Category: tech
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Async Let Bindings: a Gotcha and a Closer Look
Swift 5.5 introduced a powerful set of concurrency tools to deal with asynchronous tasks, eliminating the complexity of callbacks and queues. Besides Task and TaskGroup for managing child tasks, the async let syntax allows you to start concurrent tasks and bind their results to variables, following structured concurrency principles. Yet, be cautious when writing async let bindings. Consider these two declarations below. async let x = taskX() // returns an Int async let y = taskY() // retunns a String let result = await (x, y) async let (x, y) = (taskX(), taskY()) let result = await (x, y) At first glance, they seem equivalent.
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In Search of Test Discovery Solutions in iOS
Introduction Five years ago, I wrote a blog post about extracting test methods before runtime in iOS. This falls under a broader category of test discovery - the process of identifying test cases in a codebase. While test discovery is relatively straightforward in scripting languages, it is more challenging in iOS and other statically typed languages. For a Swift package project, this can be done with the swift test list command.
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Swift Testing and the Compatibility With xcodebuild
Introduction Swift Testing is a new test framework introduced by Apple at WWDC 2024. It offers a range of macro-based features, making test writing more expressive. One of the key features driving migration from XCTest to Swift Testing is parameterized testing. While this concept has been widely available in other languages (ex. pytest introduced it in 2011), Swift Testing now enables repeated test execution with different inputs and expected outputs.
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Automation at Your Core
We often hear that automating repetitive tasks improves productivity. But how do we decide when automation is truly worth the effort? 1 At OKX, while managing end-to-end testing servers, I frequently needed to SSH into servers to diagnose issues and retrieve relevant logs (to my local) for further investigations. This was tedious but manageable, thanks to my terminal’s auto-completion. However, as we expanded to four servers (two in Hong Kong, two in Singapore), keeping track of server IPs, usernames and passwords for the SSH became a hassle.
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WebDriverAgent - The Heart of iOS E2E Testing
In the previous post, we explored the overview of E2E testing in mobile development. Today, we’re going to dive deeper into how E2E testing with Appium works on iOS. 1. Introduction to WebDriverAgent (WDA) 1.1. Running Your First Test With Appium Here’s a simple code snippet to start your tests. For simplicity, we’ll run tests on simulators.
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Overview of Mobile E2E Testing
1. Introduction End-to-end (E2E) testing is a software testing strategy that verifies the system integration from start to finish, including apps, backend services, and other related components; to ensure everything functions as expected altogether. Compared to unit tests, E2E tests are often fewer in number due to their complexity and maintenance costs. This type of testing is even more uncommon in mobile development where special setups are often required. This blog post aims to provide a quick overview of mobile E2E testing and some opinionated architecture suggestions for incorporating E2E testing into your engineering process.
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How Xcode Recognizes Module Imports
In iOS development, a module is a self-contained unit of code offering a specific set of functionalities. Modules help break down complex apps into smaller components. Developers can incorporate a module into different parts of an app using the import keyword. Behind the scenes, the build system performs several tasks to recognize and integrate these imports seamlessly. A module can be distributed in various formats such as collections of source files, or a pre-compiled binaries or bundles.
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pre-commit Environment Issue in SourceTree
In the previous post, I mentioned pre-commit as a powerful tool to lint and format in a project. It had worked seamlessly for me until I committed code using SourceTree. Just to clarify, I predominantly use git on terminal. I only use a GUI app such as SourceTree to view the diff, or to stage selective chunks in a file (which is a bit difficult to achieve when using terminal). Therefore, the issue went unnoticed during my usual workflow.
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Using pre-commit for Linters/Formatters
During my tenure at Grab, I witnessed the project’s transformation from an iOS exclusive to a multi-language initiative. Initially, the project primarily comprised iOS code. Over time, we developed various scripts (Ruby, Python, Bash, etc.) to enhance project build time and facilitate CI/CD integration. However, the linter setup was not sufficient for such a multi-language project. At a glance, we used SwiftLint, Rubocop, and Flake8 to lint Swift, Ruby, and Python code, respectively.
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Using Swift Packages in CocoaPods-Based Projects
1. Introduction Swift Package Manager (SwiftPM, or SPM) is a tool for managing the distribution of Swift code. Initially launched in 2015, it primarily catered to server-side or command-like projects. Its adoption has been limited over the years due to lack of support for the mainstream iOS/MacOS development. During this time, CocoaPods has gained its power and emerged as a dominant tool in iOS development. Not until recently has SPM been adopted widely.