Add tests for agent email sign-in block in BaseLoginForm

Adds two tests covering the new isAgentEmail guard in
validateAndSubmitForm: one verifies the error message appears and
beginSignIn is not called for agent emails, the other verifies
normal emails proceed to sign-in as expected.

Co-authored-by: Nicolás Bonet <NicolasBonet@users.noreply.github.com>

Author: MelvinBot

tests/ui/BaseLoginFormTest.tsx

@@ -0,0 +1,120 @@
+import type * as ReactNavigationNative from '@react-navigation/native';
+import {fireEvent, render, screen, waitFor} from '@testing-library/react-native';
+import React from 'react';
+import Onyx from 'react-native-onyx';
+import {LoginProvider} from '@pages/signin/SignInLoginContext';
+import {beginSignIn} from '@userActions/Session';
+import ONYXKEYS from '@src/ONYXKEYS';
+import waitForBatchedUpdates from '../utils/waitForBatchedUpdates';
+
+jest.mock('@react-navigation/native', () => {
+    const actualNav = jest.requireActual<typeof ReactNavigationNative>('@react-navigation/native');
+    return {
+        ...actualNav,
+        useIsFocused: () => true,
+    };
+});
+
+const AGENT_ERROR = "Agent accounts can't be signed into directly. To use an agent, sign in with your own account and access it via Copilot.";
+const INVALID_EMAIL_ERROR = 'The email entered is invalid. Please fix the format and try again.';
+
+jest.mock('@hooks/useLocalize', () =>
+    jest.fn(() => ({
+        translate: jest.fn((key: string) => {
+            switch (key) {
+                case 'loginForm.error.agentSignInBlocked':
+                    return AGENT_ERROR;
+                case 'loginForm.error.invalidFormatEmailLogin':
+                    return INVALID_EMAIL_ERROR;
+                case 'loginForm.phoneOrEmail':
+                    return 'Phone or email';
+                case 'loginForm.loginForm':
+                    return 'Login form';
+                case 'common.continue':
+                    return 'Continue';
+                case 'common.signInWith':
+                    return 'Sign in with';
+                case 'common.pleaseEnterEmailOrPhoneNumber':
+                    return 'Please enter an email or phone number';
+                default:
+                    return key;
+            }
+        }),
+        numberFormat: jest.fn(),
+    })),
+);
+
+jest.mock('@hooks/useResponsiveLayout', () =>
+    jest.fn(() => ({
+        shouldUseNarrowLayout: false,
+        isInNarrowPaneModal: false,
+    })),
+);
+
+jest.mock('@userActions/Session', () => ({
+    beginSignIn: jest.fn(),
+    clearAccountMessages: jest.fn(),
+    clearSignInData: jest.fn(),
+}));
+
+jest.mock('@userActions/CloseAccount', () => ({
+    setDefaultData: jest.fn(),
+}));
+
+// Use require to get the default export after all jest.mock calls are hoisted
+// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access
+const BaseLoginForm = require('@pages/signin/LoginForm/BaseLoginForm').default;
+
+const mockBeginSignIn = beginSignIn as jest.MockedFunction<typeof beginSignIn>;
+
+function renderForm() {
+    return render(
+        <LoginProvider>
+            <BaseLoginForm isVisible />
+        </LoginProvider>,
+    );
+}
+
+describe('BaseLoginForm', () => {
+    beforeAll(() => {
+        Onyx.init({keys: ONYXKEYS});
+    });
+
+    beforeEach(async () => {
+        jest.clearAllMocks();
+        await Onyx.set(ONYXKEYS.ACCOUNT, {
+            isLoading: false,
+            errors: null,
+        });
+        await waitForBatchedUpdates();
+    });
+
+    it('shows agent sign-in blocked error when an agent email is entered', async () => {
+        renderForm();
+
+        const input = screen.getByTestId('username');
+        fireEvent.changeText(input, 'agent_123@expensify.ai');
+
+        const continueButton = screen.getByText('Continue');
+        fireEvent.press(continueButton);
+
+        await waitFor(() => {
+            expect(screen.getByText(AGENT_ERROR)).toBeTruthy();
+        });
+        expect(mockBeginSignIn).not.toHaveBeenCalled();
+    });
+
+    it('proceeds with sign-in for a normal email', async () => {
+        renderForm();
+
+        const input = screen.getByTestId('username');
+        fireEvent.changeText(input, 'user@expensify.com');
+
+        const continueButton = screen.getByText('Continue');
+        fireEvent.press(continueButton);
+
+        await waitFor(() => {
+            expect(mockBeginSignIn).toHaveBeenCalledWith('user@expensify.com');
+        });
+    });
+});