public void DeleteTest()
        {
            var name = @"z:\temp\aaa.txt";
            var file = new FileEmu();
            file.AddFile(name, "あいうえお", Encoding.GetEncoding("shift-jis"));

            Assert.IsTrue(file.Exists(name));
            file.Delete(name);
            Assert.IsFalse(file.Exists(name));
        }