settings test [nfc]: Pull out checkRadioButtonAppearsChecked helper

Author: chrisbobbe

test/widgets/settings_test.dart

@@ -26,11 +26,25 @@ void main() {
     await tester.pump();
   }
 
-  group('ThemeSetting', () {
-    Finder findRadioListTileWithTitle(String title) => find.ancestor(
-      of: find.text(title),
-      matching: find.byType(RadioListTile<ThemeSetting?>));
+  Finder findRadioListTileWithTitle<T>(String title) => find.ancestor(
+    of: find.text(title),
+    matching: find.byType(RadioListTile<T>));
+
+  void checkRadioButtonAppearsChecked<T>(WidgetTester tester, String title, bool expectedIsChecked) {
+    final element = tester.element(findRadioListTileWithTitle<T>(title));
+      final checkedColor = Theme.of(element).colorScheme.primary;
+      // `paints` isn't a [Matcher] so we wrap it with `equals`;
+      // awkward but it works
+      final paintsAsCheckedMatcher = equals(paints..circle(color: checkedColor));
+      check(because: '$title should be ${expectedIsChecked ? 'checked' : 'unchecked'}',
+        element.renderObject,
+      ).legacyMatcher(
+        expectedIsChecked
+          ? paintsAsCheckedMatcher
+          : isNot(paintsAsCheckedMatcher));
+  }
 
+  group('ThemeSetting', () {
     void checkThemeSetting(WidgetTester tester, {
       required ThemeSetting? expectedThemeSetting,
     }) {
@@ -40,18 +54,7 @@ void main() {
         ThemeSetting.dark => 'Dark',
       };
       for (final title in ['System', 'Light', 'Dark']) {
-        final expectedIsChecked = title == expectedCheckedTitle;
-        final element = tester.element(findRadioListTileWithTitle(title));
-        final checkedColor = Theme.of(element).colorScheme.primary;
-        // `paints` isn't a [Matcher] so we wrap it with `equals`;
-        // awkward but it works
-        final paintsAsCheckedMatcher = equals(paints..circle(color: checkedColor));
-        check(because: '$title should be ${expectedIsChecked ? 'checked' : 'unchecked'}',
-          element.renderObject,
-        ).legacyMatcher(
-          expectedIsChecked
-            ? paintsAsCheckedMatcher
-            : isNot(paintsAsCheckedMatcher));
+        checkRadioButtonAppearsChecked<ThemeSetting?>(tester, title, title == expectedCheckedTitle);
       }
       check(testBinding.globalStore)
         .settings.themeSetting.equals(expectedThemeSetting);
@@ -66,13 +69,13 @@ void main() {
       check(Theme.of(element)).brightness.equals(Brightness.light);
       checkThemeSetting(tester, expectedThemeSetting: ThemeSetting.light);
 
-      await tester.tap(findRadioListTileWithTitle('Dark'));
+      await tester.tap(findRadioListTileWithTitle<ThemeSetting?>('Dark'));
       await tester.pump();
       await tester.pump(Duration(milliseconds: 250)); // wait for transition
       check(Theme.of(element)).brightness.equals(Brightness.dark);
       checkThemeSetting(tester, expectedThemeSetting: ThemeSetting.dark);
 
-      await tester.tap(findRadioListTileWithTitle('System'));
+      await tester.tap(findRadioListTileWithTitle<ThemeSetting?>('System'));
       await tester.pump();
       await tester.pump(Duration(milliseconds: 250)); // wait for transition
       check(Theme.of(element)).brightness.equals(Brightness.light);