// (C) 2007-2019 GoodData Corporation
import { format } from "date-fns";
import { datesBetween } from "../datesBetween";

describe("datesBetween", () => {
    const formatDate = (date: Date) => format(date, "MM-DD-YYYY");

    it("should gen. sequence if dates are the same", () => {
        const startDate = new Date("01-01-2017");
        const finalDate = new Date("01-01-2017");

        const sequence = datesBetween(startDate, finalDate);

        expect(Array.from(sequence).map(formatDate)).toEqual(["01-01-2017"]);
    });

    it("should gen. sequence of dates between the starting and final date", () => {
        const startDate = new Date("01-01-2017");
        const finalDate = new Date("01-02-2017");

        const sequence = datesBetween(startDate, finalDate);

        expect(Array.from(sequence).map(formatDate)).toEqual(["01-01-2017", "01-02-2017"]);
    });

    it("should gen. sequence in such way, that the dates are not mutated", () => {
        const addOneDay = (date: Date) => date.setDate(date.getDate() + 1);

        const startDate = new Date("01-01-2017");
        const finalDate = new Date("01-03-2017");

        const sequence = datesBetween(startDate, finalDate);

        const firstDate = sequence.next().value;
        expect(formatDate(firstDate)).toEqual("01-01-2017");

        // If yield date wouldn't be cloned before yielding,
        // adding one day would modify internal date as well
        addOneDay(firstDate);

        const secondDate = sequence.next().value;
        expect(secondDate).not.toBeUndefined();
        expect(formatDate(secondDate)).toEqual("01-02-2017");
    });
});