permutateWithRepetitions.test.js

import permutateWithRepetitions from '../permutateWithRepetitions';

describe('permutateWithRepetitions', () => {
  it('should permutate string with repetition', () => {
    const permutations1 = permutateWithRepetitions(['A']);
    expect(permutations1).toEqual([
      ['A'],
    ]);

    const permutations2 = permutateWithRepetitions(['A', 'B']);
    expect(permutations2).toEqual([
      ['A', 'A'],
      ['A', 'B'],
      ['B', 'A'],
      ['B', 'B'],
    ]);

    const permutations3 = permutateWithRepetitions(['A', 'B', 'C']);
    expect(permutations3).toEqual([
      ['A', 'A', 'A'],
      ['A', 'A', 'B'],
      ['A', 'A', 'C'],
      ['A', 'B', 'A'],
      ['A', 'B', 'B'],
      ['A', 'B', 'C'],
      ['A', 'C', 'A'],
      ['A', 'C', 'B'],
      ['A', 'C', 'C'],
      ['B', 'A', 'A'],
      ['B', 'A', 'B'],
      ['B', 'A', 'C'],
      ['B', 'B', 'A'],
      ['B', 'B', 'B'],
      ['B', 'B', 'C'],
      ['B', 'C', 'A'],
      ['B', 'C', 'B'],
      ['B', 'C', 'C'],
      ['C', 'A', 'A'],
      ['C', 'A', 'B'],
      ['C', 'A', 'C'],
      ['C', 'B', 'A'],
      ['C', 'B', 'B'],
      ['C', 'B', 'C'],
      ['C', 'C', 'A'],
      ['C', 'C', 'B'],
      ['C', 'C', 'C'],
    ]);

    const permutations4 = permutateWithRepetitions(['A', 'B', 'C', 'D']);
    expect(permutations4.length).toBe(4 * 4 * 4 * 4);
  });
});