Posts - page 8

Recent posts

Add visual testing to your React app with Storybook

March 31, 2020  7 minute read  

In my last article, I started a React app from scratch, then integrated Parcel as the bundler, TypeScript for language support, SASS, ESLint for linting the code, and Stylelint for linting the style sheets. I didn’t include any testing capabilities, so that is next on my agenda. Let’s write a simple component to get started with testing. The component takes an “isBusy” flag. If it is true, then one icon is displayed. If false, a different icon is displayed. I’ll use text nodes in this v...

Building a React app with Parcel, Typescript, SASS, and ESLint

March 29, 2020  9 minute read  

create-react-app (CRA) is great for getting started super-fast. It has just about everything you need for building all but the most demanding apps. It is, however, opinionated in how things get set up, and I’ve been chafing at the limitations for a while. You can’t alter the tsconfig.json except in some non-important ways. It uses webpack underneath, and that is unchangeable. It uses jest and testing-library. Changing this is a pain. There are even packages that rewire the CRA so...

Integrating Microsoft Login and MSAL with React and Redux

March 06, 2020  9 minute read  

I have a new app I am working on. It’s sort of a 1990’s style text MUD, but I’m bringing it “up to this century” with a host of new features. I’m writing the first front-end in React. So, what does a modern MUD app look like? Well, I’m not into storing usernames and password any more, so I’m going to use a Microsoft OAuth service instead of a user database. My front end application handles state through Redux. Configuring Redux I’ve got a store set up as follows: import { applyMiddlew...

Pre-build steps for Flutter using Visual Studio Code

February 20, 2020  2 minute read  

Flutter is not a build system. I know, it’s a terrible way to start, but you have to accept that you need to produce a build system for Flutter. There are build systems written in Dart (such as this one), and I’m sure this situation will get better, but right now? There isn’t a good build system. So I use the node package manager. Here is my basic flow: Run npm init -y. Edit the produced package.json file to use flutter under the covers. Run flutter with npm start instead of the ...

Adding a pre-build step to Android Studio builds

January 20, 2020  2 minute read  

I’m currently writing a cloud-native app with an Android (and iOS) front end. I’ve got my backend configuration written using Terraform, and it outputs a file called infrastructure.json that describes the backend in a JSON format. Now, the question becomes “how do I get that infrastructure.json file into my front end code?” A simple version of this would be to ensure I copy the file every single time I update it. However, a better solution would be to ensure the file exists and to copy it...

Reducing the deployment size of your JavaScript Azure Functions

January 12, 2020  1 minute read  

I’m doing some Azure Functions development in JavaScript at the moment, using the new azure-functions-core-tools. One of the features it has is command line publication, like this: $ func azure functionapp publish my-function-app I have a single function right now (called ping). Running the publish step creates a ZIP file: $ npx func azure functionapp publish my-function-app Getting site publishing info... Creating archive for current directory... Uploading 187.62 MB [##--...

Mocking Android resources with Mockito and Kotlin

January 03, 2020  3 minute read  

I bumped into an issue that was a little harder than I expected to solve, so this is the documentation. Requirement: Load a JSON file from the res/raw resource directory. Actually, that wasn’t the problem. The problem was how do you test that functionality? The library I have a basic configuration library that is constructed like this: class Configuration internal constructor(jsonContext: String): Map<String, Any> { internal constructor(stream: InputStream) : this(stream.buf...

Unit testing asynchronous Android network libraries

January 01, 2020  5 minute read  

I’m writing a network library for Android at the moment, and specifically looking at unit tests. In my last article, I looking at mocking the Android context and other Android specific libraries. Since I am writing a network client library, I need to go a step further and deal with the network connection itself. How can I test the asynchronous network calls in a repeatable manner? Fortunately, there’s a library for that. Square, the same people that brought you OkHttp, also produce a moc...

Two tips for unit testing Android libraries

December 24, 2019  3 minute read  

I’m busy writing a networking library for one of my Android apps. The question today is “how do I properly test the library?” There are a few problem areas, and I’ll cover two of them today. How do I properly mock classes that aren’t really Android specific, like android.location.Location and android.net.Uri? How do I properly mock the Android context? Android Studio already integrates the excellent JUnit packages for unit testing. I don’t want to have to write a visual app just to...

Build a better RecyclerView Adapter

December 13, 2019  3 minute read  

Many of my Android apps end up including listst, which are implemented via a RecyclerView. More importantly, I know all the items in the list ahead of time. Every single blog and tutorial always uses the same methodology. This ends up being a lot of boilerplate code. Create a view holder class Create a list adapter Attach the list adapter to the recyclerview Update the view holder class to implement the UI Check out the requirements around clicking Arrange for the list of item...