import { isSorted } from "utils/isSorted";

describe("#isSorted", () => {
  it("empty list", () => {
    expect(isSorted([], (a: number, b: number) => a - b)).toEqual(true);
  });
  it("list with one element", () => {
    expect(isSorted([1], (a: number, b: number) => a - b)).toEqual(true);
  });
  it("list with two sorted elements", () => {
    expect(isSorted([1, 2], (a: number, b: number) => a - b)).toEqual(true);
  });
  it("list with two equal elements", () => {
    expect(isSorted([2, 2], (a: number, b: number) => a - b)).toEqual(true);
  });
  it("list with two unsorted elements", () => {
    expect(isSorted([2, 1], (a: number, b: number) => a - b)).toEqual(false);
  });
  it("list with many elements with one unsorted pair", () => {
    expect(
      isSorted([1, 2, 3, 4, 6, 5, 7], (a: number, b: number) => a - b)
    ).toEqual(false);
  });
  it("list with many elements with one unsorted pair at the end", () => {
    expect(
      isSorted([1, 2, 3, 4, 5, 7, 6], (a: number, b: number) => a - b)
    ).toEqual(false);
  });
  it("list with many elements with one unsorted pair at the beginning", () => {
    expect(
      isSorted([2, 1, 3, 4, 5, 6, 7], (a: number, b: number) => a - b)
    ).toEqual(false);
  });
  it("list with many elements with duplicates", () => {
    expect(
      isSorted([1, 2, 2, 3, 4, 5, 6, 7], (a: number, b: number) => a - b)
    ).toEqual(true);
  });
  it("list with opposite comparator", () => {
    expect(
      isSorted([1, 2, 2, 3, 4, 5, 6, 7], (a: number, b: number) => b - a)
    ).toEqual(false);
  });
  it("reverse sorted list with opposite comparator", () => {
    expect(
      isSorted(
        [1, 2, 2, 3, 4, 5, 6, 7].reverse(),
        (a: number, b: number) => b - a
      )
    ).toEqual(true);
  });
});