Added negative test and blur test to the wide gamut tests. (#120914)

* Added negative test and blur test to the wide gamut tests.

* switched back to dstOver

* fixed blur test

* analysis warnings

* analyzer

dev/integration_tests/wide_gamut_test/integration_test/app_test.dart

@@ -23,7 +23,10 @@ bool _isAlmost(double x, double y, double epsilon) {
   return (x - y).abs() < epsilon;
 }
 
-bool _findDeepRedBGRA10(Uint8List bytes, int width, int height) {
+List<double> _deepRed = <double>[1.0931, -0.2268, -0.1501];
+
+bool _findBGRA10Color(
+    Uint8List bytes, int width, int height, List<double> color) {
   final ByteData byteData = ByteData.sublistView(bytes);
   expect(bytes.lengthInBytes, width * height * 8);
   expect(bytes.lengthInBytes, byteData.lengthInBytes);
@@ -33,16 +36,17 @@ bool _findDeepRedBGRA10(Uint8List bytes, int width, int height) {
     final double blue = _decodeBGR10((pixel >> 6) & 0x3ff);
     final double green = _decodeBGR10((pixel >> 22) & 0x3ff);
     final double red = _decodeBGR10((pixel >> 38) & 0x3ff);
-    if (_isAlmost(red, 1.0931, 0.01) &&
-        _isAlmost(green, -0.2268, 0.01) &&
-        _isAlmost(blue, -0.1501, 0.01)) {
+    if (_isAlmost(red, color[0], 0.01) &&
+        _isAlmost(green, color[1], 0.01) &&
+        _isAlmost(blue, color[2], 0.01)) {
       foundDeepRed = true;
     }
   }
   return foundDeepRed;
 }
 
-bool _findDeepRedBGR10(Uint8List bytes, int width, int height) {
+bool _findBGR10Color(
+    Uint8List bytes, int width, int height, List<double> color) {
   final ByteData byteData = ByteData.sublistView(bytes);
   expect(bytes.lengthInBytes, width * height * 4);
   expect(bytes.lengthInBytes, byteData.lengthInBytes);
@@ -52,25 +56,25 @@ bool _findDeepRedBGR10(Uint8List bytes, int width, int height) {
     final double blue = _decodeBGR10(pixel & 0x3ff);
     final double green = _decodeBGR10((pixel >> 10) & 0x3ff);
     final double red = _decodeBGR10((pixel >> 20) & 0x3ff);
-    if (_isAlmost(red, 1.0931, 0.01) &&
-        _isAlmost(green, -0.2268, 0.01) &&
-        _isAlmost(blue, -0.1501, 0.01)) {
+    if (_isAlmost(red, color[0], 0.01) &&
+        _isAlmost(green, color[1], 0.01) &&
+        _isAlmost(blue, color[2], 0.01)) {
       foundDeepRed = true;
     }
   }
   return foundDeepRed;
 }
 
-bool _findDeepRed(List<Object?> result) {
+bool _findColor(List<Object?> result, List<double> color) {
   expect(result, isNotNull);
   expect(result.length, 4);
   final int width = (result[0] as int?)!;
   final int height = (result[1] as int?)!;
   final String format = (result[2] as String?)!;
   if (format == 'MTLPixelFormatBGR10_XR') {
-    return _findDeepRedBGR10((result[3] as Uint8List?)!, width, height);
+    return _findBGR10Color((result[3] as Uint8List?)!, width, height, color);
   } else if (format == 'MTLPixelFormatBGRA10_XR') {
-    return _findDeepRedBGRA10((result[3] as Uint8List?)!, width, height);
+    return _findBGRA10Color((result[3] as Uint8List?)!, width, height, color);
   } else {
     fail('Unsupported pixel format: $format');
   }
@@ -87,7 +91,7 @@ void main() {
       const MethodChannel channel = MethodChannel('flutter/screenshot');
       final List<Object?> result =
           await channel.invokeMethod('test') as List<Object?>;
-      expect(_findDeepRed(result), isTrue);
+      expect(_findColor(result, _deepRed), isTrue);
     });
     testWidgets('look for display p3 deepest red', (WidgetTester tester) async {
       app.run(app.Setup.canvasSaveLayer);
@@ -96,7 +100,27 @@ void main() {
       const MethodChannel channel = MethodChannel('flutter/screenshot');
       final List<Object?> result =
           await channel.invokeMethod('test') as List<Object?>;
-      expect(_findDeepRed(result), isTrue);
+      expect(_findColor(result, _deepRed), isTrue);
+    });
+    testWidgets('no p3 deepest red without image', (WidgetTester tester) async {
+      app.run(app.Setup.none);
+      await tester.pumpAndSettle(const Duration(seconds: 2));
+
+      const MethodChannel channel = MethodChannel('flutter/screenshot');
+      final List<Object?> result =
+          await channel.invokeMethod('test') as List<Object?>;
+      expect(_findColor(result, _deepRed), isFalse);
+      expect(_findColor(result, <double>[0.0, 1.0, 0.0]), isFalse);
+    });
+    testWidgets('p3 deepest red with blur', (WidgetTester tester) async {
+      app.run(app.Setup.blur);
+      await tester.pumpAndSettle(const Duration(seconds: 2));
+
+      const MethodChannel channel = MethodChannel('flutter/screenshot');
+      final List<Object?> result =
+          await channel.invokeMethod('test') as List<Object?>;
+      expect(_findColor(result, _deepRed), isTrue);
+      expect(_findColor(result, <double>[0.0, 1.0, 0.0]), isTrue);
     });
   });
 }