Add iOS platform view mutation XCUITests to the scenario app (flutter/engine#11652)

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -252,7 +252,8 @@ UIView* FlutterPlatformViewsController::ReconstructClipViewsChain(int number_of_
   }
   // If there were not enough existing clip views, add more.
   while (clipIndex < number_of_clips) {
-    ChildClippingView* clippingView = [ChildClippingView new];
+    ChildClippingView* clippingView =
+        [[ChildClippingView alloc] initWithFrame:flutter_view_.get().bounds];
     [clippingView addSubview:head];
     head = clippingView;
     clipIndex++;

engine/src/flutter/testing/scenario_app/android/app/src/main/java/io/flutter/plugins/GeneratedPluginRegistrant.java

@@ -0,0 +1,23 @@
+package io.flutter.plugins;
+
+import io.flutter.plugin.common.PluginRegistry;
+
+/**
+ * Generated file. Do not edit.
+ */
+public final class GeneratedPluginRegistrant {
+  public static void registerWith(PluginRegistry registry) {
+    if (alreadyRegisteredWith(registry)) {
+      return;
+    }
+  }
+
+  private static boolean alreadyRegisteredWith(PluginRegistry registry) {
+    final String key = GeneratedPluginRegistrant.class.getCanonicalName();
+    if (registry.hasPlugin(key)) {
+      return true;
+    }
+    registry.registrarFor(key);
+    return false;
+  }
+}

engine/src/flutter/testing/scenario_app/ios/Runner/GeneratedPluginRegistrant.h

@@ -0,0 +1,14 @@
+//
+//  Generated file. Do not edit.
+//
+
+#ifndef GeneratedPluginRegistrant_h
+#define GeneratedPluginRegistrant_h
+
+#import <Flutter/Flutter.h>
+
+@interface GeneratedPluginRegistrant : NSObject
++ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry;
+@end
+
+#endif /* GeneratedPluginRegistrant_h */

engine/src/flutter/testing/scenario_app/ios/Runner/GeneratedPluginRegistrant.m

@@ -0,0 +1,12 @@
+//
+//  Generated file. Do not edit.
+//
+
+#import "GeneratedPluginRegistrant.h"
+
+@implementation GeneratedPluginRegistrant
+
++ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry {
+}
+
+@end

engine/src/flutter/testing/scenario_app/ios/Scenarios/Scenarios.xcodeproj/project.pbxproj

@@ -30,6 +30,14 @@
 		24D47D1B230C79840069DD5E /* golden_platform_view_D211AP.png in Resources */ = {isa = PBXBuildFile; fileRef = 24D47D1A230C79840069DD5E /* golden_platform_view_D211AP.png */; };
 		24D47D1D230CA2700069DD5E /* golden_platform_view_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 24D47D1C230CA2700069DD5E /* golden_platform_view_iPhone SE_simulator.png */; };
 		24F1FB89230B4579005ACE7C /* TextPlatformView.m in Sources */ = {isa = PBXBuildFile; fileRef = 24F1FB87230B4579005ACE7C /* TextPlatformView.m */; };
+		6816DB9E231750ED00A51400 /* GoldenPlatformViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 6816DB9D231750ED00A51400 /* GoldenPlatformViewTests.m */; };
+		6816DBA12317573300A51400 /* GoldenImage.m in Sources */ = {isa = PBXBuildFile; fileRef = 6816DBA02317573300A51400 /* GoldenImage.m */; };
+		6816DBA42318358200A51400 /* PlatformViewGoldenTestManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 6816DBA32318358200A51400 /* PlatformViewGoldenTestManager.m */; };
+		6816DBAA2318696600A51400 /* golden_platform_view_clippath_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6816DBA52318696600A51400 /* golden_platform_view_clippath_iPhone SE_simulator.png */; };
+		6816DBAB2318696600A51400 /* golden_platform_view_transform_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6816DBA62318696600A51400 /* golden_platform_view_transform_iPhone SE_simulator.png */; };
+		6816DBAC2318696600A51400 /* golden_platform_view_opacity_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6816DBA72318696600A51400 /* golden_platform_view_opacity_iPhone SE_simulator.png */; };
+		6816DBAD2318696600A51400 /* golden_platform_view_cliprect_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6816DBA82318696600A51400 /* golden_platform_view_cliprect_iPhone SE_simulator.png */; };
+		6816DBAE2318696600A51400 /* golden_platform_view_cliprrect_iPhone SE_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6816DBA92318696600A51400 /* golden_platform_view_cliprrect_iPhone SE_simulator.png */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -113,6 +121,17 @@
 		24D47D1E230CA4480069DD5E /* README.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = "<group>"; };
 		24F1FB87230B4579005ACE7C /* TextPlatformView.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = TextPlatformView.m; sourceTree = "<group>"; };
 		24F1FB88230B4579005ACE7C /* TextPlatformView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = TextPlatformView.h; sourceTree = "<group>"; };
+		6816DB9C231750ED00A51400 /* GoldenPlatformViewTests.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = GoldenPlatformViewTests.h; sourceTree = "<group>"; };
+		6816DB9D231750ED00A51400 /* GoldenPlatformViewTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = GoldenPlatformViewTests.m; sourceTree = "<group>"; };
+		6816DB9F2317573300A51400 /* GoldenImage.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = GoldenImage.h; sourceTree = "<group>"; };
+		6816DBA02317573300A51400 /* GoldenImage.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = GoldenImage.m; sourceTree = "<group>"; };
+		6816DBA22318358200A51400 /* PlatformViewGoldenTestManager.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = PlatformViewGoldenTestManager.h; sourceTree = "<group>"; };
+		6816DBA32318358200A51400 /* PlatformViewGoldenTestManager.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = PlatformViewGoldenTestManager.m; sourceTree = "<group>"; };
+		6816DBA52318696600A51400 /* golden_platform_view_clippath_iPhone SE_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_clippath_iPhone SE_simulator.png"; sourceTree = "<group>"; };
+		6816DBA62318696600A51400 /* golden_platform_view_transform_iPhone SE_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_transform_iPhone SE_simulator.png"; sourceTree = "<group>"; };
+		6816DBA72318696600A51400 /* golden_platform_view_opacity_iPhone SE_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_opacity_iPhone SE_simulator.png"; sourceTree = "<group>"; };
+		6816DBA82318696600A51400 /* golden_platform_view_cliprect_iPhone SE_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_cliprect_iPhone SE_simulator.png"; sourceTree = "<group>"; };
+		6816DBA92318696600A51400 /* golden_platform_view_cliprrect_iPhone SE_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_cliprrect_iPhone SE_simulator.png"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -200,9 +219,20 @@
 				244EA6CF230DBE8900B2D26E /* golden_platform_view_D21AP.png */,
 				24D47D1C230CA2700069DD5E /* golden_platform_view_iPhone SE_simulator.png */,
 				24D47D1A230C79840069DD5E /* golden_platform_view_D211AP.png */,
+				6816DBA52318696600A51400 /* golden_platform_view_clippath_iPhone SE_simulator.png */,
+				6816DBA82318696600A51400 /* golden_platform_view_cliprect_iPhone SE_simulator.png */,
+				6816DBA92318696600A51400 /* golden_platform_view_cliprrect_iPhone SE_simulator.png */,
+				6816DBA72318696600A51400 /* golden_platform_view_opacity_iPhone SE_simulator.png */,
+				6816DBA62318696600A51400 /* golden_platform_view_transform_iPhone SE_simulator.png */,
 				248D76EE22E388380012F0C1 /* PlatformViewUITests.m */,
 				248D76F022E388380012F0C1 /* Info.plist */,
 				24D47D1E230CA4480069DD5E /* README.md */,
+				6816DB9C231750ED00A51400 /* GoldenPlatformViewTests.h */,
+				6816DB9D231750ED00A51400 /* GoldenPlatformViewTests.m */,
+				6816DB9F2317573300A51400 /* GoldenImage.h */,
+				6816DBA02317573300A51400 /* GoldenImage.m */,
+				6816DBA22318358200A51400 /* PlatformViewGoldenTestManager.h */,
+				6816DBA32318358200A51400 /* PlatformViewGoldenTestManager.m */,
 			);
 			path = ScenariosUITests;
 			sourceTree = "<group>";
@@ -340,9 +370,14 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				6816DBAE2318696600A51400 /* golden_platform_view_cliprrect_iPhone SE_simulator.png in Resources */,
+				6816DBAB2318696600A51400 /* golden_platform_view_transform_iPhone SE_simulator.png in Resources */,
+				6816DBAA2318696600A51400 /* golden_platform_view_clippath_iPhone SE_simulator.png in Resources */,
+				6816DBAD2318696600A51400 /* golden_platform_view_cliprect_iPhone SE_simulator.png in Resources */,
 				24D47D1B230C79840069DD5E /* golden_platform_view_D211AP.png in Resources */,
 				24D47D1D230CA2700069DD5E /* golden_platform_view_iPhone SE_simulator.png in Resources */,
 				244EA6D0230DBE8900B2D26E /* golden_platform_view_D21AP.png in Resources */,
+				6816DBAC2318696600A51400 /* golden_platform_view_opacity_iPhone SE_simulator.png in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -375,6 +410,9 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				6816DBA12317573300A51400 /* GoldenImage.m in Sources */,
+				6816DB9E231750ED00A51400 /* GoldenPlatformViewTests.m in Sources */,
+				6816DBA42318358200A51400 /* PlatformViewGoldenTestManager.m in Sources */,
 				248D76EF22E388380012F0C1 /* PlatformViewUITests.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

engine/src/flutter/testing/scenario_app/ios/Scenarios/Scenarios/AppDelegate.m

@@ -25,27 +25,55 @@
 
   // This argument is used by the XCUITest for Platform Views so that the app
   // under test will create platform views.
-  if ([[[NSProcessInfo processInfo] arguments] containsObject:@"--platform-view"]) {
-    FlutterEngine* engine = [[FlutterEngine alloc] initWithScenario:@"text_platform_view"
-                                                     withCompletion:nil];
-    [engine runWithEntrypoint:nil];
+  // The launchArgsMap should match the one in the `PlatformVieGoldenTestManager`.
+  NSDictionary<NSString*, NSString*>* launchArgsMap = @{
+    @"--platform-view" : @"platform_view",
+    @"--platform-view-cliprect" : @"platform_view_cliprect",
+    @"--platform-view-cliprrect" : @"platform_view_cliprrect",
+    @"--platform-view-clippath" : @"platform_view_clippath",
+    @"--platform-view-transform" : @"platform_view_transform",
+    @"--platform-view-opacity" : @"platform_view_opacity",
+  };
+  __block NSString* goldenTestName = nil;
+  [launchArgsMap
+      enumerateKeysAndObjectsUsingBlock:^(NSString* argument, NSString* testName, BOOL* stop) {
+        if ([[[NSProcessInfo processInfo] arguments] containsObject:argument]) {
+          goldenTestName = testName;
+          *stop = YES;
+        }
+      }];
 
-    FlutterViewController* flutterViewController =
-        [[NoStatusBarFlutterViewController alloc] initWithEngine:engine nibName:nil bundle:nil];
-    TextPlatformViewFactory* textPlatformViewFactory =
-        [[TextPlatformViewFactory alloc] initWithMessenger:flutterViewController.binaryMessenger];
-    NSObject<FlutterPluginRegistrar>* registrar =
-        [flutterViewController.engine registrarForPlugin:@"scenarios/TextPlatformViewPlugin"];
-    [registrar registerViewFactory:textPlatformViewFactory withId:@"scenarios/textPlatformView"];
-    self.window.rootViewController = flutterViewController;
+  if (goldenTestName) {
+    [self readyContextForPlatformViewTests:goldenTestName];
   } else if ([[[NSProcessInfo processInfo] arguments] containsObject:@"--screen-before-flutter"]) {
     self.window.rootViewController = [[ScreenBeforeFlutter alloc] initWithEngineRunCompletion:nil];
   } else {
     self.window.rootViewController = [[UIViewController alloc] init];
   }
-  [self.window makeKeyAndVisible];
 
+  [self.window makeKeyAndVisible];
   return [super application:application didFinishLaunchingWithOptions:launchOptions];
 }
 
+- (void)readyContextForPlatformViewTests:(NSString*)scenarioIdentifier {
+  FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"PlatformViewTest" project:nil];
+  [engine runWithEntrypoint:nil];
+
+  FlutterViewController* flutterViewController =
+      [[NoStatusBarFlutterViewController alloc] initWithEngine:engine nibName:nil bundle:nil];
+  [engine.binaryMessenger
+      setMessageHandlerOnChannel:@"scenario_status"
+            binaryMessageHandler:^(NSData* _Nullable message, FlutterBinaryReply _Nonnull reply) {
+              [engine.binaryMessenger
+                  sendOnChannel:@"set_scenario"
+                        message:[scenarioIdentifier dataUsingEncoding:NSUTF8StringEncoding]];
+            }];
+  TextPlatformViewFactory* textPlatformViewFactory =
+      [[TextPlatformViewFactory alloc] initWithMessenger:flutterViewController.binaryMessenger];
+  NSObject<FlutterPluginRegistrar>* registrar =
+      [flutterViewController.engine registrarForPlugin:@"scenarios/TextPlatformViewPlugin"];
+  [registrar registerViewFactory:textPlatformViewFactory withId:@"scenarios/textPlatformView"];
+  self.window.rootViewController = flutterViewController;
+}
+
 @end

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenImage.h

@@ -0,0 +1,26 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <UIKit/UIKit.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface GoldenImage : NSObject
+
+@property(readonly, copy, nonatomic) NSString* goldenName;
+@property(readonly, strong, nonatomic) UIImage* image;
+
+// Initilize with the golden file's prefix.
+//
+// Create an image from a golden file named prefix+devicemodel.
+- (instancetype)initWithGoldenNamePrefix:(NSString*)prefix;
+
+// Compare this GoldenImage to `image`.
+//
+// Return YES if the `image` of this GoldenImage have the same pixels of provided `image`.
+- (BOOL)compareGoldenToImage:(UIImage*)image;
+
+@end
+
+NS_ASSUME_NONNULL_END

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenImage.m

@@ -0,0 +1,94 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "GoldenImage.h"
+#import <XCTest/XCTest.h>
+#include <sys/sysctl.h>
+
+@interface GoldenImage ()
+
+@end
+
+@implementation GoldenImage
+
+- (instancetype)initWithGoldenNamePrefix:(NSString*)prefix {
+  self = [super init];
+  if (self) {
+    _goldenName = [prefix stringByAppendingString:_platformName()];
+    NSBundle* bundle = [NSBundle bundleForClass:[self class]];
+    NSURL* goldenURL = [bundle URLForResource:_goldenName withExtension:@"png"];
+    NSData* data = [NSData dataWithContentsOfURL:goldenURL];
+    _image = [[UIImage alloc] initWithData:data];
+  }
+  return self;
+}
+
+- (BOOL)compareGoldenToImage:(UIImage*)image {
+  if (!self.image || !image) {
+    return NO;
+  }
+  CGImageRef imageRefA = [self.image CGImage];
+  CGImageRef imageRefB = [image CGImage];
+
+  NSUInteger widthA = CGImageGetWidth(imageRefA);
+  NSUInteger heightA = CGImageGetHeight(imageRefA);
+  NSUInteger widthB = CGImageGetWidth(imageRefB);
+  NSUInteger heightB = CGImageGetHeight(imageRefB);
+
+  if (widthA != widthB || heightA != heightB) {
+    return NO;
+  }
+  NSUInteger bytesPerPixel = 4;
+  NSUInteger size = widthA * heightA * bytesPerPixel;
+  NSMutableData* rawA = [NSMutableData dataWithLength:size];
+  NSMutableData* rawB = [NSMutableData dataWithLength:size];
+
+  if (!rawA || !rawB) {
+    return NO;
+  }
+
+  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+
+  NSUInteger bytesPerRow = bytesPerPixel * widthA;
+  NSUInteger bitsPerComponent = 8;
+  CGContextRef contextA =
+      CGBitmapContextCreate(rawA.mutableBytes, widthA, heightA, bitsPerComponent, bytesPerRow,
+                            colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
+
+  CGContextDrawImage(contextA, CGRectMake(0, 0, widthA, heightA), imageRefA);
+  CGContextRelease(contextA);
+
+  CGContextRef contextB =
+      CGBitmapContextCreate(rawB.mutableBytes, widthA, heightA, bitsPerComponent, bytesPerRow,
+                            colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
+  CGColorSpaceRelease(colorSpace);
+
+  CGContextDrawImage(contextB, CGRectMake(0, 0, widthA, heightA), imageRefB);
+  CGContextRelease(contextB);
+
+  if (memcmp(rawA.mutableBytes, rawB.mutableBytes, size)) {
+    return NO;
+  }
+
+  return YES;
+}
+
+NS_INLINE NSString* _platformName() {
+  NSString* simulatorName =
+      [[NSProcessInfo processInfo].environment objectForKey:@"SIMULATOR_DEVICE_NAME"];
+  if (simulatorName) {
+    return [NSString stringWithFormat:@"%@_simulator", simulatorName];
+  }
+
+  size_t size;
+  sysctlbyname("hw.model", NULL, &size, NULL, 0);
+  char* answer = malloc(size);
+  sysctlbyname("hw.model", answer, &size, NULL, 0);
+
+  NSString* results = [NSString stringWithCString:answer encoding:NSUTF8StringEncoding];
+  free(answer);
+  return results;
+}
+
+@end

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenPlatformViewTests.h

@@ -0,0 +1,30 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <XCTest/XCTest.h>
+#import "PlatformViewGoldenTestManager.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+// The base class of all the PlatformView golden tests.
+//
+// A new PlatformView golden tests can subclass this and override the `-initiWithInvocation:`
+// method, which then retun the `-initWithManager:invocation:`
+//
+// Then in any test method, call `checkGolden` to perform the golden test.
+//
+// This base class doesn't run any test case on its own.
+@interface GoldenPlatformViewTests : XCTestCase
+
+// Initialize with a `PlatformViewGoldenTestManager`.
+- (instancetype)initWithManager:(PlatformViewGoldenTestManager*)manager
+                     invocation:(NSInvocation*)invocation;
+
+// Take a sceenshot of the test app and check it has the same pixels with goldenImage inside the
+// `PlatformViewGoldenTestManager`.
+- (void)checkGolden;
+
+@end
+
+NS_ASSUME_NONNULL_END

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenPlatformViewTests.m

@@ -0,0 +1,68 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "GoldenPlatformViewTests.h"
+#include <sys/sysctl.h>
+#import "PlatformViewGoldenTestManager.h"
+
+static const NSInteger kSecondsToWaitForPlatformView = 30;
+
+@interface GoldenPlatformViewTests ()
+
+@property(nonatomic, copy) NSString* goldenName;
+@property(nonatomic, strong) XCUIApplication* application;
+
+@property(nonatomic, strong) PlatformViewGoldenTestManager* manager;
+
+@end
+
+@implementation GoldenPlatformViewTests
+
+- (instancetype)initWithManager:(PlatformViewGoldenTestManager*)manager
+                     invocation:(NSInvocation*)invocation {
+  self = [super initWithInvocation:invocation];
+  _manager = manager;
+  return self;
+}
+
+- (void)setUp {
+  [super setUp];
+  self.continueAfterFailure = NO;
+
+  self.application = [[XCUIApplication alloc] init];
+  self.application.launchArguments = @[ self.manager.launchArg ];
+  [self.application launch];
+}
+
+// Note: don't prefix with "test" or GoldenPlatformViewTests will run instead of the subclasses.
+- (void)checkGolden {
+  XCUIElement* element = self.application.textViews.firstMatch;
+  BOOL exists = [element waitForExistenceWithTimeout:kSecondsToWaitForPlatformView];
+  if (!exists) {
+    XCTFail(@"It took longer than %@ second to find the platform view."
+            @"There might be issues with the platform view's construction,"
+            @"or with how the scenario is built.",
+            @(kSecondsToWaitForPlatformView));
+  }
+
+  GoldenImage* golden = self.manager.goldenImage;
+
+  XCUIScreenshot* screenshot = [[XCUIScreen mainScreen] screenshot];
+  XCTAttachment* attachment = [XCTAttachment attachmentWithScreenshot:screenshot];
+  attachment.lifetime = XCTAttachmentLifetimeKeepAlways;
+  [self addAttachment:attachment];
+
+  if (golden.image) {
+    XCTAttachment* goldenAttachment = [XCTAttachment attachmentWithImage:golden.image];
+    goldenAttachment.lifetime = XCTAttachmentLifetimeKeepAlways;
+    [self addAttachment:goldenAttachment];
+  } else {
+    XCTFail(@"This test will fail - no golden named %@ found. Follow the steps in the "
+            @"README to add a new golden.",
+            golden.goldenName);
+  }
+
+  XCTAssertTrue([golden compareGoldenToImage:screenshot.image]);
+}
+@end

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/PlatformViewGoldenTestManager.h

@@ -0,0 +1,29 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Foundation/Foundation.h>
+#import "GoldenImage.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+extern NSDictionary* launchArgsMap;
+
+// Manages a `GoldenPlatformViewTests`.
+//
+// It creates the correct `identifer` based on the `launchArg`.
+// It also generates the correct GoldenImage based on the `identifier`.
+@interface PlatformViewGoldenTestManager : NSObject
+
+@property(readonly, strong, nonatomic) GoldenImage* goldenImage;
+@property(readonly, copy, nonatomic) NSString* identifier;
+@property(readonly, copy, nonatomic) NSString* launchArg;
+
+// Initilize with launchArg.
+//
+// Crahes if the launchArg is not mapped in `Appdelegate.launchArgsMap`.
+- (instancetype)initWithLaunchArg:(NSString*)launchArg;
+
+@end
+
+NS_ASSUME_NONNULL_END

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/PlatformViewGoldenTestManager.m

@@ -0,0 +1,41 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "PlatformViewGoldenTestManager.h"
+
+@interface PlatformViewGoldenTestManager ()
+
+@property(readwrite, strong, nonatomic) GoldenImage* goldenImage;
+
+@end
+
+@implementation PlatformViewGoldenTestManager
+
+NSDictionary* launchArgsMap;
+
+- (instancetype)initWithLaunchArg:(NSString*)launchArg {
+  self = [super init];
+  if (self) {
+    // The launchArgsMap should match the one in the `PlatformVieGoldenTestManager`.
+    static NSDictionary<NSString*, NSString*>* launchArgsMap;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+      launchArgsMap = @{
+        @"--platform-view" : @"platform_view",
+        @"--platform-view-cliprect" : @"platform_view_cliprect",
+        @"--platform-view-cliprrect" : @"platform_view_cliprrect",
+        @"--platform-view-clippath" : @"platform_view_clippath",
+        @"--platform-view-transform" : @"platform_view_transform",
+        @"--platform-view-opacity" : @"platform_view_opacity",
+      };
+    });
+    _identifier = launchArgsMap[launchArg];
+    NSString* prefix = [NSString stringWithFormat:@"golden_%@_", _identifier];
+    _goldenImage = [[GoldenImage alloc] initWithGoldenNamePrefix:prefix];
+    _launchArg = launchArg;
+  }
+  return self;
+}
+
+@end

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/PlatformViewUITests.m

@@ -2,114 +2,113 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import <Flutter/flutter.h>
-#import <XCTest/XCTest.h>
-#include <sys/sysctl.h>
+#import "GoldenPlatformViewTests.h"
 
-#import "../Scenarios/TextPlatformView.h"
+@interface PlatformViewUITests : GoldenPlatformViewTests
 
-@interface PlatformViewUITests : XCTestCase
-@property(nonatomic, strong) XCUIApplication* application;
 @end
 
 @implementation PlatformViewUITests
 
-- (void)setUp {
-  [super setUp];
-  self.continueAfterFailure = NO;
-
-  self.application = [[XCUIApplication alloc] init];
-  self.application.launchArguments = @[ @"--platform-view" ];
-  [self.application launch];
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view"];
+  return [super initWithManager:manager invocation:invocation];
 }
 
 - (void)testPlatformView {
-  NSBundle* bundle = [NSBundle bundleForClass:[self class]];
-  NSString* goldenName =
-      [NSString stringWithFormat:@"golden_platform_view_%@", [self platformName]];
-  NSString* path = [bundle pathForResource:goldenName ofType:@"png"];
-  UIImage* golden = [[UIImage alloc] initWithContentsOfFile:path];
-
-  XCUIScreenshot* screenshot = [[XCUIScreen mainScreen] screenshot];
-  XCTAttachment* attachment = [XCTAttachment attachmentWithScreenshot:screenshot];
-  attachment.lifetime = XCTAttachmentLifetimeKeepAlways;
-  [self addAttachment:attachment];
-
-  if (golden) {
-    XCTAttachment* goldenAttachment = [XCTAttachment attachmentWithImage:golden];
-    goldenAttachment.lifetime = XCTAttachmentLifetimeKeepAlways;
-    [self addAttachment:goldenAttachment];
-  } else {
-    XCTFail(@"This test will fail - no golden named %@ found. Follow the steps in the "
-            @"README to add a new golden.",
-            goldenName);
-  }
-
-  XCTAssertTrue([self compareImage:golden toOther:screenshot.image]);
-}
-
-- (NSString*)platformName {
-  NSString* simulatorName =
-      [[NSProcessInfo processInfo].environment objectForKey:@"SIMULATOR_DEVICE_NAME"];
-  if (simulatorName) {
-    return [NSString stringWithFormat:@"%@_simulator", simulatorName];
-  }
-
-  size_t size;
-  sysctlbyname("hw.model", NULL, &size, NULL, 0);
-  char* answer = malloc(size);
-  sysctlbyname("hw.model", answer, &size, NULL, 0);
-
-  NSString* results = [NSString stringWithCString:answer encoding:NSUTF8StringEncoding];
-  free(answer);
-  return results;
-}
-
-- (BOOL)compareImage:(UIImage*)a toOther:(UIImage*)b {
-  CGImageRef imageRefA = [a CGImage];
-  CGImageRef imageRefB = [b CGImage];
-
-  NSUInteger widthA = CGImageGetWidth(imageRefA);
-  NSUInteger heightA = CGImageGetHeight(imageRefA);
-  NSUInteger widthB = CGImageGetWidth(imageRefB);
-  NSUInteger heightB = CGImageGetHeight(imageRefB);
-
-  if (widthA != widthB || heightA != heightB) {
-    return NO;
-  }
-  NSUInteger bytesPerPixel = 4;
-  NSUInteger size = widthA * heightA * bytesPerPixel;
-  NSMutableData* rawA = [NSMutableData dataWithLength:size];
-  NSMutableData* rawB = [NSMutableData dataWithLength:size];
-
-  if (!rawA || !rawB) {
-    return NO;
-  }
-
-  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
-
-  NSUInteger bytesPerRow = bytesPerPixel * widthA;
-  NSUInteger bitsPerComponent = 8;
-  CGContextRef contextA =
-      CGBitmapContextCreate(rawA.mutableBytes, widthA, heightA, bitsPerComponent, bytesPerRow,
-                            colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
-
-  CGContextDrawImage(contextA, CGRectMake(0, 0, widthA, heightA), imageRefA);
-  CGContextRelease(contextA);
-
-  CGContextRef contextB =
-      CGBitmapContextCreate(rawB.mutableBytes, widthA, heightA, bitsPerComponent, bytesPerRow,
-                            colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
-  CGColorSpaceRelease(colorSpace);
-
-  CGContextDrawImage(contextB, CGRectMake(0, 0, widthA, heightA), imageRefB);
-  CGContextRelease(contextB);
-
-  if (memcmp(rawA.mutableBytes, rawB.mutableBytes, size)) {
-    return NO;
-  }
-
-  return YES;
+  [self checkGolden];
+}
+
+@end
+
+// Clip Rect Tests
+@interface PlatformViewMutationClipRectTests : GoldenPlatformViewTests
+
+@end
+
+@implementation PlatformViewMutationClipRectTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view-cliprect"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkGolden];
+}
+
+@end
+
+@interface PlatformViewMutationClipRRectTests : GoldenPlatformViewTests
+
+@end
+
+@implementation PlatformViewMutationClipRRectTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view-cliprrect"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkGolden];
+}
+
+@end
+
+@interface PlatformViewMutationClipPathTests : GoldenPlatformViewTests
+
+@end
+
+@implementation PlatformViewMutationClipPathTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view-clippath"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkGolden];
+}
+
+@end
+
+@interface PlatformViewMutationTransformTests : GoldenPlatformViewTests
+
+@end
+
+@implementation PlatformViewMutationTransformTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view-transform"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkGolden];
+}
+
+@end
+
+@interface PlatformViewMutationOpacityTests : GoldenPlatformViewTests
+
+@end
+
+@implementation PlatformViewMutationOpacityTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  PlatformViewGoldenTestManager* manager =
+      [[PlatformViewGoldenTestManager alloc] initWithLaunchArg:@"--platform-view-opacity"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkGolden];
 }
 
 @end

engine/src/flutter/testing/scenario_app/lib/main.dart

@@ -16,7 +16,12 @@ import 'src/scenario.dart';
 
 Map<String, Scenario> _scenarios = <String, Scenario>{
   'animated_color_square': AnimatedColorSquareScenario(window),
-  'text_platform_view': PlatformViewScenario(window, 'Hello from Scenarios (Platform View)'),
+  'platform_view': PlatformViewScenario(window, 'Hello from Scenarios (Platform View)', id: 0),
+  'platform_view_cliprect': PlatformViewClipRectScenario(window, 'PlatformViewClipRect', id: 1),
+  'platform_view_cliprrect': PlatformViewClipRRectScenario(window, 'PlatformViewClipRRect', id: 2),
+  'platform_view_clippath': PlatformViewClipPathScenario(window, 'PlatformViewClipPath', id: 3),
+  'platform_view_transform': PlatformViewTransformScenario(window, 'PlatformViewTransform', id: 4),
+  'platform_view_opacity': PlatformViewOpacityScenario(window, 'PlatformViewOpacity', id: 5),
   'poppable_screen': PoppableScreenScenario(window),
 };
 

engine/src/flutter/testing/scenario_app/lib/src/platform_view.dart

@@ -4,8 +4,10 @@
 
 import 'dart:convert';
 import 'dart:io';
+import 'dart:math';
 import 'dart:typed_data';
 import 'dart:ui';
+import 'package:vector_math/vector_math_64.dart';
 
 import 'scenario.dart';
 
@@ -26,13 +28,147 @@ List<int> _to64(num value) {
 }
 
 /// A simple platform view.
-class PlatformViewScenario extends Scenario {
+class PlatformViewScenario extends Scenario
+    with _BasePlatformViewScenarioMixin {
   /// Creates the PlatformView scenario.
   ///
   /// The [window] parameter must not be null.
   PlatformViewScenario(Window window, String text, {int id = 0})
       : assert(window != null),
         super(window) {
+    constructScenario(window, text, id);
+  }
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    builder.pushOffset(0, 0);
+
+    finishBuilderByAddingPlatformViewAndPicture(builder, 0);
+  }
+}
+
+/// Platform view with clip rect.
+class PlatformViewClipRectScenario extends Scenario
+    with _BasePlatformViewScenarioMixin {
+  /// Constructs a platform view with clip rect scenario.
+  PlatformViewClipRectScenario(Window window, String text, {int id = 0})
+      : assert(window != null),
+        super(window) {
+    constructScenario(window, text, id);
+  }
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+    builder.pushOffset(0, 0);
+    builder.pushClipRect(const Rect.fromLTRB(100, 100, 400, 400));
+    finishBuilderByAddingPlatformViewAndPicture(builder, 1);
+  }
+}
+
+/// Platform view with clip rrect.
+class PlatformViewClipRRectScenario extends PlatformViewScenario {
+  /// Constructs a platform view with clip rrect scenario.
+  PlatformViewClipRRectScenario(Window window, String text, {int id = 0})
+      : super(window, text, id: id);
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    builder.pushOffset(0, 0);
+    builder.pushClipRRect(
+      RRect.fromLTRBAndCorners(
+        100,
+        100,
+        400,
+        400,
+        topLeft: const Radius.circular(15),
+        topRight: const Radius.circular(50),
+        bottomLeft: const Radius.circular(50),
+      ),
+    );
+    finishBuilderByAddingPlatformViewAndPicture(builder, 2);
+  }
+}
+
+/// Platform view with clip path.
+class PlatformViewClipPathScenario extends PlatformViewScenario {
+  /// Constructs a platform view with clip rrect scenario.
+  PlatformViewClipPathScenario(Window window, String text, {int id = 0})
+      : super(window, text, id: id);
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    builder.pushOffset(0, 0);
+
+    // Create a path of rectangle with width of 200 and height of 300, starting from (100, 100).
+    //
+    // Refer to "../../ios/Scenarios/Scenarios/ScenariosUITests/golden_platform_view_clippath_iPhone SE_simulator.png" for the exact path after clipping.
+    Path path = Path();
+    path.moveTo(100, 100);
+    path.quadraticBezierTo(50, 250, 100, 400);
+    path.lineTo(350, 400);
+    path.cubicTo(400, 300, 300, 200, 350, 100);
+    path.close();
+    builder.pushClipPath(path);
+
+    finishBuilderByAddingPlatformViewAndPicture(builder, 3);
+  }
+}
+
+/// Platform view with transform.
+class PlatformViewTransformScenario extends PlatformViewScenario {
+  /// Constructs a platform view with transform scenario.
+  PlatformViewTransformScenario(Window window, String text, {int id = 0})
+      : super(window, text, id: id);
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    builder.pushOffset(0, 0);
+    final Matrix4 matrix4 = Matrix4.identity()
+      ..rotateZ(1)
+      ..scale(0.5, 0.5, 1.0)
+      ..translate(1000.0, 100.0, 0.0);
+
+    builder.pushTransform(matrix4.storage);
+
+    finishBuilderByAddingPlatformViewAndPicture(builder, 4);
+  }
+}
+
+/// Platform view with opacity.
+class PlatformViewOpacityScenario extends PlatformViewScenario {
+  /// Constructs a platform view with transform scenario.
+  PlatformViewOpacityScenario(Window window, String text, {int id = 0})
+      : super(window, text, id: id);
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    builder.pushOffset(0, 0);
+    builder.pushOpacity(150);
+
+    finishBuilderByAddingPlatformViewAndPicture(builder, 5);
+  }
+}
+
+mixin _BasePlatformViewScenarioMixin on Scenario {
+  int _textureId;
+
+  /// Construct the platform view related scenario
+  ///
+  /// It prepare a TextPlatformView so it can be added to the SceneBuilder in `onBeginFrame`.
+  /// Call this method in the constructor of the platform view related scenarios
+  /// to perform necessary set up.
+  void constructScenario(Window window, String text, int id) {
     const int _valueInt32 = 3;
     const int _valueFloat64 = 6;
     const int _valueString = 7;
@@ -40,7 +176,7 @@ class PlatformViewScenario extends Scenario {
     const int _valueMap = 13;
     final Uint8List message = Uint8List.fromList(<int>[
       _valueString,
-      'create'.length, // this is safe as long as these are all single byte characters.
+      'create'.length, // this won't work if we use multi-byte characters.
       ...utf8.encode('create'),
       _valueMap,
       if (Platform.isIOS)
@@ -94,29 +230,27 @@ class PlatformViewScenario extends Scenario {
     );
   }
 
-  int _textureId;
-
-  @override
-  void onBeginFrame(Duration duration) {
-    final SceneBuilder builder = SceneBuilder();
-
-    builder.pushOffset(0, 0);
-
+  // Add a platform view and a picture to the scene, then finish the `sceneBuilder`.
+  void finishBuilderByAddingPlatformViewAndPicture(SceneBuilder sceneBuilder, int viewId) {
     if (Platform.isIOS) {
-      builder.addPlatformView(0, width: 500, height: 500);
+      sceneBuilder.addPlatformView(viewId, width: 500, height: 500);
     } else if (Platform.isAndroid && _textureId != null) {
-      builder.addTexture(_textureId, offset: const Offset(150, 300), width: 500, height: 500);
+      sceneBuilder.addTexture(_textureId,
+          offset: const Offset(150, 300), width: 500, height: 500);
     } else {
-      throw UnsupportedError('Platform ${Platform.operatingSystem} is not supported');
+      throw UnsupportedError(
+          'Platform ${Platform.operatingSystem} is not supported');
     }
-
     final PictureRecorder recorder = PictureRecorder();
     final Canvas canvas = Canvas(recorder);
-    canvas.drawCircle(const Offset(50, 50), 50, Paint()..color = const Color(0xFFABCDEF));
+    canvas.drawCircle(
+      const Offset(50, 50),
+      50,
+      Paint()..color = const Color(0xFFABCDEF),
+    );
     final Picture picture = recorder.endRecording();
-    builder.addPicture(const Offset(300, 300), picture);
-
-    final Scene scene = builder.build();
+    sceneBuilder.addPicture(const Offset(300, 300), picture);
+    final Scene scene = sceneBuilder.build();
     window.render(scene);
     scene.dispose();
   }

engine/src/flutter/testing/scenario_app/pubspec.yaml

@@ -8,3 +8,4 @@ dependencies:
    path: ../../../out/host_debug_unopt/gen/dart-pkg/sky_engine
  sky_services:
    path: ../../../out/host_debug_unopt/gen/dart-pkg/sky_services
+ vector_math: ^2.0.8