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/app/setup/steps/BookDateStep.test.tsx

@@ -0,0 +1,179 @@
+/**
+ * Component: Setup BookDate Step Tests
+ * Documentation: documentation/setup-wizard.md
+ */
+
+// @vitest-environment jsdom
+
+import React, { useState } from 'react';
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { BookDateStep } from '@/app/setup/steps/BookDateStep';
+
+const BookDateHarness = ({
+  onNext,
+  onSkip,
+  onBack,
+  initialState,
+}: {
+  onNext: () => void;
+  onSkip: () => void;
+  onBack: () => void;
+  initialState?: Partial<React.ComponentProps<typeof BookDateStep>>;
+}) => {
+  const [state, setState] = useState({
+    bookdateProvider: 'openai',
+    bookdateApiKey: '',
+    bookdateModel: '',
+    bookdateConfigured: false,
+    ...initialState,
+  });
+
+  return (
+    <BookDateStep
+      {...state}
+      onUpdate={(field, value) => setState((prev) => ({ ...prev, [field]: value }))}
+      onNext={onNext}
+      onSkip={onSkip}
+      onBack={onBack}
+    />
+  );
+};
+
+describe('BookDateStep', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it('disables connection test when API key is missing', async () => {
+    render(
+      <BookDateHarness onNext={vi.fn()} onSkip={vi.fn()} onBack={vi.fn()} />
+    );
+
+    expect(screen.getByRole('button', { name: /Test Connection/ })).toBeDisabled();
+  });
+
+  it('fetches models and proceeds after successful test', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        models: [
+          { id: 'model-1', name: 'Model One' },
+        ],
+      }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+    const onNext = vi.fn();
+
+    render(
+      <BookDateHarness
+        onNext={onNext}
+        onSkip={vi.fn()}
+        onBack={vi.fn()}
+        initialState={{ bookdateApiKey: 'key' }}
+      />
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: /Test Connection/ }));
+
+    await waitFor(() => {
+      expect(fetchMock).toHaveBeenCalledWith('/api/bookdate/test-connection', expect.any(Object));
+    });
+
+    expect(await screen.findByText('Select Model')).toBeInTheDocument();
+
+    const nextButton = screen.getByRole('button', { name: 'Next' });
+    await waitFor(() => {
+      expect(nextButton).not.toBeDisabled();
+    });
+    fireEvent.click(nextButton);
+    expect(onNext).toHaveBeenCalled();
+  });
+
+  it('shows an error when the connection test fails', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      json: async () => ({ error: 'Invalid API key' }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    render(
+      <BookDateHarness
+        onNext={vi.fn()}
+        onSkip={vi.fn()}
+        onBack={vi.fn()}
+        initialState={{ bookdateApiKey: 'bad-key' }}
+      />
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: /Test Connection/ }));
+
+    await waitFor(() => {
+      expect(screen.getByText('Invalid API key')).toBeInTheDocument();
+    });
+  });
+
+  it('auto-selects the first model and shows the note', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        models: [
+          { id: 'model-1', name: 'Model One' },
+          { id: 'model-2', name: 'Model Two' },
+        ],
+      }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    render(
+      <BookDateHarness
+        onNext={vi.fn()}
+        onSkip={vi.fn()}
+        onBack={vi.fn()}
+        initialState={{ bookdateApiKey: 'key' }}
+      />
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: /Test Connection/ }));
+
+    await waitFor(() => {
+      expect(screen.getByText('Select Model')).toBeInTheDocument();
+    });
+
+    const selects = screen.getAllByRole('combobox');
+    const modelSelect = selects[1];
+    expect(modelSelect).toHaveValue('model-1');
+    expect(screen.getByText(/Library scope and custom prompt preferences/)).toBeInTheDocument();
+  });
+
+  it('clears tested state and models when switching providers', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        models: [{ id: 'model-1', name: 'Model One' }],
+      }),
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    render(
+      <BookDateHarness
+        onNext={vi.fn()}
+        onSkip={vi.fn()}
+        onBack={vi.fn()}
+        initialState={{ bookdateApiKey: 'key' }}
+      />
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: /Test Connection/ }));
+
+    await waitFor(() => {
+      expect(screen.getByText('Select Model')).toBeInTheDocument();
+    });
+
+    const providerSelect = screen.getAllByRole('combobox')[0];
+    fireEvent.change(providerSelect, { target: { value: 'claude' } });
+
+    expect(screen.queryByText('Select Model')).not.toBeInTheDocument();
+    expect(screen.getByRole('button', { name: 'Next' })).toBeDisabled();
+  });
+});