QUICKFIX Background Color Widget

*FIX background color incorrectly used as a widget.
*Add tests to validate fix.

Author: rayliverified

example

@@ -483,10 +483,8 @@ class _ResponsiveWrapperState extends State<ResponsiveWrapper>
   Widget build(BuildContext context) {
     return (screenWidth ==
             0) // Initialization check. Window measurements not available until postFrameCallback.
-        ? (widget.backgroundColor ??
-            Container(
-                color: Color(
-                    0xFFFFFFFF))) // First frame empty background color or default white.
+        ? buildBackgroundColorWidget(widget
+            .backgroundColor) // First frame empty background color or default white.
         : InheritedResponsiveWrapper(
             data: ResponsiveWrapperData.fromResponsiveWrapper(this),
             child: Stack(
@@ -541,6 +539,13 @@ class _ResponsiveWrapperState extends State<ResponsiveWrapper>
         viewPadding: scaledViewPadding,
         padding: scaledPadding);
   }
+
+  /// Builds a container with [color].
+  /// Defaults to a white background.
+  Widget buildBackgroundColorWidget(Color color) {
+    if (color == null) return Container(color: Color(0xFFFFFFFF));
+    return Container(color: color);
+  }
 }
 
 // Device Type Constants.

lib/responsive_wrapper.dart

@@ -269,6 +269,39 @@ void main() {
       // Scale factor is 4.
       expect(state.screenWidth, 200);
     });
+
+    testWidgets('Background Color', (WidgetTester tester) async {
+      // 0 width to simulate screen loading.
+      setScreenSize(tester, Size(0, 1200));
+      Widget widget = MaterialApp(
+        builder: (context, widget) =>
+            ResponsiveWrapper.builder(widget, backgroundColor: Colors.amber),
+        home: Container(),
+      );
+      // Pump once to trigger one frame build.
+      await tester.pumpWidget(widget);
+      // Expect only a container with color.
+      WidgetPredicate widgetPredicate = (Widget widget) =>
+          widget is Container && widget.color == Colors.amber;
+      // Confirm defaults.
+      expect(find.byWidgetPredicate(widgetPredicate), findsOneWidget);
+    });
+
+    testWidgets('Background Color Null', (WidgetTester tester) async {
+      // 0 width to simulate screen loading.
+      setScreenSize(tester, Size(0, 1200));
+      Widget widget = MaterialApp(
+        builder: (context, widget) => ResponsiveWrapper.builder(widget),
+        home: Container(),
+      );
+      // Pump once to trigger one frame build.
+      await tester.pumpWidget(widget);
+      // Expect only a container with default white color.
+      WidgetPredicate widgetPredicate = (Widget widget) =>
+          widget is Container && widget.color == Colors.white;
+      // Confirm defaults.
+      expect(find.byWidgetPredicate(widgetPredicate), findsOneWidget);
+    });
   });
 
   group('ResponsiveBreakpoint', () {