Question

我编写了以下测试，尝试使用.NET 4.5中提供的新的async / await关键字：

    [Test]
    public async void DefaultFilesValid()
    {
        LogTest(log);
        var libraryTasks = new List<Task<string>>();
        foreach (var def in LibrariesModel.LibraryDefinitions)
        {
            IViewModel viewModel = (IViewModel)ReflectionUtility.CreateNew(def.ModelType);
            var libraries = def.LibraryFiles.Where(f => def.IsDefaultFile(f)).ToArray();
            foreach(var library in libraries)
            {
                var libraryTask = LoadEmbeddedLibraryAsync(viewModel, library);
                libraryTasks.Add(libraryTask);
            }
        }

        // Wait for the results
        var libraryErrors = await Task.WhenAll(libraryTasks);
        var errors = libraryErrors.SelectMany(m => m);
        Assert.True(!errors.Any(), String.Join(Environment.NewLine, errors));
    }

    private async Task<string> LoadEmbeddedLibraryAsync(IViewModel viewModel, string library)
    {
        return await Task.Factory.StartNew<string>(() =>
        {
            var libraryDef = viewModel.Library;
            var libraryMessage = String.Format("The default library '{0}' of the type '{1}' ", library, libraryDef.LibraryName);
            try
            {
                // Open the library
                viewModel.Open(library, library: true);

                // Check that the hash is as expected
                var fileHash = libraryDef.GetDefaultFileHash(library);
                var hash = viewModel.Source.GetStatewiseHashCode().ToString();
                if (fileHash != hash)
                    return libraryMessage + String.Format("has been modified, model hash was '{0}' but '{1}' was expected.", hash, fileHash);
            }
            catch (Exception ex)
            {
                return String.Format("failed to open: {0}", ExceptionUtility.JoinExceptionMessages(ex));
            }
            return null;
        });
    }

然而，代码是同步执行的，有人可以解释一下我做错了吗？

谢谢，亚历克斯。

Answer 1

将您的单元测试从async void更改为async Task。 NUnit仅支持v2.6.2以后的async void单元测试，并且仅支持v2.9.6 for v3（v3中的支持已在v2.9.7中删除）。 async void测试要求NUnit提供一个特殊的上下文，它会改变await（可能还有StartNew的行为，虽然我还没有测试过。）

作为旁注：

使用Task.Run代替Task.Factory.StartNew。我有一篇描述why。
使用Task.Run 调用方法，而不是实现（假）异步方法。我有另一篇博客文章描述why。

C＃NUnit没有异步运行测试

1 个答案: