public void HappyPathTest()
        {
            var actualMpg = new MilesPerGallon {
                Miles = 540, Gallons = 18
            }.Mpg;
            var expectedMpg = 30.0;

            Assert.AreEqual(expectedMpg, actualMpg, 0.1);
        }
 public void ZeroGallonsExceptionTest()
 {
     var actualMpg = new MilesPerGallon {
         Miles = 540, Gallons = 0
     }.Mpg;
 }
 public void NegativeGallonsExceptionTest()
 {
     var actualMpg = new MilesPerGallon {
         Miles = 540, Gallons = -18
     }.Mpg;
 }