This folder contains a dart:ui application and scripts to compile it to JIT or AOT for exercising embedders.
It intentionally has no dependencies on the Flutter framework or tooling, such that it should be buildable as a presubmit or postsubmit to the engine even in the face of changes to Dart or dart:ui that require upstream changes in the Flutter tooling.
cd ${ENGINE_REPO}/.. gclient sync ./flutter/tools/gn --unoptimized --runtime-mode debug --simulator --ios ninja -C out/ios_debug_sim_unopt cd ${ENGINE_REPO}/testing/scenario_app ./run_ios_tests.sh
Create a new subclass of Scenario and add it to the map in main.dart. For an example, see animated_color_square.dart, which draws a continuously animating colored square that bounces off the sides of the viewport.
For PlatformView tests on iOS, you‘ll also have to edit the dictionaries in AppDelegate.m and PlatformViewGoldenTestManager.m so that the correct golden image can be found. Also, you’ll have to add a GoldenPlatformViewTests in PlatformViewUITests.m.
Screenshots are saved as XCTAttachment‘s. If you look at the output from running the tests you’ll find a path in the form: /Users/$USER/Library/Developer/Xcode/DerivedData/Scenarios-$HASH. Inside that directory you'll find ./Build/Products/Debug-iphonesimulator/ScenariosUITests-Runner.app/PlugIns/ScenariosUITests.xctest/ which is where all the images that were compared against golden reside.
In this folder, after building the ios_host and ios_profile engine targets, run:
./compile_ios_aot.sh ../../../out/host_profile ../../../out/ios_profile/clang_x64/
This will create an App.framework copy it as well as the correct Flutter.framework to where the Xcode project expects to find them.
You can then use xcodebuild to build the ios/Scenarios/Scenarios.xcodeproj, or open that in Xcode and build it that way.
Compiling to JIT mode is similar, using the compile_ios_jit.sh script.
In this folder, after building the host_profile and android_profile_arm64 engine targets, run:
./compile_android_aot.sh ../../../out/host_profile ../../../out/android_profile_arm64/clang_x64/
This will produce a suitable libapp.so for building with an Android app and copy it (along with flutter.jar) to where Gradle will expect to find it to build the app in the android/ folder. The app can be run by opening it in Android Studio and running it, or by running ./gradlew assemble in the android/ folder and installing the APK from the correct folder in android/app/build/outputs/apk.
If you change the dart:ui interface, remember to point the sky_engine and sky_services clauses to your local engine's output path before compiling.