jestTestDST.js

// jest tests

describe("getTickValues method", () => {
  const dispformat = "DD-MMM-YYYY hh:mm";

  beforeAll(() => {
    moment.tz.setDefault("Europe/London");
  });

  it("generates tick values with DST", () => {
    const d1 = new Date("2017-10-29T00:26:00Z"); //UTC time
    const d2 = new Date("2017-10-29T02:12:00Z"); //UTC time
    const expectedValue = "29-Oct-2017 01:00";

    expect(moment(getDSTDate(d1, d2)).format(dispformat)).toEqual(
      expectedValue
    );
  });

  afterAll(() => {
    moment.tz.setDefault();
  });
});