Тестирование навигации и SearchParams

[Тестовый контекст: Vitest + React Testing Library]
       │
       ├─► Мокирование хуков next/navigation:
       │   - useSearchParams()  ──► new URLSearchParams('category=dev&page=2')
       │   - usePathname()      ──► '/catalog'
       │   - useRouter()        ──► { push: vi.fn(), replace: vi.fn() }
       │
       ▼
+-------------------------------------------------------------------------------+
|                Клиентский компонент: <CatalogFilters />                       |
+-------------------------------------------------------------------------------+
       │
       ├─► Чтение начального состояния: category = 'dev', page = 2
       │
       ▼ (Пользователь меняет сортировку: userEvent.selectOptions)
+-------------------------------------------------------------------------------+
|                       Мутация URLSearchParams                                 |
|                       const params = new URLSearchParams(searchParams)        |
|                       params.set('sort', 'price_asc')                         |
|                       params.delete('page') // Сброс пагинации на 1           |
+-------------------------------------------------------------------------------+
       │
       ▼
+-------------------------------------------------------------------------------+
|                Вызов router.push('/catalog?' + params.toString())             |
+-------------------------------------------------------------------------------+
       │
       ▼
[Ассерт в тесте: expect(router.push).toHaveBeenCalledWith('/catalog?category=dev&sort=price_asc')]

import { vi } from 'vitest';

export interface NavigationMockState {
  pathname?: string;
  searchParams?: Record<string, string>;
  params?: Record<string, string>;
}

export function setupNavigationMock(initialState: NavigationMockState = {}) {
  const push = vi.fn();
  const replace = vi.fn();
  const back = vi.fn();
  const forward = vi.fn();
  const refresh = vi.fn();
  const prefetch = vi.fn();

  const pathname = initialState.pathname ?? '/';
  const urlSearchParams = new URLSearchParams(initialState.searchParams ?? {});
  const routeParams = initialState.params ?? {};

  const useRouterMock = vi.fn(() => ({
    push,
    replace,
    back,
    forward,
    refresh,
    prefetch,
  }));

  const useSearchParamsMock = vi.fn(() => urlSearchParams);
  const usePathnameMock = vi.fn(() => pathname);
  const useParamsMock = vi.fn(() => routeParams);

  vi.mock('next/navigation', () => ({
    useRouter: useRouterMock,
    useSearchParams: useSearchParamsMock,
    usePathname: usePathnameMock,
    useParams: useParamsMock,
  }));

  return {
    push,
    replace,
    back,
    refresh,
    pathname,
    urlSearchParams,
    useRouterMock,
    useSearchParamsMock,
  };
}

'use client';

import { usePathname, useRouter, useSearchParams } from 'next/navigation';
import { ChangeEvent } from 'react';

export function CatalogSort() {
  const router = useRouter();
  const pathname = usePathname();
  const searchParams = useSearchParams();

  const handleSortChange = (event: ChangeEvent<HTMLSelectElement>) => {
    const nextSort = event.target.value;

    // Создаем изменяемую копию текущих параметров URL
    const nextParams = new URLSearchParams(searchParams.toString());

    if (nextSort) {
      nextParams.set('sort', nextSort);
    } else {
      nextParams.delete('sort');
    }

    // При смене сортировки обязательно сбрасываем номер страницы
    nextParams.delete('page');

    const queryString = nextParams.toString();
    const targetUrl = queryString ? `${pathname}?${queryString}` : pathname;

    router.push(targetUrl, { scroll: false });
  };

  const currentSort = searchParams.get('sort') || '';

  return (
    <div className="sort-wrapper">
      <label htmlFor="sort-select">Сортировка:</label>
      <select
        id="sort-select"
        value={currentSort}
        onChange={handleSortChange}
        data-testid="sort-select"
      >
        <option value="">По умолчанию</option>
        <option value="price_asc">Сначала дешевле</option>
        <option value="price_desc">Сначала дороже</option>
        <option value="popular">По популярности</option>
      </select>
    </div>
  );
}

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { CatalogSort } from './CatalogSort';
import { useRouter, useSearchParams, usePathname } from 'next/navigation';

vi.mock('next/navigation', () => ({
  useRouter: vi.fn(),
  useSearchParams: vi.fn(),
  usePathname: vi.fn(),
}));

describe('CatalogSort (Client Navigation)', () => {
  const mockPush = vi.fn();

  beforeEach(() => {
    vi.clearAllMocks();
    vi.mocked(useRouter).mockReturnValue({
      push: mockPush,
      replace: vi.fn(),
      back: vi.fn(),
      forward: vi.fn(),
      refresh: vi.fn(),
      prefetch: vi.fn(),
    });
    vi.mocked(usePathname).mockReturnValue('/catalog/phones');
  });

  it('обновляет параметр sort и удаляет page при выборе новой сортировки', async () => {
    const user = userEvent.setup();

    // Начальный URL: /catalog/phones?brand=apple&page=3
    vi.mocked(useSearchParams).mockReturnValue(
      new URLSearchParams('brand=apple&page=3') as unknown as ReturnType<typeof useSearchParams>
    );

    render(<CatalogSort />);

    const select = screen.getByLabelText(/сортировка/i);
    expect(select).toHaveValue('');

    // Пользователь выбирает сортировку "Сначала дешевле"
    await user.selectOptions(select, 'price_asc');

    // Проверяем, что router.push вызван с сохраненным brand, обновленным sort и удаленным page
    expect(mockPush).toHaveBeenCalledTimes(1);
    expect(mockPush).toHaveBeenCalledWith(
      '/catalog/phones?brand=apple&sort=price_asc',
      { scroll: false }
    );
  });

  it('удаляет параметр sort из URL, если выбрано значение по умолчанию', async () => {
    const user = userEvent.setup();

    // Начальный URL содержит sort
    vi.mocked(useSearchParams).mockReturnValue(
      new URLSearchParams('brand=samsung&sort=popular') as unknown as ReturnType<typeof useSearchParams>
    );

    render(<CatalogSort />);

    const select = screen.getByLabelText(/сортировка/i);
    expect(select).toHaveValue('popular');

    // Сбрасываем на "По умолчанию"
    await user.selectOptions(select, '');

    expect(mockPush).toHaveBeenCalledWith(
      '/catalog/phones?brand=samsung',
      { scroll: false }
    );
  });
});

import { Metadata } from 'next';
import { getArticleBySlug } from '@/dal/articles';

export interface ArticlePageProps {
  params: Promise<{ slug: string }>;
  searchParams: Promise<{ preview?: string }>;
}

export async function generateMetadata({
  params,
  searchParams,
}: ArticlePageProps): Promise<Metadata> {
  // Асинхронное получение параметров в Next.js 16
  const { slug } = await params;
  const { preview } = await searchParams;

  const article = await getArticleBySlug(slug, preview === 'true');

  if (!article) {
    return {
      title: 'Статья не найдена | Fullstack Agentic Lab',
      description: 'Запрашиваемый материал отсутствует в базе знаний.',
      robots: { index: false, follow: false },
    };
  }

  return {
    title: `${article.title} | Fullstack Agentic Lab`,
    description: article.summary,
    alternates: {
      canonical: `https://agenticlab.dev/articles/${article.slug}`,
    },
    openGraph: {
      title: article.title,
      description: article.summary,
      url: `https://agenticlab.dev/articles/${article.slug}`,
      type: 'article',
      images: [
        {
          url: article.coverImage,
          width: 1200,
          height: 630,
          alt: article.title,
        },
      ],
    },
  };
}

export default async function ArticlePage({ params }: ArticlePageProps) {
  const { slug } = await params;
  return <article>Статья {slug}</article>;
}

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { generateMetadata } from './page';
import * as articlesDal from '@/dal/articles';

vi.mock('@/dal/articles', () => ({
  getArticleBySlug: vi.fn(),
}));

describe('generateMetadata (Dynamic SEO Tags)', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  it('формирует корректные OpenGraph и Canonical метатеги для найденной статьи', async () => {
    vi.mocked(articlesDal.getArticleBySlug).mockResolvedValue({
      id: 'art-1',
      slug: 'testing-nextjs-rsc',
      title: 'Тестирование React Server Components',
      summary: 'Глубокий гайд по тестированию асинхронных RSC и DAL в Next.js 16',
      coverImage: 'https://agenticlab.dev/images/og-rsc.png',
    });

    const metadata = await generateMetadata({
      params: Promise.resolve({ slug: 'testing-nextjs-rsc' }),
      searchParams: Promise.resolve({}),
    });

    expect(metadata.title).toBe('Тестирование React Server Components | Fullstack Agentic Lab');
    expect(metadata.description).toBe('Глубокий гайд по тестированию асинхронных RSC и DAL в Next.js 16');
    expect(metadata.alternates?.canonical).toBe('https://agenticlab.dev/articles/testing-nextjs-rsc');

    // Проверяем OpenGraph протокол
    expect(metadata.openGraph).toMatchObject({
      title: 'Тестирование React Server Components',
      type: 'article',
      url: 'https://agenticlab.dev/articles/testing-nextjs-rsc',
      images: [
        {
          url: 'https://agenticlab.dev/images/og-rsc.png',
          width: 1200,
          height: 630,
        },
      ],
    });
  });

  it('возвращает noindex метатеги, если сущность не найдена', async () => {
    vi.mocked(articlesDal.getArticleBySlug).mockResolvedValue(null);

    const metadata = await generateMetadata({
      params: Promise.resolve({ slug: 'missing-article' }),
      searchParams: Promise.resolve({}),
    });

    expect(metadata.title).toBe('Статья не найдена | Fullstack Agentic Lab');
    expect(metadata.robots).toEqual({ index: false, follow: false });
  });
});