public void WhenStartOne_AndMultiplierTwo_ThenReturnSequence(int size, int lastValue)
            {
                var result = Sequencer.Geometric(size, 1, 2);

                Assert.That(result.Count, Is.EqualTo(size));
                Assert.That(result.Last(), Is.EqualTo(lastValue));
            }
            public void WhenSizeIsZeroOrLess_ThenReturnEmpty(int size)
            {
                var result = Sequencer.Geometric(size, 1, 2);

                Assert.That(result, Is.Empty);
            }
 public void WhenStartIsZero_ThenThrowException()
 {
     Assert.Throws <ArgumentException>(() => Sequencer.Geometric(10, 0, 2));
 }