@shopify/jest-koa-mocks/src/create-mock-cookies/create-mock-cookies.ts

import {Context} from 'koa';

export type Cookies = Context['cookies'];

export interface Dictionary<T> {
  [key: string]: T;
}

export interface MockCookies extends Cookies {
  requestStore: Map<string, string>;
  responseStore: Map<string, string>;
}

export default function createMockCookies(
  cookies = {},
  secure = true,
): MockCookies {
  const cookieEntries = Object.keys(cookies).map(
    key => [key, cookies[key]] as [string, string],
  );

  const requestStore = new Map<string, string>(cookieEntries);
  const responseStore = new Map<string, string>(cookieEntries);

  return {
    set: jest.fn((key, value) => {
      return responseStore.set(key, value);
    }),
    get: jest.fn(key => {
      return requestStore.get(key);
    }),
    requestStore,
    responseStore,
    secure,
  } as any;
}