feat: add network error tests

flutter_news_example/test/network_error/network_error_test.dart

@@ -0,0 +1,68 @@
+// ignore_for_file: prefer_const_constructors
+
+import 'package:flutter/material.dart';
+import 'package:flutter_news_example/network_error/network_error.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:go_router/go_router.dart';
+import 'package:mocktail/mocktail.dart';
+
+import '../helpers/helpers.dart';
+
+class MockGoRouter extends Mock implements GoRouter {}
+
+void main() {
+  const tapMeText = 'Tap Me';
+  late GoRouter goRouter;
+
+  setUpAll(() {
+    goRouter = MockGoRouter();
+    when(() => goRouter.goNamed(NetworkErrorPage.routePath)).thenAnswer((_) {});
+  });
+
+  group('NetworkError', () {
+    testWidgets('renders correctly', (tester) async {
+      await tester.pumpApp(NetworkError());
+
+      expect(find.byType(NetworkError), findsOneWidget);
+    });
+
+    testWidgets('navigates to network error page routePath', (tester) async {
+      await tester.pumpApp(
+        InheritedGoRouter(
+          goRouter: goRouter,
+          child: Scaffold(
+            body: Builder(
+              builder: (context) {
+                return ElevatedButton(
+                  onPressed: () {
+                    context.goNamed(NetworkErrorPage.routePath);
+                  },
+                  child: const Text(tapMeText),
+                );
+              },
+            ),
+          ),
+        ),
+      );
+
+      await tester.tap(find.text(tapMeText));
+
+      verify(() => goRouter.goNamed(NetworkErrorPage.routePath)).called(1);
+    });
+  });
+
+  testWidgets('calls onRetry function when button pressed', (tester) async {
+    var retryPressed = false;
+    await tester.pumpApp(
+      NetworkError(
+        onRetry: () {
+          retryPressed = true;
+        },
+      ),
+    );
+
+    await tester.tap(find.byType(ElevatedButton));
+
+    expect(retryPressed, isTrue);
+  });
+}