Moq - 不能模拟 class 属性 的方法 return 值

Moq - Can't mock a class property's method return value

如何模拟 CasOperations.GetImpairedNodesFromCASpectrumAsync() 方法,使其 returns 成为模拟值?目前,我遇到异常(代码示例下方显示)。

我有以下设置:

Class 和 属性 被嘲笑:

public class BranchCircuitStatusScheduleEntry : NWatchCustomScheduleEntryBase, INWatchCustomScheduleEntry
{
    public BranchCircuitStatusScheduleEntry(INWatchSchedulerApplication application)
        : base(application, DevOpsScheduleFrequency.Minute, 15, 0, DevOpsScheduleFlags.Always)
    {
        // Some initialization for below properties
        CasOperations = new CasOperations(cas, EntityService, IsBranchesOnly);
    }

    public CasOperations CasOperations { get; private set; }

}

public class CasOperations
{
    public CasOperations(CasApi casApi, BranchCircuitEntityService entityService, bool isBranchesOnly)
    {
        CAS = casApi;
        this.entityService = entityService;
        this.isBranchesOnly = isBranchesOnly;
    }
}

尝试执行模拟的测试:

[TestMethod]
public void DownNodeRediscoveredInSpectrum()
{
    var mock = new Mock<BranchCircuitStatusScheduleEntry>(_application);
    mock.CallBase = true;

    // Spectrum's artificial response with a model with the same name, but a "new" model handle
    var mockedNewlyImpairedNodes = new NetworkDeviceNodeStatus[]
    {
        new NetworkDeviceNodeStatus
        {
            // Not important
        }
    };

    mock.Setup(x =>
        x.CasOperations.GetImpairedNodesFromCASpectrumAsync()).ReturnsAsync(mockedNewlyImpairedNodes);
}

测试抛出异常:

An exception of type 'Castle.DynamicProxy.InvalidProxyConstructorArgumentsException' occurred in Moq.dll but was not handled in user code Additional information: Can not instantiate proxy of class: NWatch.NetworkCircuits.CasOperations. Could not find a parameterless constructor.

请允许我试一试:

在模拟设置中,您不是要模拟 BranchCircuitStatusScheduleEntry 的行为,而是要模拟 CasOperations class 的行为。所以你真的需要一个 Mock<CasOperations> 对象。甚至更好,正如@Jonesopolis 在他的评论中所说的 Mock<ICasOperations>

此外,在 BranchCircuitStatusScheduleEntry 构造函数中,您正在初始化 class 的实例和 CasOperations 的实例。如果在 BranchCircuitStatusScheduleEntry 构造函数之外初始化 CasOperations 的实例并将其作为参数传递会更好。

所以它会是这样的:

public class BranchCircuitStatusScheduleEntry : NWatchCustomScheduleEntryBase, INWatchCustomScheduleEntry
{
    public BranchCircuitStatusScheduleEntry(INWatchSchedulerApplication application, ICasOperations casOperations)
        : base(application, DevOpsScheduleFrequency.Minute, 15, 0, DevOpsScheduleFlags.Always)
    {
        CasOperations = casoperations;
    }

    public CasOperations CasOperations { get; private set; }
}

最后,您创建模拟,设置它并将其作为参数传递给 BranchCircuitStatusScheduleEntry 构造函数:

var casMock = new Mock<ICasOperations>();
casMock.Setup(x => x.GetImpairedNodesFromCASpectrumAsync()).ReturnsAsync(mockedNewlyImpairedNodes);

var mock = new Mock<BranchCircuitStatusScheduleEntry>(_application, casMock.Object);
mock.CallBase = true;

请注意,也许 BranchCircuitStatusScheduleEntry 的最后一个实例不应该是模拟的,而是真实的对象(被测实例)。