axios-cache-interceptor/test/mocks/axios.ts

import Axios from 'axios';
import type { AxiosCacheInstance, CacheRequestConfig } from '../../src/cache/axios';
import { CacheOptions, setupCache } from '../../src/cache/create';
import { Header } from '../../src/header/headers';

export const XMockRandom = 'x-mock-random';

export function mockAxios(
  options: CacheOptions = {},
  responseHeaders: Record<string, string> = {},
  instance = Axios.create()
): AxiosCacheInstance {
  const axios = setupCache(instance, options);

  // Axios interceptors are a stack, so apply this after the cache interceptor
  axios.defaults.adapter = async (config) => {
    await 0; // Jumps to next tick of nodejs event loop

    const should304: unknown =
      config.headers?.[Header.IfNoneMatch] || config.headers?.[Header.IfModifiedSince];
    const status = should304 ? 304 : 200;

    if (config.validateStatus?.(status) === false) {
      throw {
        id: (config as CacheRequestConfig).id,
        config,
        request: { config },
        response: {
          data: true,
          status,
          statusText: should304 ? '304 Not Modified' : '200 OK',
          headers: {
            ...responseHeaders,
            // Random header for every request made
            [XMockRandom]: `${Math.random()}`
          },
          config,
          request: { config }
        }
      };
    }

    return {
      data: true,
      status,
      statusText: should304 ? '304 Not Modified' : '200 OK',
      headers: {
        ...responseHeaders,
        // Random header for every request made
        [XMockRandom]: `${Math.random()}`
      },
      config,
      request: { config }
    };
  };

  return axios;
}