jest mocking

pastDeadline.test.js

require("../configure_enzyme");

//
// setup a mock for a function that depends on the current system time
//
import { pastDeadline } from "menu/pastDeadline";
jest.mock("menu/pastDeadline", () => {
  let areWePastDeadline = true;
  function __setPastDeadline(newValue) {
    areWePastDeadline = newValue;
  }

  return { __setPastDeadline, pastDeadline: () => areWePastDeadline };
});
import { __setPastDeadline } from "menu/pastDeadline";

test("__setPastDeadline back and forth in same test", () => {
  __setPastDeadline(false);
  expect(pastDeadline()).toBe(false);

  __setPastDeadline(true);
  expect(pastDeadline()).toBe(true);
});