JS-Testing: leap year parameterized spec

leap_year.param.spec.js

describe('leap year specs', () => {
  describe('A year is a leap year if', () => {
    it.each(
      [2016, 1984, 4]
    )(
      'it is divisible by 4 but not by 100 (eg. %i)',
      year => expect(isLeapYear(year)).toBeTruthy()
    );
    it.each(
      [2400, 2000, 400]
    )('it is divisible by 400 (eg. %i)',
      year => expect(isLeapYear(year)).toBeTruthy()
    );
  });