Added golden test to make sure that spawn engines work.

Author: gaaclarke

testing/scenario_app/ios/Scenarios/Scenarios.xcodeproj/project.pbxproj

@@ -23,6 +23,8 @@
 		0DB7820022EA2C9D00E9B371 /* App.framework in CopyFiles */ = {isa = PBXBuildFile; fileRef = 246B4E4122E3B5F700073EBF /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		0DB7820122EA2CA500E9B371 /* App.framework in CopyFiles */ = {isa = PBXBuildFile; fileRef = 246B4E4122E3B5F700073EBF /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		0DB7820222EA493B00E9B371 /* FlutterViewControllerTest.m in Sources */ = {isa = PBXBuildFile; fileRef = 0DB781FC22EA2C0300E9B371 /* FlutterViewControllerTest.m */; };
+		0DDEBC89258830B40065D0E8 /* SpawnEngineTest.m in Sources */ = {isa = PBXBuildFile; fileRef = 0DDEBC88258830B40065D0E8 /* SpawnEngineTest.m */; };
+		0DDEBC8B258839760065D0E8 /* golden_spawn_engine_works_iPhone 8_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 0DDEBC8A258839760065D0E8 /* golden_spawn_engine_works_iPhone 8_simulator.png */; };
 		242F37A222E636DE001E83D4 /* Flutter.xcframework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 246B4E4522E3B61000073EBF /* Flutter.xcframework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		242F37A322E636DE001E83D4 /* App.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 246B4E4122E3B5F700073EBF /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		244EA6D0230DBE8900B2D26E /* golden_platform_view_D21AP.png in Resources */ = {isa = PBXBuildFile; fileRef = 244EA6CF230DBE8900B2D26E /* golden_platform_view_D21AP.png */; };
@@ -124,6 +126,9 @@
 		0D8470A2240F0B1F0030B565 /* StatusBarTest.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = StatusBarTest.h; sourceTree = "<group>"; };
 		0D8470A3240F0B1F0030B565 /* StatusBarTest.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = StatusBarTest.m; sourceTree = "<group>"; };
 		0DB781FC22EA2C0300E9B371 /* FlutterViewControllerTest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = FlutterViewControllerTest.m; sourceTree = "<group>"; };
+		0DDEBC87258830B40065D0E8 /* SpawnEngineTest.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SpawnEngineTest.h; sourceTree = "<group>"; };
+		0DDEBC88258830B40065D0E8 /* SpawnEngineTest.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SpawnEngineTest.m; sourceTree = "<group>"; };
+		0DDEBC8A258839760065D0E8 /* golden_spawn_engine_works_iPhone 8_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_spawn_engine_works_iPhone 8_simulator.png"; sourceTree = "<group>"; };
 		244EA6CF230DBE8900B2D26E /* golden_platform_view_D21AP.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = golden_platform_view_D21AP.png; sourceTree = "<group>"; };
 		246A6610252E693A00EAB0F3 /* RenderingSelectionTest.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RenderingSelectionTest.m; sourceTree = "<group>"; };
 		246B4E4122E3B5F700073EBF /* App.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = App.framework; sourceTree = "<group>"; };
@@ -252,6 +257,7 @@
 		248D76ED22E388380012F0C1 /* ScenariosUITests */ = {
 			isa = PBXGroup;
 			children = (
+				0DDEBC8A258839760065D0E8 /* golden_spawn_engine_works_iPhone 8_simulator.png */,
 				4F06F1B124731F66000AF246 /* LocalizationInitializationTest.m */,
 				6402EBD024147BDA00987DCB /* UnobstructedPlatformViewTests.m */,
 				0AC83145256E534E00DAE6BE /* golden_bogus_font_text_iPhone 8_simulator.png */,
@@ -284,6 +290,8 @@
 				0A42BFB32447E179007E212E /* TextSemanticsFocusTest.m */,
 				0A42BFB52447E19F007E212E /* TextSemanticsFocusTest.h */,
 				246A6610252E693A00EAB0F3 /* RenderingSelectionTest.m */,
+				0DDEBC87258830B40065D0E8 /* SpawnEngineTest.h */,
+				0DDEBC88258830B40065D0E8 /* SpawnEngineTest.m */,
 			);
 			path = ScenariosUITests;
 			sourceTree = "<group>";
@@ -433,6 +441,7 @@
 				59A97FDA236B984300B4C066 /* golden_platform_view_multiple_background_foreground_iPhone SE_simulator.png in Resources */,
 				3DEF491923C3BE6500184216 /* golden_platform_view_rotate_iPhone 8_simulator.png in Resources */,
 				24D47D1B230C79840069DD5E /* golden_platform_view_D211AP.png in Resources */,
+				0DDEBC8B258839760065D0E8 /* golden_spawn_engine_works_iPhone 8_simulator.png in Resources */,
 				244EA6D0230DBE8900B2D26E /* golden_platform_view_D21AP.png in Resources */,
 				3DEF491A23C3BE6500184216 /* golden_platform_view_transform_iPhone 8_simulator.png in Resources */,
 			);
@@ -480,6 +489,7 @@
 				246A6611252E693A00EAB0F3 /* RenderingSelectionTest.m in Sources */,
 				4F06F1B32473296E000AF246 /* LocalizationInitializationTest.m in Sources */,
 				0A42BFB42447E179007E212E /* TextSemanticsFocusTest.m in Sources */,
+				0DDEBC89258830B40065D0E8 /* SpawnEngineTest.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

testing/scenario_app/ios/Scenarios/Scenarios.xcodeproj/xcshareddata/xcschemes/Scenarios.xcscheme

@@ -28,6 +28,18 @@
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
       systemAttachmentLifetime = "keepNever">
+      <AdditionalOptions>
+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
+      </AdditionalOptions>
       <Testables>
          <TestableReference
             skipped = "NO"

testing/scenario_app/ios/Scenarios/Scenarios/AppDelegate.m

@@ -54,7 +54,8 @@ - (BOOL)application:(UIApplication*)application
     @"--text-semantics-focus" : @"text_semantics_focus",
     @"--animated-color-square" : @"animated_color_square",
     @"--platform-view-with-continuous-texture" : @"platform_view_with_continuous_texture",
-    @"--bogus-font-text" : @"bogus_font_text"
+    @"--bogus-font-text" : @"bogus_font_text",
+    @"--spawn-engine-works" : @"spawn_engine_works",
   };
   __block NSString* flutterViewControllerTestName = nil;
   [launchArgsMap
@@ -80,6 +81,25 @@ - (BOOL)application:(UIApplication*)application
   return [super application:application didFinishLaunchingWithOptions:launchOptions];
 }
 
+// TODO(https://github.com/flutter/flutter/issues/72019) Sharing threads doesn't work correctly yet
+// so we need to keep the Spawning engine alive.  Once this issue is fixed we can remove s_spawner.
+static FlutterEngine* s_spawner;
+
+- (FlutterEngine*)engineForTest:(NSString*)scenarioIdentifier {
+  if ([scenarioIdentifier isEqualToString:@"spawn_engine_works"]) {
+    if (s_spawner == nil) {
+      s_spawner = [[FlutterEngine alloc] initWithName:@"FlutterControllerTest" project:nil];
+      [s_spawner run];
+    }
+    return [s_spawner spawnWithEntrypoint:nil libraryURI:nil];
+  } else {
+    FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"FlutterControllerTest"
+                                                        project:nil];
+    [engine run];
+    return engine;
+  }
+}
+
 - (FlutterViewController*)flutterViewControllerForTest:(NSString*)scenarioIdentifier
                                             withEngine:(FlutterEngine*)engine {
   if ([scenarioIdentifier isEqualToString:@"tap_status_bar"]) {
@@ -90,9 +110,7 @@ - (FlutterViewController*)flutterViewControllerForTest:(NSString*)scenarioIdenti
 }
 
 - (void)setupFlutterViewControllerTest:(NSString*)scenarioIdentifier {
-  FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"FlutterControllerTest" project:nil];
-  [engine run];
-
+  FlutterEngine* engine = [self engineForTest:scenarioIdentifier];
   FlutterViewController* flutterViewController =
       [self flutterViewControllerForTest:scenarioIdentifier withEngine:engine];
 

testing/scenario_app/ios/Scenarios/Scenarios/FlutterEngine+ScenariosTest.h

@@ -8,5 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 @interface FlutterEngine (ScenariosTest)
 - (instancetype)initWithScenario:(NSString*)scenario
                   withCompletion:(nullable void (^)(void))engineRunCompletion;
+- (FlutterEngine*)spawnWithEntrypoint:(nullable NSString*)entrypoint
+                           libraryURI:(nullable NSString*)libraryURI;
 @end
 NS_ASSUME_NONNULL_END

testing/scenario_app/ios/Scenarios/ScenariosUITests/SpawnEngineTest.h

@@ -0,0 +1,13 @@
+// Copyright 2020 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>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface SpawnEngineTest : XCTestCase
+@property(nonatomic, strong) XCUIApplication* application;
+@end
+
+NS_ASSUME_NONNULL_END

testing/scenario_app/ios/Scenarios/ScenariosUITests/SpawnEngineTest.m

@@ -0,0 +1,38 @@
+// Copyright 2020 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 "SpawnEngineTest.h"
+#import "GoldenImage.h"
+
+@implementation SpawnEngineTest
+
+- (void)setUp {
+  [super setUp];
+  self.continueAfterFailure = NO;
+
+  self.application = [[XCUIApplication alloc] init];
+  self.application.launchArguments = @[ @"--spawn-engine-works", @"--enable-software-rendering" ];
+  [self.application launch];
+}
+
+- (void)testSpawnEngineWorks {
+  NSString* prefix = @"golden_spawn_engine_works_";
+  GoldenImage* golden = [[GoldenImage alloc] initWithGoldenNamePrefix:prefix];
+  if (!golden.image) {
+    XCTFail(@"unable to find golden image for: %@", prefix);
+  }
+  XCUIScreenshot* screenshot = [[XCUIScreen mainScreen] screenshot];
+  if (![golden compareGoldenToImage:screenshot.image]) {
+    XCTAttachment* screenshotAttachment = [XCTAttachment attachmentWithImage:screenshot.image];
+    screenshotAttachment.name = [golden.goldenName stringByAppendingString:@"_actual"];
+    screenshotAttachment.lifetime = XCTAttachmentLifetimeKeepAlways;
+    [self addAttachment:screenshotAttachment];
+
+    XCTFail(@"Goldens do not match. Follow the steps in the "
+            @"README to update golden named %@ if needed.",
+            golden.goldenName);
+  }
+}
+
+@end

testing/scenario_app/ios/Scenarios/ScenariosUITests/golden_spawn_engine_works_iPhone 8_simulator.png

@@ -46,6 +46,7 @@ Map<String, ScenarioFactory> _scenarios = <String, ScenarioFactory>{
   'initial_route_reply': () => InitialRouteReply(PlatformDispatcher.instance),
   'platform_view_with_continuous_texture': () => PlatformViewWithContinuousTexture(PlatformDispatcher.instance, 'Platform View', id: _viewId++),
   'bogus_font_text': () => BogusFontText(PlatformDispatcher.instance),
+  'spawn_engine_works' : () => BogusFontText(PlatformDispatcher.instance),
 };
 
 Map<String, dynamic> _currentScenarioParams = <String, dynamic>{};