random util needs more tests for decimals

[user24]

e.g this fails but is not in test suite yet

  it('should be inclusive of min and max (10,20)', function () {
    let tries = 1000;
    let hadMin = false;
    let hadMax = false;

    while (tries-- && (!hadMin || !hadMax)) {
      const r = randBetween(10, 20, true);
      hadMin = hadMin || r === 10;
      hadMax = hadMax || r === 20;
    }

    assert(hadMin, 'min');
    assert(hadMax, 'max');
  });