Compose Multiplatform UI Testing Demo

This repository is the official companion code for the article: "Clean Lap: UI Testing in Compose Multiplatform".

It serves as a practical implementation of a unified testing strategy, demonstrating how to write UI tests once in commonTest and execute them across Android, iOS, and Desktop targets.

📖 What This Demo Covers

This project showcases several advanced Compose Multiplatform concepts discussed in the article:

• Unified UI Testing: Leveraging the ComposeUiTest API to run the same test suite across all supported platforms.
• Asynchronous Testing: Implementing waitUntil and semantic node polling to handle LaunchedEffect and Coroutine-driven state changes (see FeedScreenTest.kt).
• Shared Architecture: A clean, multiplatform implementation of ViewModel and StateFlow using Jetpack Lifecycle.
• Navigation & State: A simple but effective screen switching mechanism (Home -> Login -> Feed) managed within the shared source set.

🛠 Tech Stack

• Framework: Compose Multiplatform
• Architecture: Jetpack ViewModel (shared in commonMain)
• Testing: Compose UI Test API (v2)
• Concurrency: Kotlinx Coroutines

🚀 Getting Started

Prerequisites

• Android Studio Koala (or newer)
• JDK 17
• Xcode (for iOS testing/running)

Running the Application

• Android: Run the composeApp configuration.
• Desktop: Execute ./gradlew :composeApp:run
• iOS: Open iosApp/iosApp.xcworkspace in Xcode.

🧪 Running the Tests

The core value of this repository is the shared testing suite located in composeApp/src/commonTest.

Desktop (JVM)

./gradlew :composeApp:test

Android (Instrumented)

./gradlew :composeApp:connectedDebugAndroidTest

Example: Testing Async Loading

@Test
fun feedScreen_showsLoadingThenContent() = runComposeUiTest {
    // ... initial loading state check ...
    
    // Explicitly wait for the list to appear after async load
    waitUntil(timeoutMillis = 1000) {
        onAllNodesWithTag("feed_list").fetchSemanticsNodes().isNotEmpty()
    }
}

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For the full breakdown of how this was built, read the complete article on KMP Bits.