pairs.spec.js

/**************************
 *
 * THIS IS A TESTING FILE
 *
 * DO NOT MODIFY THIS FILE
 *
 ***************************/

import pairs from "./pairs";

describe("pairs()", () => {
  test("returns an empty array when passed nothing", () => {
    const result = pairs();
    expect(result).toEqual([]);
  });

  test("returns an empty array when passed an empty array", () => {
    const result = pairs([]);
    expect(result).toEqual([]);
  });

  test("returns an array with a single pair of items when passed an array with just two items", () => {
    const names = ["asis", "hamsa"];
    const result = pairs(names);
    expect(result.length).toBe(1);
    expect(result[0].length).toBe(2);
    expect(result[0].includes("asis")).toBe(true);
    expect(result[0].includes("hamsa")).toBe(true);
  });

  test("returns an array of pairs when passed multiple names", () => {
    const names = ["asis", "hamsa", "fawas", "mishmish"];
    const result = pairs(names);
    expect(result.length).toBe(2);
    expect(result.every(pair => pair.length == 2)).toBe(true);
  });

  test("is randomized", () => {
    let names = ["asis", "hamsa", "fawas", "mishmish"];
    let pairsets = [...Array(10)].map(() => pairs(names.slice(0)));
    expect(
      pairsets.every(
        pairset => JSON.stringify(pairset) === JSON.stringify(pairsets[0])
      )
    ).toBe(false);
  });

  test("can handle an odd number of names, the last array contains only one name", () => {
    let names = ["asis", "hamsa", "fawas", "mishmish", "hussein"];
    let result = pairs(names);
    expect(result.filter(pair => pair.length === 1).length).toBe(1);
  });
});