test: add widget tests for custom themes in theme_test.dart

Author: donnywellson

test/widgets/theme_test.dart

@@ -2,6 +2,9 @@ import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:get/get.dart';
+import 'package:zulip/themes/appbar_theme.dart';
+import 'package:zulip/themes/elevated_button_theme.dart';
 import 'package:zulip/widgets/channel_colors.dart';
 import 'package:zulip/widgets/text.dart';
 import 'package:zulip/widgets/theme.dart';
@@ -133,4 +136,76 @@ void main() {
         .isSameColorSwatchAs(ChannelColorSwatch.dark(baseColor));
     });
   });
+
+  group('ZAppBarTheme Tests', () {
+    testWidgets('Light AppBarThme Test', (tester) async {
+      final designVariables = DesignVariables.light();
+
+      await tester.pumpWidget(GetMaterialApp(
+        home: Scaffold(
+          appBar: AppBar(
+            title: const Text('Test'),
+          ),
+        ),
+      ));
+
+      final context = Get.context;
+
+      final appBarTheme =
+          ZAppBarTheme.lightAppBarTheme(context!, designVariables);
+
+      expect(appBarTheme.backgroundColor, designVariables.bgTopBar);
+      expect(appBarTheme.actionsIconTheme!.color, designVariables.icon);
+      expect(appBarTheme.titleTextStyle!.color, designVariables.title);
+      expect(appBarTheme.titleTextStyle!.fontSize, 20);
+      expect(appBarTheme.titleTextStyle!.fontFamily, kDefaultFontFamily);
+    });
+
+    testWidgets('Dark AppBarThem Test', (tester) async {
+      final designVariables = DesignVariables.dark();
+
+      await tester.pumpWidget(GetMaterialApp(
+        home: Scaffold(
+          appBar: AppBar(
+            title: const Text('Test'),
+          ),
+        ),
+      ));
+
+      final context = Get.context;
+      final appBarTheme =
+          ZAppBarTheme.darkAppBarTheme(context!, designVariables);
+
+      expect(appBarTheme.backgroundColor, designVariables.bgTopBar);
+      expect(appBarTheme.actionsIconTheme!.color, designVariables.icon);
+      expect(appBarTheme.titleTextStyle!.color, designVariables.title);
+      expect(appBarTheme.titleTextStyle!.fontSize, 20);
+      expect(appBarTheme.titleTextStyle!.fontFamily, kDefaultFontFamily);
+    });
+  });
+
+  testWidgets("Zbutton tests", (tester) async{
+    final designVariables = DesignVariables.dark();
+
+      // Use Get.context to access the context directly
+      await tester.pumpWidget(
+        GetMaterialApp(
+          home: Scaffold(
+            body: ElevatedButton(
+              onPressed: () {},
+              child: const Text('Test Button'),
+            ),
+          ),
+        ),
+      );
+
+      // Act
+      final elevatedButtonTheme = ZButtonTheme.darkElevatedButtonTheme(designVariables);
+
+      // Assert
+      final elevatedButtonStyle = elevatedButtonTheme.style!;
+      expect(elevatedButtonStyle.backgroundColor?.resolve({}), designVariables.bgTopBar);
+      expect(elevatedButtonStyle.foregroundColor?.resolve({}), designVariables.title);
+      expect(elevatedButtonStyle.elevation?.resolve({}), 4.0);
+  });
 }