使用 Moq 模拟时模拟 returns null

Question

我可能遗漏了一些明显的东西。使用 Asp.Net 核心后台服务。简化设置如下：

SUT

public class OrderService: BaseOrderService 
{
    IConsumer<string, string> _consumer;

    public OrderService(IBuilder consumerBuilder, ILogger logger) : base(logger)
    {
        _consumer = consumerBuilder.Build(() => Provider);
    }
}

public abstract class BaseOrderService: BackgroundService
{
    protected BaseOrderService(ILogger logger){}

    ....
    ....
}

IBuilder

public interface IBuilder
{
    IConsumer<string, string> Build(Func<string> providerFunc);
}

单元测试

[Fact]
public async Task TestDescription()
{
    var mockBuilder = new Mock<IBuilder>();
    var mockConsumer = new Mock<IConsumer<string, string>>();
    mockBuilder.Setup(x => x.Build(It.IsAny<string>)).Returns(mockConsumer.Object);

    var sut = new OrderService(mockBuilder.Object, NullLogger.Instance);
    await sut.StartAsync(default);
    ....
    ....
}

问题

根据运行我的测试，在 OrderService 构造函数中调用 _consumer = _consumerBuilder.Build(()=> Provider) returns null，尽管我已经在中提供了模拟设置测试。

我错过了什么？任何指针将不胜感激。

Answer 1

使用了错误的参数匹配器。

被嘲笑的成员期望Func<string>

IConsumer<string, string> Build(Func<string> providerFunc);

但是你的代码设置 It.IsAny<string>

mockBuilder
    .Setup(x => x.Build(It.IsAny<string>)) //<-- WRONG
    .Returns(mockConsumer.Object);

应该是It.IsAny<Func<string>>()

 mockBuilder
    .Setup(x => x.Build(It.IsAny<Func<string>>())) //<--
    .Returns(mockConsumer.Object);

使用 Moq 模拟时模拟 returns null

Mock returns null when mocking using Moq

c#

moq

xunit

asp.net-core

asp.net-core-hosted-services