public async void ThenReturnEmptyEnumerableGivenInvalidDirectory()
            {
                // Arrange
                var info = new DirectoryInfo(string.Format("Bad{0}", TestDirectoryRoot));
                var asyncResult = info.SafeEnumerateDirectoriesAsync();

                // Act
                var directories = await asyncResult;

                // Assert
                Assert.That(directories, Is.EqualTo(Enumerable.Empty<DirectoryInfo>()));
            }
            public async void ThenShouldReturnEnumerableDirectoriesAsyncGivenPathWithSubDirectories()
            {
                // Arrange
                var info = new DirectoryInfo(TestDirectoryRoot);
                var asyncResult = info.SafeEnumerateDirectoriesAsync();

                // Act
                var directories = await asyncResult;

                // Assert
                Assert.That(directories, Is.EquivalentTo(_directoryList.Select(s => new DirectoryInfo(s))));
            }