DiagnosticsTreeStyle.oneLine for CupertinoThemeData (#48084)

packages/flutter/lib/src/cupertino/colors.dart

@@ -1086,7 +1086,7 @@ DiagnosticsProperty<Color> createCupertinoColorProperty(
   Color value, {
     bool showName = true,
     Object defaultValue = kNoDefaultValue,
-    DiagnosticsTreeStyle style = DiagnosticsTreeStyle.shallow,
+    DiagnosticsTreeStyle style = DiagnosticsTreeStyle.singleLine,
     DiagnosticLevel level = DiagnosticLevel.info,
 }) {
   if (value is CupertinoDynamicColor) {

packages/flutter/test/cupertino/theme_test.dart

@@ -190,13 +190,24 @@ void main() {
           'navLargeTitleTextStyle',
           'navActionTextStyle',
           'pickerTextStyle',
-          'dateTimePickerTextStyle'
+          'dateTimePickerTextStyle',
         }
       ),
       isTrue,
     );
   });
 
+  testWidgets('CupertinoTheme.toStringDeep uses single-line style', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/47651.
+    expect(
+      const CupertinoTheme(
+        data: CupertinoThemeData(primaryColor: Color(0x00000000)),
+        child: SizedBox(),
+      ).toStringDeep().trimRight(),
+      isNot(contains('\n')),
+    );
+  });
+
   Brightness currentBrightness;
   void colorMatches(Color componentColor, CupertinoDynamicColor expectedDynamicColor) {
     switch (currentBrightness) {