public void TestDefaultFormatException(long millis, string format)
        {
            var sw = new Stopwatch();

            SetElapsedTime(sw, millis);

            Assert.Throws <FormatException>(() => sw.DefaultFormat(format));
        }
        public void TestDefaultFormat(long millis, string format, string expected)
        {
            var sw = new Stopwatch();

            SetElapsedTime(sw, millis);

            sw.DefaultFormat(format);

            var actual = sw.ElapsedFormat();

            actual.Should().Be(expected);
        }