public async Task InsertFileToRoot(
     [Values("a", "b", "a/b", "b/c", "d/a")]
     string fileName,
     [Values("ahh", "nahh", "wahh")] string fileContents)
 {
     dummyFileLoader.InsertAt(fileName, fileContents);
     Assert.AreEqual(
         fileContents, await dummyFileLoader.LoadStringAt(fileName));
 }
 public async Task LoadsStringAtImmediate() =>
 Assert.AreEqual(
     "the letter a", await dummyFileLoader.LoadStringAt("a.txt"));