c# - 非虚拟成员的无效设置 - 在接口(interface)上？

Question

在使用 Moq 进行单元测试时，出现以下错误:

Message: System.NotSupportedException : 
    Invalid setup on non-virtual (overridable in VB) member: 
    cm => cm.AppSettings[It.IsAny<string>()]

根据这些发现，我了解到在 Moq 中使用抽象类或接口(interface)更可取。

• Why does the property I want to mock need to be virtual?
• Moq is throwing Invalid setup on a non-overridable member, when class is in Service Project
• Invalid setup on a non-virtual (overridable in VB) member
• Moq: Invalid setup on a non-overridable member: x => x.GetByTitle(“asdf”)

总之，我已经完成了作业。 =)

但如果我实际使用的是一个界面呢？

配置服务测试

[TestFixture]
public class ConfigurationServiceTests {
    [Test]
    public void DialectShouldQueryConfigurationManagerAppSettings() {
        // Given
        configurationManagerMock
            .Setup(cm => cm.AppSettings[It.IsAny<string>()])
            .Returns(It.IsAny<string>());

        // When
        var dialect = configurationService.Dialect;

        // Then
        dialect.Should().BeOfType<string>();
        configurationManagerMock.Verify(cm => cm.AppSettings[It.IsAny<string>()]);
    }

    [SetUp]
    public void ConfigurationServiceSetUp() {
        configurationManagerMock = new Mock<IConfigurationManager>();
        configurationService = 
            new ConfigurationService(configurationManagerMock.Object);
    }

    private Mock<IConfigurationManager> configurationManagerMock;
    private IConfigurationService configurationService;
}

IConfigurationManager

public interface IConfigurationManager {
    NameValueCollection AppSettings { get; }
    ConnectionStringSettingsCollection ConnectionStrings { get; }
}

IConfigurationService

public interface IConfigurationService {
    string ConnectionDriver { get; }
    string ConnectiongString { get; }
    string Dialect { get; }
}

配置服务

public class ConfigurationService : IConfigurationService {
    public ConfigurationService(IConfigurationManager configurationManager) {
        this.configurationManager = configurationManager;
    }

    public string ConnectionDriver {
        get { return configurationManager.AppSettings["ConnectionDriver"]; }
    }

    public string ConnectionString {
        get { 
            return configurationManager
                .ConnectionStrings[ConnectionStringKey]
                .ConnectionString; 
        }
    }

    public string Dialect { 
        get { return configurationManager.AppSettings[DialectKey]; } 
    }

    private readonly IConfigurationManager configurationManager;

    private const string ConnectionStringKey = "DefaultConnectionString";
    private const string DialectKey = "Dialect";
}

为什么要创建 IConfigurationManager 接口(interface)？

• Unit Testable Configuration Manager

除此之外，我想在我的生产代码中使用 Ninject 直接绑定(bind)它。所以我不需要接口(interface)的具体实现，因此我对上述异常感到非常惊讶。

kernel.Bind<IConfiguration>().To<ConfigurationManager>().InSingletonScope();

这样做可以让我对我的 ConfigurationService 进行单元测试。

有什么想法吗？

Answer 1

您正在尝试模拟 NameValueCollection 的索引器而不是你的属性(property) setter/getter 。

你需要做类似的事情(注意 SetupGet 而不是 Setup ):

  .SetupGet(cm => cm.AppSettings).Returns(....)

如果您想要返回“任何东西”的“模拟”集合，您可能需要覆盖实际类(检查是否有可能这样做)。

如果您知道要查找的设置 - 从 Mock 返回已填充的集合可能是一个选项:

 configurationManagerMock  
   .SetupGet(cm => cm.AppSettings)
   .Returns(new NameValueCollection { {"SettingName", "Value"}});

另一种选择是返回一些自定义界面或 IDictionary<string,string>所以你也可以模拟索引:

interface IConfigurationManager 
{
   IDictionary<string,string> AppSettings { get; }
   ...