Make setting the "Chosen Item" in a <input type="file"> easier #190

        protected static IHtmlInputElement FindInputElement(IRenderedComponent<CascadingAuthenticationState> cut, string findFrom = @"input")
        {
            return ((AngleSharpWrappers.Wrapper<AngleSharp.Dom.IElement>)cut.Find(findFrom)).WrappedElement as AngleSharp.Html.Dom.IHtmlInputElement;
        }

        protected async Task<FileInfo> AddFileToAsync(IRenderedComponent<CascadingAuthenticationState> cut, string fileName, string findFrom = @"input", string type = @"text/csv")
        {
            var inputLoading = FindInputElement(cut, findFrom);
            (Context.Services.GetService<IFileReaderService>() as MockIFileReaderService).SetInput(inputLoading);
            var fi = new FileInfo(fileName);
            inputLoading.Files.Add(new InputFile(fi.Name, type, fi.OpenRead(), fi.LastWriteTimeUtc));
            await inputLoading.ChangeAsync(new ChangeEventArgs());
            return fi;
        }

        [Test]
        public async Task A020_UpLoadEnvironmentPage()
        {
            const string TESTDATA_METOCEAN1_CSV = @"TestData/metocean1.csv";

            var cut = RenderComponent<CascadingAuthenticationState>(x => x
                .AddChildContent<UploadEnvironment>(parameters => parameters.Add(p => p.AssetId, AssetId)));
            var uploadBut = cut.Find(@"button"); // There is only one
            uploadBut.HasAttribute(@"disabled").Should().BeTrue();
            uploadBut.TextContent.Should().BeEquivalentTo(@"Upload");

            FileInfo fi = await AddFileToAsync(cut, TESTDATA_METOCEAN1_CSV);

            uploadBut.HasAttribute(@"disabled").Should().BeFalse();
            await cut.Find(@"form").SubmitAsync();

           // Some other magic happens here to get the ingestMessage from the target

            await using var streamFile = new FileStream(fi.FullName, FileMode.Open, FileAccess.Read, FileShare.None, 1024 * 32,
                /*FileOptions.DeleteOnClose |*/ FileOptions.Asynchronous | FileOptions.SequentialScan);
            (await new StreamCompare().AreEqualAsync(streamFile, ingestMessage.stream, null)).Should().BeTrue();
        }