public void ShouldCopyFile()
{
var a = Path.GetTempFileName();
var b = Path.GetTempFileName();
File.Delete(b);
const string expected = "blubb";
File.WriteAllText(a, expected);
_sut.CopyFile(a, b);
Assert.True(File.Exists(a));
Assert.True(File.Exists(b));
var actual = File.ReadAllText(b);
Assert.AreEqual(expected, actual);
}