Skip to main content

Implementing UI tests on iOS and Android using screenshot comparison tools

Have you ever thought when writing or maintaining UI tests, there must be a better way?

Take a look at screenshot tests provided by Google Firebase and Facebook:

ios-snapshot-test-case
A "snapshot test case" takes a configured UIView or CALayer and uses the renderInContext: method to get an image snapshot of its contents. It compares this snapshot to a "reference image" stored in your source code repository and fails the test if the two images don't match.

GitHub Facebook

screenshot-tests-for-android
Testing rendering for your Android app is hard. How do you prevent visual regressions in paddings and margins and colors from creeping in?
Iterating on UI code is hard. How do you quickly verify that your layout or view changes work correctly in all configurations?

screenshot-tests-for-android can solve these problems by providing a test framework that checks for visual differences across changes.

GitHub Facebook

Google Firebase Test Lab
Test Lab lets you run Espresso, Robotium, or UI Automator 2.0 instrumentation tests written to exercise your app from the Firebase console, Android Studio, or the gcloud command line interface. You can also use Robo test to automatically exercise your app from the Firebase console or the gcloud command line.


Robo test captures logs, creates an "activity map" that shows a related set of annotated screenshots, and creates a video from a sequence of screenshots to show you the simulated user operations that it performed. Learn more about Robo test.

Firebase Test Lab

Firebase Test Lab for Android includes a library that you can use to take screenshots when running instrumentation tests, such as tests written using the Espresso test framework. To add this capability to your test, use the cloudtestingscreenshotter_lib.aar library.

The ability to take screenshots is already incorporated into the test APK, app-debug-test-unaligned.apk, for the NotePad sample app, and screenshots are also captured when you run Robo test. The following instructions tell you how to add the screenshot library to your app and how to call that library from your test.

After your test has run, you can review the screenshots in Android Studio or in the Firebase console.
Screenshot comparison screen

Firebase Take Screenshots

PointFree SnapShotTesting with Swift!

Comments

Most Favorite Posts

Server-driven UI (SDUI): Meet Zalandos AppCraft and AirBnB Lona

A short WTF: Joe Birch:  SERVER DRIVEN UI, PART 1: THE CONCEPT Zalando seems to follow the SDUI principle as well - defining a common design language and construct the screens on the backend while displaying them natively on the clients. They even go one step further; they implemented a mighty toolset to enable non-technical stakeholders to define their own native app screens Compass: Web tooling to create screens and bind data Beetroot: Backend service that combines the screen layout definition with the data Lapis/Golem: iOS/Android UI render engines Crazy cool! Good job, guys (when you do an open-source release?) To even move faster a Flutter based UI render engine implementation was great! See also AirBnB Lona SDUI approach Building a Visual Language Why Dropbox sunsetted its universal C++ mobile project and AirBnB its React Native implementation

Speed up your unit tests! Swap out your App Delegate for testing.

Faster, please One thing that can slow our tests down is if our App performs expensive tasks on startup and it is not unusual to place code that synchronizes with a server in our implementation of UIAppDelegate. Luckily for us there is a way to change the production App Delegate with a fake that does nothing. Objective-C class FakeAppDelegate: UIResponder, UIApplicationDelegate {   var window: UIWindow?   func application(application: UIApplication,     didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool {     self.window?.rootViewController = UIViewController()     return true   } } let isRunningTests = NSClassFromString("XCTestCase") != nil if isRunningTests {   UIApplicationMain(Process.argc, Process.unsafeArgv, nil,     NSStringFromClass(FakeAppDelegate)) } else {   UIApplicationMain(Process.argc, Process.unsafeArgv, nil,     NSStringFromClass(AppDelegate)) ...

Titanium: Releasing Memory

- It’s true that you can’t manually manage your application objects’ reference count in iOS applications. There are, however, things you can do to free up memory – the big ones in the 1.x product are closing windows (which releases all UI resources associated with the window) and setting references to a proxy object (like one returned by Ti.UI.createXXX) to null, which will release the resources associated with that object. Why you should stay away from Titanium

Leveraging your iPhone development expertise to build Windows Phone 7 applications

Assuming you are a happy coder, the joy of developing software all comes down to a few things: Building something cool that users will enjoy Getting rewards from users and recognition from peers Learning how to solve new challenges and build novel features. Even if you have a solid expertise on a particular platform/language, I think it is essential to be a “polyglot” developer. In other words, you might have a native or preferred language, but opening your mind to others can be very stimulating and will bring considerable value to your abilities and your resume. Jumping from one platform or language to another can introduce breaking changes in your habits, but ultimately change is very stimulating and will expand your opportunities. If you are a .NET developer, learning Windows Phone development is not really “change.” Instead, it is more of a continuum, where you just add new features to what you already know. If you are an iPhone developer, new to Windows Phone (and .NET), ...

CouchDB for iOS

A build of Apache CouchDB optimized for iPad, iPhone, and iPod Touch iOS-Couchbase CouchDB - Key Features Documents Views Schema-Free Distributed CouchDB is a peer based distributed database system. Any number of CouchDB hosts (servers and offline-clients) can have independent “replica copies” of the same database, where applications have full database interactivity (query, add, edit, delete). When back online or on a schedule, database changes are replicated bi-directionally. CouchDB has built-in conflict detection and management and the replication process is incremental and fast, copying only documents and individual fields changed since the previous replication. Most applications require no special planning to take advantage of distributed updates and replication. CouchDB

Employee Development ...by Cards ...by Lego Brick Boards

Employee Development by using Skill Cards The goal is to build a hand of cards that make up that person’s most relevant personal growth areas. To do this, both the people leader and team member start with a deck of the same skill cards each. In private, each goes through this deck and sorts these cards into three stacks: not relevant, good enough, and to improve. By discussing why each card was placed where, with particular focus on those that do not match, a real, structured, and to-the-point conversation occurs. By focusing on reasoning—what led you to place this card here?—both can develop a shared understanding of the other's views. The main event, however, comes in focusing on those cards in “to improve”. To create focus and drive actual impact, these cards are discussed and prioritized. With a clear priority and a shared understanding of the individual aspects of each, tangible actions are crafted that can be taken to grow one’s career. LinkedIn Rob Sawyer mobi...