challenges with asynchrony in RNTL tests and how to handle them- Options for handling native functions and components in your JavaScript tests
Prerequisites:- Familiarity with building applications with React Native- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Native Testing Library- Machine setup: Node 16.x or 18.x, Yarn, be able to successfully create and run a new Expo app following the instructions on https://docs.expo.dev/get-started/create-a-new-app/
React Advanced Conference 2022React Advanced Conference 2022
161 min
Building for Web & Mobile with Expo
Workshop
We know that React is for the web and React Native is for Android and iOS. But have you heard of react-native-web—for writing an app for Android, iOS, and the web in one codebase? Just like React Native abstracts away the details of iOS and Android, React Native Web extracts away the details of the browser as well. This opens up the possibility of even more code sharing across platforms.In this workshop you’ll walk through setting up the skeleton for a React Native Web app that works great and looks awesome. You can use the resulting codebase as a foundation to build whatever app you like on top of it, using the React paradigms and many JavaScript libraries you’re used to. You might be surprised how many types of app don’t really require a separate mobile and web codebase!You will know:- Setting up drawer and stack navigators with React Navigation, including responsiveness- Configuring React Navigation with URLs- Setting up React Native Paper including styling the React Navigation drawer and headers- Setting up a custom color theme that supports dark mode- Configuring favicons/app icons and metadata- What to do when you can’t or don’t want to provide the same functionality on web and mobile
Prerequisites: - Familiarity with building applications with either React or React Native. You do not need to know both.- Machine setup: Node LTS, Yarn, be able to successfully create and run a new Expo app following the instructions on https://docs.expo.dev/get-started/create-a-new-app/