memory-infrastructure-palace/code/websites/pokedex.online/tests/unit/utilities/api-client.test.js

import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { createApiClient } from '@/utilities/api-client';

describe('api-client', () => {
  let fetchMock;

  beforeEach(() => {
    fetchMock = vi.fn();
    global.fetch = fetchMock;
  });

  afterEach(() => {
    vi.clearAllTimers();
    vi.unstubAllGlobals();
  });

  describe('createApiClient', () => {
    it('should create client with default config', () => {
      const client = createApiClient();
      expect(client).toHaveProperty('get');
      expect(client).toHaveProperty('post');
      expect(client).toHaveProperty('put');
      expect(client).toHaveProperty('patch');
      expect(client).toHaveProperty('delete');
    });

    it('should merge baseURL with request path', async () => {
      const client = createApiClient({ baseURL: '/api' });
      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => ({ success: true })
      });

      await client.get('/users');

      expect(fetchMock).toHaveBeenCalledWith(
        '/api/users',
        expect.objectContaining({ method: 'GET' })
      );
    });
  });

  describe('GET requests', () => {
    it('should make successful GET request', async () => {
      const client = createApiClient();
      const mockData = { id: 1, name: 'Test' };

      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => mockData
      });

      const result = await client.get('/test');

      expect(result).toEqual(mockData);
      expect(fetchMock).toHaveBeenCalledWith(
        '/test',
        expect.objectContaining({
          method: 'GET',
          headers: expect.objectContaining({
            'Content-Type': 'application/json'
          })
        })
      );
    });

    it('should handle non-JSON responses', async () => {
      const client = createApiClient();
      const textResponse = 'Plain text response';

      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'text/plain' }),
        text: async () => textResponse
      });

      const result = await client.get('/text');

      expect(result).toBe(textResponse);
    });
  });

  describe('POST requests', () => {
    it('should make POST request with data', async () => {
      const client = createApiClient();
      const postData = { name: 'Test' };
      const mockResponse = { id: 1, ...postData };

      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => mockResponse
      });

      const result = await client.post('/users', postData);

      expect(result).toEqual(mockResponse);
      expect(fetchMock).toHaveBeenCalledWith(
        '/users',
        expect.objectContaining({
          method: 'POST',
          body: JSON.stringify(postData)
        })
      );
    });
  });

  describe('error handling', () => {
    it('should throw error on HTTP error status', async () => {
      const client = createApiClient();
      const errorResponse = { message: 'Not found' };

      fetchMock.mockResolvedValueOnce({
        ok: false,
        status: 404,
        statusText: 'Not Found',
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => errorResponse
      });

      await expect(client.get('/missing')).rejects.toThrow('HTTP 404');
    });

    it('should not retry on 4xx errors', async () => {
      const client = createApiClient({ maxRetries: 3 });

      fetchMock.mockResolvedValueOnce({
        ok: false,
        status: 400,
        statusText: 'Bad Request',
        headers: new Headers(),
        json: async () => ({})
      });

      await expect(client.get('/bad')).rejects.toThrow();
      expect(fetchMock).toHaveBeenCalledTimes(1);
    });

    it('should retry on 5xx errors', async () => {
      vi.useFakeTimers();
      const client = createApiClient({ maxRetries: 2, retryDelay: 100 });

      fetchMock
        .mockResolvedValueOnce({
          ok: false,
          status: 500,
          statusText: 'Internal Server Error',
          headers: new Headers(),
          json: async () => ({})
        })
        .mockResolvedValueOnce({
          ok: false,
          status: 500,
          statusText: 'Internal Server Error',
          headers: new Headers(),
          json: async () => ({})
        })
        .mockResolvedValueOnce({
          ok: true,
          headers: new Headers({ 'content-type': 'application/json' }),
          json: async () => ({ success: true })
        });

      const promise = client.get('/retry');

      // Advance timers for retries
      await vi.runAllTimersAsync();

      const result = await promise;

      expect(result).toEqual({ success: true });
      expect(fetchMock).toHaveBeenCalledTimes(3);

      vi.useRealTimers();
    });
  });

  describe('request deduplication', () => {
    it('should deduplicate identical concurrent requests', async () => {
      const client = createApiClient();
      const mockData = { data: 'test' };

      fetchMock.mockResolvedValue({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => mockData
      });

      // Make two identical concurrent requests
      const [result1, result2] = await Promise.all([
        client.get('/test'),
        client.get('/test')
      ]);

      expect(result1).toEqual(mockData);
      expect(result2).toEqual(mockData);
      expect(fetchMock).toHaveBeenCalledTimes(1); // Only one actual fetch
    });

    it('should allow disabling deduplication', async () => {
      const client = createApiClient();

      fetchMock.mockResolvedValue({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => ({ data: 'test' })
      });

      await Promise.all([
        client.get('/test', { deduplicate: false }),
        client.get('/test', { deduplicate: false })
      ]);

      expect(fetchMock).toHaveBeenCalledTimes(2);
    });
  });

  describe('interceptors', () => {
    it('should call onRequest interceptor', async () => {
      const onRequest = vi.fn((url, options) => options);
      const client = createApiClient({ onRequest });

      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => ({})
      });

      await client.get('/test');

      expect(onRequest).toHaveBeenCalledWith(
        '/test',
        expect.objectContaining({ method: 'GET' })
      );
    });

    it('should call onResponse interceptor', async () => {
      const onResponse = vi.fn();
      const client = createApiClient({ onResponse });

      fetchMock.mockResolvedValueOnce({
        ok: true,
        headers: new Headers({ 'content-type': 'application/json' }),
        json: async () => ({}),
        clone: function () {
          return this;
        }
      });

      await client.get('/test');

      expect(onResponse).toHaveBeenCalled();
    });

    it('should call onError interceptor', async () => {
      vi.useFakeTimers();
      const onError = vi.fn();
      const client = createApiClient({ onError, maxRetries: 0 });

      fetchMock.mockResolvedValueOnce({
        ok: false,
        status: 500,
        statusText: 'Server Error',
        headers: new Headers(),
        json: async () => ({})
      });

      await expect(client.get('/error')).rejects.toThrow();
      expect(onError).toHaveBeenCalled();

      vi.useRealTimers();
    });
  });
});