Add series fields to audiobooks and update related logic

Introduces 'series' and 'seriesPart' fields to the Audiobook model and database schema. Updates API routes, file organization, and path template utilities to support series metadata. Enhances chapter merging logic, improves notification backend testing, and expands test coverage for admin and API routes.

tests/components/ui/ChangePasswordModal.test.tsx

@@ -0,0 +1,121 @@
+/**
+ * Component: Change Password Modal Tests
+ * Documentation: documentation/frontend/components.md
+ */
+
+// @vitest-environment jsdom
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { act, fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { ChangePasswordModal } from '@/components/ui/ChangePasswordModal';
+
+describe('ChangePasswordModal', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.useRealTimers();
+    localStorage.clear();
+  });
+
+  it('shows validation errors when required fields are missing', () => {
+    render(<ChangePasswordModal isOpen onClose={vi.fn()} />);
+
+    fireEvent.click(screen.getByRole('button', { name: 'Change Password' }));
+
+    expect(screen.getByText('Current password is required')).toBeInTheDocument();
+    expect(screen.getByText('New password is required')).toBeInTheDocument();
+    expect(screen.getByText('Please confirm your new password')).toBeInTheDocument();
+  });
+
+  it('rejects submission when access token is missing', async () => {
+    const fetchMock = vi.fn();
+    vi.stubGlobal('fetch', fetchMock);
+
+    render(<ChangePasswordModal isOpen onClose={vi.fn()} />);
+
+    fireEvent.change(screen.getByLabelText('Current Password'), {
+      target: { value: 'old-password' },
+    });
+    fireEvent.change(screen.getByLabelText('New Password'), {
+      target: { value: 'new-password' },
+    });
+    fireEvent.change(screen.getByLabelText('Confirm New Password'), {
+      target: { value: 'new-password' },
+    });
+
+    fireEvent.click(screen.getByRole('button', { name: 'Change Password' }));
+
+    await waitFor(() => {
+      expect(screen.getByText('Not authenticated')).toBeInTheDocument();
+    });
+
+    expect(fetchMock).not.toHaveBeenCalled();
+  });
+
+  it('submits successfully and auto-closes after showing success', async () => {
+    vi.useFakeTimers();
+    const onClose = vi.fn();
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({ success: true }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+    localStorage.setItem('accessToken', 'token');
+
+    render(<ChangePasswordModal isOpen onClose={onClose} />);
+
+    fireEvent.change(screen.getByLabelText('Current Password'), {
+      target: { value: 'old-password' },
+    });
+    fireEvent.change(screen.getByLabelText('New Password'), {
+      target: { value: 'new-password' },
+    });
+    fireEvent.change(screen.getByLabelText('Confirm New Password'), {
+      target: { value: 'new-password' },
+    });
+
+    fireEvent.click(screen.getByRole('button', { name: 'Change Password' }));
+
+    await act(async () => {
+      await Promise.resolve();
+      await Promise.resolve();
+    });
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      '/api/auth/change-password',
+      expect.objectContaining({ method: 'POST' })
+    );
+
+    expect(screen.getByText('Password changed successfully!')).toBeInTheDocument();
+
+    act(() => {
+      vi.advanceTimersByTime(2000);
+    });
+
+    expect(onClose).toHaveBeenCalledTimes(1);
+  });
+
+  it('shows server error responses', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      json: async () => ({ error: 'Invalid password' }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+    localStorage.setItem('accessToken', 'token');
+
+    render(<ChangePasswordModal isOpen onClose={vi.fn()} />);
+
+    fireEvent.change(screen.getByLabelText('Current Password'), {
+      target: { value: 'old-password' },
+    });
+    fireEvent.change(screen.getByLabelText('New Password'), {
+      target: { value: 'new-password' },
+    });
+    fireEvent.change(screen.getByLabelText('Confirm New Password'), {
+      target: { value: 'new-password' },
+    });
+
+    fireEvent.click(screen.getByRole('button', { name: 'Change Password' }));
+
+    expect(await screen.findByText('Invalid password')).toBeInTheDocument();
+  });
+});