[macOS] Replace pasteboard mock with fake

shell/platform/darwin/macos/framework/Source/FlutterEngine.mm

@@ -275,6 +275,24 @@ - (void)requestApplicationTermination:(id)sender
 
 #pragma mark -
 
+@implementation FlutterPasteboard
+
+- (NSInteger)clearContents {
+  return [[NSPasteboard generalPasteboard] clearContents];
+}
+
+- (NSString*)stringForType:(NSPasteboardType)dataType {
+  return [[NSPasteboard generalPasteboard] stringForType:dataType];
+}
+
+- (BOOL)setString:(nonnull NSString*)string forType:(nonnull NSPasteboardType)dataType {
+  return [[NSPasteboard generalPasteboard] setString:string forType:dataType];
+}
+
+@end
+
+#pragma mark -
+
 /**
  * `FlutterPluginRegistrar` implementation handling a single plugin.
  */
@@ -452,6 +470,7 @@ - (instancetype)initWithName:(NSString*)labelPrefix
       allowHeadlessExecution:(BOOL)allowHeadlessExecution {
   self = [super init];
   NSAssert(self, @"Super init cannot be nil");
+  _pasteboard = [[FlutterPasteboard alloc] init];
   _active = NO;
   _visible = NO;
   _project = project ?: [[FlutterDartProject alloc] init];
@@ -1186,31 +1205,25 @@ - (void)playSystemSound:(NSString*)soundType {
 }
 
 - (NSDictionary*)getClipboardData:(NSString*)format {
-  NSPasteboard* pasteboard = self.pasteboard;
   if ([format isEqualToString:@(kTextPlainFormat)]) {
-    NSString* stringInPasteboard = [pasteboard stringForType:NSPasteboardTypeString];
+    NSString* stringInPasteboard = [self.pasteboard stringForType:NSPasteboardTypeString];
     return stringInPasteboard == nil ? nil : @{@"text" : stringInPasteboard};
   }
   return nil;
 }
 
 - (void)setClipboardData:(NSDictionary*)data {
-  NSPasteboard* pasteboard = self.pasteboard;
   NSString* text = data[@"text"];
-  [pasteboard clearContents];
+  [self.pasteboard clearContents];
   if (text && ![text isEqual:[NSNull null]]) {
-    [pasteboard setString:text forType:NSPasteboardTypeString];
+    [self.pasteboard setString:text forType:NSPasteboardTypeString];
   }
 }
 
 - (BOOL)clipboardHasStrings {
   return [self.pasteboard stringForType:NSPasteboardTypeString].length > 0;
 }
 
-- (NSPasteboard*)pasteboard {
-  return [NSPasteboard generalPasteboard];
-}
-
 - (std::vector<std::string>)switches {
   return flutter::GetSwitchesFromEnvironment();
 }

shell/platform/darwin/macos/framework/Source/FlutterEngineTestUtils.mm

@@ -4,11 +4,40 @@
 // found in the LICENSE file.
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngineTestUtils.h"
+
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterDartProject_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h"
 
 #include "flutter/testing/testing.h"
 
+/**
+ * Fake pasteboard implementation to allow tests to work in environments without a real
+ * pasteboard.
+ */
+@interface FakePasteboard : FlutterPasteboard
+@end
+
+@implementation FakePasteboard {
+  NSString* _result;
+}
+
+- (NSInteger)clearContents {
+  size_t changeCount = (_result != nil) ? 1 : 0;
+  _result = nil;
+  return changeCount;
+}
+
+- (NSString*)stringForType:(NSPasteboardType)dataType {
+  return _result;
+}
+
+- (BOOL)setString:(NSString*)string forType:(NSPasteboardType)dataType {
+  _result = string;
+  return YES;
+}
+
+@end
+
 namespace flutter::testing {
 
 FlutterEngineTest::FlutterEngineTest() = default;
@@ -45,26 +74,19 @@
 }
 
 id CreateMockFlutterEngine(NSString* pasteboardString) {
-  {
-    NSString* fixtures = @(testing::GetFixturesPath());
-    FlutterDartProject* project = [[FlutterDartProject alloc]
-        initWithAssetsPath:fixtures
-               ICUDataPath:[fixtures stringByAppendingString:@"/icudtl.dat"]];
-    FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"test"
-                                                        project:project
-                                         allowHeadlessExecution:true];
-
-    // Mock pasteboard so that this test will work in environments without a
-    // real pasteboard.
-    id pasteboardMock = OCMClassMock([NSPasteboard class]);
-    OCMExpect([pasteboardMock stringForType:[OCMArg any]]).andDo(^(NSInvocation* invocation) {
-      NSString* returnValue = pasteboardString.length > 0 ? pasteboardString : nil;
-      [invocation setReturnValue:&returnValue];
-    });
-    id engineMock = OCMPartialMock(engine);
-    OCMStub([engineMock pasteboard]).andReturn(pasteboardMock);
-    return engineMock;
-  }
+  NSString* fixtures = @(testing::GetFixturesPath());
+  FlutterDartProject* project = [[FlutterDartProject alloc]
+      initWithAssetsPath:fixtures
+             ICUDataPath:[fixtures stringByAppendingString:@"/icudtl.dat"]];
+  FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"test"
+                                                      project:project
+                                       allowHeadlessExecution:true];
+
+  FakePasteboard* pasteboardMock = [[FakePasteboard alloc] init];
+  [pasteboardMock setString:pasteboardString forType:NSPasteboardTypeString];
+  engine.pasteboard = pasteboardMock;
+  id engineMock = OCMPartialMock(engine);
+  return engineMock;
 }
 
 MockFlutterEngineTest::MockFlutterEngineTest() = default;

shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h

@@ -66,6 +66,15 @@ typedef NS_ENUM(NSInteger, FlutterAppExitResponse) {
                                result:(nullable FlutterResult)result;
 @end
 
+/**
+ * An NSPasteboard wrapper object to allow for substitution of a fake in unit tests.
+ */
+@interface FlutterPasteboard : NSObject
+- (NSInteger)clearContents;
+- (NSString*)stringForType:(NSPasteboardType)dataType;
+- (BOOL)setString:(NSString*)string forType:(NSPasteboardType)dataType;
+@end
+
 @interface FlutterEngine ()
 
 /**
@@ -98,7 +107,7 @@ typedef NS_ENUM(NSInteger, FlutterAppExitResponse) {
 /**
  * This just returns the NSPasteboard so that it can be mocked in the tests.
  */
-@property(nonatomic, readonly, nonnull) NSPasteboard* pasteboard;
+@property(nonatomic, nonnull) FlutterPasteboard* pasteboard;
 
 /**
  * The command line arguments array for the engine.