有没有办法模拟Azure CloudQueueClient或CloudQueue？

Question

我正在为我的代码编写单元测试,并且遇到了一个方法,在尝试创建队列和AddMessage到队列时会抛出StorageException.我想测试异常处理是否正常.为了做到这一点,我想到了为CloudQueue使用模拟,但后来发现这个类是密封的.有没有办法在不实际更改生产代码的情况下测试异常处理(或强制执行StorageException)？

Answer 1

处理这个的最简单的方法是使用一个接口CloudQueueClient(这是@tyrion建议的),在上面..但也是一个接口ICloudQueue

public interface ICloudQueueClientWrapper
{
    ICloudQueueWrapper GetQueueReference(string queueName);
}

// ----------------

public class CloudQueueClientWrapper : ICloudQueueClientWrapper
{
    private readonly Lazy<CloudQueueClient> _cloudQueueClient;

    public CloudQueueClientWrapper(string connectionStringName)
    {
        connectionStringName.ShouldNotBeNullOrWhiteSpace();

        _cloudQueueClient = new Lazy<CloudQueueClient>(() =>
        {
            // We first need to connect to our Azure storage.
            var storageConnectionString = CloudConfigurationManager.GetSetting(connectionStringName);
            var storageAccount = CloudStorageAccount.Parse(storageConnectionString);

            // Create the queue client.
            return storageAccount.CreateCloudQueueClient();
        });
    }

    public ICloudQueueWrapper GetQueueReference(string queueName)
    {
        queueName.ShouldNotBeNullOrWhiteSpace();

        var cloudQueue = _cloudQueueClient.Value.GetQueueReference(queueName);
        return new CloudQueueWrapper(cloudQueue);
    }

    // Add more methods here which are a one-to-one match against the underlying CQC.
}

所以这是第一个接口和包装器...并注意这会返回一个ICloudQueue实例..所以现在让我们这样做......

public interface ICloudQueueWrapper
{
    Task AddMessageAsync(CloudQueueMessage message);
}

public class CloudQueueWrapper : ICloudQueueWrapper
{
    private readonly CloudQueue _cloudQueue;

    public CloudQueueWrapper(CloudQueue cloudQueue)
    {
        cloudQueue.ShouldNotBeNull();

        _cloudQueue = cloudQueue;
    }

    public async Task AddMessageAsync(CloudQueueMessage message)
    {
        message.ShouldNotBeNull();

        await _cloudQueue.AddMessageAsync(message);
    }
}

好的...所以现在让我们尝试在一些单元测试中使用它:)

    [Theory]
    [MemberData(nameof(StockIds))]
    public async Task GivenSomeData_DoFooAsync_AddsDataToTheQueue(string[] stockIds)
    {
        // Arrange.
        var cloudQueue = Mock.Of<ICloudQueueWrapper>();
        var cloudQueueClient = Mock.Of<ICloudQueueClientWrapper>();
        Mock.Get(cloudQueueClient).Setup(x => x.GetQueueReference(It.IsAny<string>()))
            .Returns(cloudQueue);
        var someService = new SomeService(cloudQueueClient);

        // Act.
        await someService.DoFooAsync(Session);

        // Assert.
        // Did we end up getting a reference to the queue?
        Mock.Get(cloudQueueClient).Verify(x => x.GetQueueReference(It.IsAny<string>()), Times.Once);

        // Did we end up adding something to the queue?
        Mock.Get(cloudQueue).Verify(x => x.AddMessageAsync(It.IsAny<CloudQueueMessage>()), Times.Exactly(stockids.Length));
    }

Answer 2

过去，我们使用 Microsoft Fakes 框架来对类似的 Azure SDK 类进行单元测试。前面有一点学习曲线，但效果很好。

https://msdn.microsoft.com/en-us/library/hh549175.aspx