CodeGo.net>如何使用Microsoft假冒垫片异步任务方法？

我正在使用Microsoft Fakes来填充异步方法,该方法调用另一个方法来获取已实现的DbContext.因为在async方法内部调用的方法需要它时,单元测试中没有提供数据库连接字符串. Shim不仅会跳过使用连接字符串的方法,还会返回可自定义的DbContext.

这是aysnc方法的实现：

public async Task<AccountDataDataContext> GetAccountDataInstance(int accountId)
{
    var account = await this.Accounts.FindAsync(accountId);

    return AccountDataDataContext.GetInstance(account.AccountDataConnectionString);
}

但是,我不熟悉Shim异步方法.我所做的看起来像这样：

ConfigurationEntities.Fakes.ShimConfigurationDataContext.AllInstances.GetAccountDataInstanceInt32NullableOfInt32 = (x, y, z) => new Task<AccountDataEntities.AccountDataDataContext>(() =>
{
    return new SampleContext();// This is the fake context I created for replacing the AccountDataDataContext.
});

SampleContext正在实现AccountDataDataContext,如下所示：

public class SampleContext: AccountDataDataContext
{
    public SampleContext()
    {
        this.Samples = new TestDbSet<Sample>();

        var data = new AccountDataRepository();

        foreach (var item in data.GetFakeSamples())
        {
            this.Samples.Add(item);
        }
    }
}

以下是测试案例的代码片段：

[TestMethod]
public async Task SampleTest()
{
    using (ShimsContext.Create())
    {
        //Arrange
        SamplesController controller = ArrangeHelper(1);// This invokes the Shim code pasted in the second block and returns SamplesController object in this test class

        var accountId = 1;
        var serviceId = 2;

        //Act
        var response = await controller.GetSamples(accountId, serviceId);// The async method is invoked in the GetSamples(int32, int32) method.

        var result = response.ToList();

        //Assert
        Assert.AreEqual(1, result.Count);
        Assert.AreEqual("body 2", result[0].Body);
    }
}

结果,我的测试用例永远运行.我认为我可能将Shim lamdas表达式完全写错了.

有什么建议吗？谢谢.

解决方法:

您不想返回新任务.实际上是you should never, ever use the Task constructor.正如我在博客中所描述的那样,它根本没有有效的用例.

而是使用Task.FromResult：

ConfigurationEntities.Fakes.ShimConfigurationDataContext.AllInstances.GetAccountDataInstanceInt32NullableOfInt32 =
    (x, y, z) => Task.FromResult(new SampleContext());

Task还具有其他一些From *方法,这些方法可用于单元测试(例如Task.FromException).

标签：asynchronous,shim,c,entity-framework
来源： https://codeday.me/bug/20191027/1942120.html