Add automated testing PoC for Guard App login screen

guard_app/__tests__/Login.test.js

@@ -0,0 +1,90 @@
+/* eslint-env jest */
+
+import { render, fireEvent, waitFor } from '@testing-library/react-native';
+import React from 'react';
+import { Alert } from 'react-native';
+
+import LoginScreen from '../src/screen/loginscreen';
+import { ThemeProvider } from '../src/theme/ThemeProvider';
+
+describe('Login Screen', () => {
+  const renderLoginScreen = () => {
+    const navigation = {
+      navigate: jest.fn(),
+      reset: jest.fn(),
+    };
+
+    return {
+      ...render(
+        <ThemeProvider>
+          <LoginScreen navigation={navigation} />
+        </ThemeProvider>,
+      ),
+      navigation,
+    };
+  };
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    jest.spyOn(Alert, 'alert').mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('renders the login form correctly', async () => {
+    const { findByPlaceholderText, findByText } = renderLoginScreen();
+
+    expect(await findByText(/Login with your email and password/i)).toBeTruthy();
+    expect(await findByPlaceholderText('Enter your email')).toBeTruthy();
+    expect(await findByPlaceholderText('Enter your password')).toBeTruthy();
+    expect(await findByText('Login')).toBeTruthy();
+    expect(await findByText('Sign Up')).toBeTruthy();
+  });
+
+  it('shows validation error when fields are empty', async () => {
+    const { findByText } = renderLoginScreen();
+
+    fireEvent.press(await findByText('Login'));
+
+    expect(await findByText('Please enter a valid email address.')).toBeTruthy();
+    expect(Alert.alert).toHaveBeenCalledWith(
+      'Invalid input',
+      'Please enter a valid email address.',
+    );
+  });
+
+  it('shows validation error when password is too short', async () => {
+    const { findByPlaceholderText, findByText } = renderLoginScreen();
+
+    fireEvent.changeText(await findByPlaceholderText('Enter your email'), 'guard@test.com');
+    fireEvent.changeText(await findByPlaceholderText('Enter your password'), '123');
+
+    fireEvent.press(await findByText('Login'));
+
+    expect(await findByText('Password must be at least 6 characters.')).toBeTruthy();
+    expect(Alert.alert).toHaveBeenCalledWith(
+      'Invalid input',
+      'Password must be at least 6 characters.',
+    );
+  });
+
+  it('does not navigate when inputs are invalid', async () => {
+    const { findByText, navigation } = renderLoginScreen();
+
+    fireEvent.press(await findByText('Login'));
+
+    expect(navigation.navigate).not.toHaveBeenCalled();
+  });
+
+  it('navigates to signup screen when Sign Up is pressed', async () => {
+    const { findByText, navigation } = renderLoginScreen();
+
+    fireEvent.press(await findByText('Sign Up'));
+
+    await waitFor(() => {
+      expect(navigation.navigate).toHaveBeenCalledWith('Signup');
+    });
+  });
+});

guard_app/jest.setup.js

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+/* eslint-env jest */
+
+import mockAsyncStorage from '@react-native-async-storage/async-storage/jest/async-storage-mock';
+
+jest.mock('@react-native-async-storage/async-storage', () => mockAsyncStorage);