network-app-mobile/test/features/auth/login_screen_test.dart

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:network_app/features/auth/presentation/login_screen.dart';
import 'package:network_app/shared/services/api_client.dart';
import 'package:mocktail/mocktail.dart';

class MockApiClient extends Mock implements ApiClient {}

void main() {
  late MockApiClient mockApiClient;

  setUp(() {
    mockApiClient = MockApiClient();
  });

  Widget createTestWidget() {
    return ProviderScope(
      overrides: [
        apiClientProvider.overrideWithValue(mockApiClient),
      ],
      child: MaterialApp(
        home: const LoginScreen(),
      ),
    );
  }

  group('LoginScreen Widget Tests', () {
    testWidgets('renders login form', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      expect(find.text('Network App'), findsOneWidget);
      expect(find.text('Sign in to your account'), findsOneWidget);
      expect(find.byType(TextFormField), findsNWidgets(2));
      expect(find.text('Sign In'), findsOneWidget);
    });

    testWidgets('shows email field', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      expect(find.widgetWithText(TextFormField, 'Email'), findsOneWidget);
    });

    testWidgets('shows password field', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      expect(find.widgetWithText(TextFormField, 'Password'), findsOneWidget);
    });

    testWidgets('validates empty email', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      // Enter only password
      await tester.enterText(
        find.widgetWithText(TextFormField, 'Password'),
        'password123',
      );

      // Tap sign in
      await tester.tap(find.text('Sign In'));
      await tester.pumpAndSettle();

      expect(find.text('Please enter your email'), findsOneWidget);
    });

    testWidgets('validates invalid email format', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      await tester.enterText(
        find.widgetWithText(TextFormField, 'Email'),
        'notanemail',
      );
      await tester.enterText(
        find.widgetWithText(TextFormField, 'Password'),
        'password123',
      );

      await tester.tap(find.text('Sign In'));
      await tester.pumpAndSettle();

      expect(find.text('Please enter a valid email'), findsOneWidget);
    });

    testWidgets('validates empty password', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      await tester.enterText(
        find.widgetWithText(TextFormField, 'Email'),
        'test@test.com',
      );

      await tester.tap(find.text('Sign In'));
      await tester.pumpAndSettle();

      expect(find.text('Please enter your password'), findsOneWidget);
    });

    testWidgets('shows loading indicator when signing in', (tester) async {
      final completer = Completer<Map<String, dynamic>>();
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      when(() => mockApiClient.signIn(
        email: any(named: 'email'),
        password: any(named: 'password'),
      )).thenAnswer((_) => completer.future);

      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      await tester.enterText(
        find.widgetWithText(TextFormField, 'Email'),
        'test@test.com',
      );
      await tester.enterText(
        find.widgetWithText(TextFormField, 'Password'),
        'password123',
      );

      await tester.tap(find.text('Sign In'));
      await tester.pump();

      expect(find.byType(CircularProgressIndicator), findsOneWidget);
      
      // Complete to cleanup
      completer.complete({'user': {'id': '1', 'email': 'test@test.com'}});
      await tester.pumpAndSettle();
    });

    testWidgets('shows sign up link', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      
      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      expect(find.text("Don't have an account?"), findsOneWidget);
      expect(find.text('Sign Up'), findsOneWidget);
    });

    testWidgets('shows error message on failed login', (tester) async {
      when(() => mockApiClient.getSession()).thenAnswer((_) async => null);
      when(() => mockApiClient.signIn(
        email: any(named: 'email'),
        password: any(named: 'password'),
      )).thenThrow(Exception('Invalid credentials'));

      await tester.pumpWidget(createTestWidget());
      await tester.pumpAndSettle();

      await tester.enterText(
        find.widgetWithText(TextFormField, 'Email'),
        'test@test.com',
      );
      await tester.enterText(
        find.widgetWithText(TextFormField, 'Password'),
        'wrongpassword',
      );

      await tester.tap(find.text('Sign In'));
      await tester.pumpAndSettle();

      expect(find.text('Invalid email or password'), findsOneWidget);
    });
  });
}