c# - CloudTableClient 单元测试

Question

如何为依赖于 Azure 表存储的类编写单元测试，即 Microsoft.Azure.Cosmos.Table.CloudTableClient ?

我发现了这个 GitHub 问题，Azure Storage is still hard to unit test / mock ，但除了现在的方法之外我没有找到任何线索 virtual .
MyService依赖于 CloudTableClient并在内部获得对 CloudTable 的引用查询表。在我的示例中，我正在按分区和行键进行简单的查找:

public MyService(CloudTableClient tableClient
            , ILogger<MyService> logger) { }

public async Task<MyMapping> GetMappingAsync(string rowKey)
{
    var table = GetTable();
    var retrieveOp = TableOperation.Retrieve<MyMapping>("MyPartitionKey", rowKey);
    var tableResult = await table.ExecuteAsync(retrieveOp);
    return tableResult.Result as MyMapping;
}

private CloudTable GetTable()
{
    return tableClient.GetTableReference("FakeTable");
}

Answer 1

为 CloudTable 创建模拟

覆盖 ExecuteAsync行为来自 Setup

为 CloudTableClient 创建模拟

覆盖 GetTableReference返回 CloudTable 的行为模拟通过 Setup

using Moq;
using Microsoft.Azure.Cosmos.Table;
using Microsoft.Extensions.Logging;

[TestInitialize]
public void InitTest()
{
    var cloudTableMock = new Mock<CloudTable>(new Uri("http://unittests.localhost.com/FakeTable")
        , (TableClientConfiguration)null);  //apparently Moq doesn't support default parameters 
                                            //so have to pass null here

    //control what happens when ExecuteAsync is called
    cloudTableMock.Setup(table => table.ExecuteAsync(It.IsAny<TableOperation>()))
        .ReturnsAsync(new TableResult());

    var cloudTableClientMock = new Mock<CloudTableClient>(new Uri("http://localhost")
        , new StorageCredentials(accountName: "blah", keyValue: "blah")
        , (TableClientConfiguration)null);  //apparently Moq doesn't support default parameters 
                                            //so have to pass null here

    //control what happens when GetTableReference is called
    cloudTableClientMock.Setup(client => client.GetTableReference(It.IsAny<string>()))
        .Returns(cloudTableMock.Object);

    var logger = Mock.Of<ILogger<MyService>>();
    myService = new MyService(cloudTableClientMock.Object, logger);
}

[TestMethod]
public async Task HelloWorldShouldReturnANullResult()
{
    //arrange
    var blah = "hello world";

    //act
    var result = await myService.GetMappingAsync(blah);

    //assert
    Assert.IsNull(result);
}