C# AutoFixture.AutoMoq为一个构造函数参数提供已知值

我刚刚开始在单元测试中使用AutoFixture.AutoMoq，我发现它对于创建不关心特定值的对象非常有用。毕竟，匿名对象创建就是它的全部内容

当我关心一个或多个构造器参数时，我正在努力解决这个问题。以下面的组件为例：

public class ExampleComponent
{
    public ExampleComponent(IService service, string someValue)
    {
    }
}

我想编写一个测试，其中我为

someValue

提供了一个特定的值，但将

IService

留给AutoFixture.AutoMoq自动创建

我知道如何在我的

iTexture

上使用

Freeze

来保持将注入组件的已知值，但我不太明白如何提供自己的已知值

以下是我理想情况下想要做的：

[TestMethod]
public void Create_ExampleComponent_With_Known_SomeValue()
{
    // create a fixture that supports automocking
    IFixture fixture = new Fixture().Customize(new AutoMoqCustomization());

    // supply a known value for someValue (this method doesn't exist)
    string knownValue = fixture.Freeze<string>("My known value");

    // create an ExampleComponent with my known value injected 
    // but without bothering about the IService parameter
    ExampleComponent component = this.fixture.Create<ExampleComponent>();

    // exercise component knowning it has my known value injected
    ...
}

我正在实现一个

CookieCache

，其中

ITypeConverter

处理对象与字符串之间的转换，并使用

lifespan

设置cookie的到期日期

public class CookieCache : ICache
{
    public CookieCache(ITypeConverter converter, TimeSpan lifespan)
    {
        // usual storing of parameters
    }

    public bool TryRead<T>(string key, out T result)
    {
        // read the cookie value as string and convert it to the target type
    }

    public void Write<T>(string key, T value)
    {
        // write the value to a cookie, converted to a string

        // set the expiry date of the cookie using the lifespan
    }

    // other methods not shown...
}

公共类CookieCache:ICache
{
公共CookieCache（ITypeConverter转换器，时间跨度寿命）
{
//参数的常规存储
}
公共bool TryRead（字符串键，out T结果）
{
//以字符串形式读取cookie值并将其转换为目标类型
}
公共无效写入（字符串键，T值）
{
//将值写入cookie，并转换为字符串
//使用寿命设置cookie的到期日期
}
//其他方法未显示。。。
}

因此，在编写cookie有效期测试时，我关心的是寿命，而不是转换器。

您必须更换：

string knownValue = fixture.Freeze<string>("My known value");

您可以阅读有关

Inject

的更多信息

---

实际上，

Freeze

扩展方法可以：

var value = fixture.Create<T>();
fixture.Inject(value);
return value;

var value=fixture.Create（）；
夹具。注入（值）；
返回值；

这意味着您在测试中使用的重载实际上使用seed:My known value调用了

Create

，结果是“My known value4d41f94f-1fc9-4115-9f29-e50bc2b4ba5e”

你可以这样做。假设您想为名为

lifespan

的

TimeSpan

参数指定一个特定值

public class LifespanArg : ISpecimenBuilder
{
    private readonly TimeSpan lifespan;

    public LifespanArg(TimeSpan lifespan)
    {
        this.lifespan = lifespan;
    }

    public object Create(object request, ISpecimenContext context)
    {
        var pi = request as ParameterInfo;
        if (pi == null)
            return new NoSpecimen(request);

        if (pi.ParameterType != typeof(TimeSpan) ||
            pi.Name != "lifespan")   
            return new NoSpecimen(request);

        return this.lifespan;
    }
}

必要的是，它可以这样使用：

var fixture = new Fixture();
fixture.Customizations.Add(new LifespanArg(mySpecialLifespanValue));

var sut = fixture.Create<CookieCache>();

var fixture=newfixture（）；
fixture.Customizations.Add（newlifespanarg（mySpecialLifespanValue））；
var sut=fixture.Create（）；

---

这种方法在某种程度上可以推广，但最终，我们受到了限制，因为缺乏从特定构造函数或方法参数中提取参数信息的强类型方法。

因此，我相信人们可以解决Mark建议的推广实现，但我想我会发表评论

我根据Mark的

LifeSpanArg

，创建了一个通用

参数NameSpecimenBuilder

：

public class ParameterNameSpecimenBuilder<T> : ISpecimenBuilder
{
    private readonly string name;
    private readonly T value;

    public ParameterNameSpecimenBuilder(string name, T value)
    {
        // we don't want a null name but we might want a null value
        if (string.IsNullOrWhiteSpace(name))
        {
            throw new ArgumentNullException("name");
        }

        this.name = name;
        this.value = value;
    }

    public object Create(object request, ISpecimenContext context)
    {
        var pi = request as ParameterInfo;
        if (pi == null)
        {
            return new NoSpecimen(request);
        }

        if (pi.ParameterType != typeof(T) ||
            !string.Equals(
                pi.Name, 
                this.name, 
                StringComparison.CurrentCultureIgnoreCase))
        {
            return new NoSpecimen(request);
        }

        return this.value;
    }
}

以下测试现在将通过：

[TestMethod]
public void FreezeByName_Sets_Value1_And_Value2_Independently()
{
    //// Arrange
    IFixture arrangeFixture = new Fixture();

    string myValue1 = arrangeFixture.Create<string>();
    string myValue2 = arrangeFixture.Create<string>();

    IFixture sutFixture = new Fixture();
    sutFixture.FreezeByName("value1", myValue1);
    sutFixture.FreezeByName("value2", myValue2);

    //// Act
    TestClass<string> result = sutFixture.Create<TestClass<string>>();

    //// Assert
    Assert.AreEqual(myValue1, result.Value1);
    Assert.AreEqual(myValue2, result.Value2);
}

public class TestClass<T>
{
    public TestClass(T value1, T value2)
    {
        this.Value1 = value1;
        this.Value2 = value2;
    }

    public T Value1 { get; private set; }

    public T Value2 { get; private set; }
}

[TestMethod]
公共名称\u独立设置\u值1\u和\u值2\u（）
{
////安排
iTexture arrangeFixture=新夹具（）；
字符串myValue1=arrangeFixture.Create（）；
字符串myValue2=arrangeFixture.Create（）；
iTexture sutFixture=新夹具（）；
sutFixture.FriezByName（“value1”，myValue1）；
sutFixture.FriezByName（“value2”，myValue2）；
////表演
TestClass结果=sutFixture.Create（）；
////断言
arest.AreEqual（myValue1，result.Value1）；
Assert.AreEqual（myValue2，result.Value2）；
}
公共类TestClass
{
公共测试类（T值1，T值2）
{
此值为1.Value1=Value1；
此参数为0.Value2=Value2；
}
公共T值1{get；私有集；}
公共T值2{get；私有集；}
}

我觉得@Nick就快到了。重写构造函数参数时，它需要用于给定类型，并且仅限于该类型

首先，我们创建一个新的ISpecimenBuilder，它查看“Member.DeclaringType”以保持正确的范围

public class ConstructorArgumentRelay<TTarget,TValueType> : ISpecimenBuilder
{
    private readonly string _paramName;
    private readonly TValueType _value;

    public ConstructorArgumentRelay(string ParamName, TValueType value)
    {
        _paramName = ParamName;
        _value = value;
    }

    public object Create(object request, ISpecimenContext context)
    {
        if (context == null)
            throw new ArgumentNullException("context");
        ParameterInfo parameter = request as ParameterInfo;
        if (parameter == null)
            return (object)new NoSpecimen(request);
        if (parameter.Member.DeclaringType != typeof(TTarget) ||
            parameter.Member.MemberType != MemberTypes.Constructor ||
            parameter.ParameterType != typeof(TValueType) ||
            parameter.Name != _paramName)
            return (object)new NoSpecimen(request);
        return _value;
    }
}

public类构造函数argumentrelay:ISpecimenBuilder
{
私有只读字符串_paramName；
私有只读TValueType_值；
公共构造函数ArgumentRelay（字符串参数名、TValueType值）
{
_paramName=paramName；
_价值=价值；
}
公共对象创建（对象请求，ISPecementContext上下文）
{
if（上下文==null）
抛出新的ArgumentNullException（“上下文”）；
ParameterInfo参数=请求作为ParameterInfo；
if（参数==null）
返回（对象）新的NoSpecimen（请求）；
if（parameter.Member.DeclaringType！=typeof（TTarget）||
parameter.Member.MemberType！=MemberTypes.Constructor||
parameter.ParameterType！=typeof（TValueType）||
parameter.Name！=\u paramName）
返回（对象）新的NoSpecimen（请求）；
返回_值；
}
}

接下来，我们创建一个扩展方法，使我们能够轻松地将其与AutoFixture连接起来

public static class AutoFixtureExtensions
{
    public static IFixture ConstructorArgumentFor<TTargetType, TValueType>(
        this IFixture fixture, 
        string paramName,
        TValueType value)
    {
        fixture.Customizations.Add(
           new ConstructorArgumentRelay<TTargetType, TValueType>(paramName, value)
        );
        return fixture;
    }
}

公共静态类AutoFixtureExtensions
{
公共静态iTexture构造函数参数(
这个IFixture夹具，
字符串参数名，
TValueType（类型值）
{
fixture.Customizations.Add(
新建构造函数ArgumentRelay（参数名、值）
);
返回夹具；
}
}

现在我们创建两个类似的类来进行测试

    public class TestClass<T>
    {
        public TestClass(T value1, T value2)
        {
            Value1 = value1;
            Value2 = value2;
        }

        public T Value1 { get; private set; }
        public T Value2 { get; private set; }
    }

    public class SimilarClass<T>
    {
        public SimilarClass(T value1, T value2)
        {
            Value1 = value1;
            Value2 = value2;
        }

        public T Value1 { get; private set; }
        public T Value2 { get; private set; }
    }

公共类TestClass
{
公共测试类（T值1，T值2）
{
Value1=Value1；
Value2=Value2；
}
公共T值1{get；私有集；}
公共T值2{get；私有集；}
}
公共类相似类
{
公共相似类（T值1，T值2）
{
Value1=Value1；
Value2=Value2；
}
公共T值1{get；私有集；}
公共T值2{get；私有集；}
}

最后我们测试

public class ConstructorArgumentRelay<TTarget,TValueType> : ISpecimenBuilder
{
    private readonly string _paramName;
    private readonly TValueType _value;

    public ConstructorArgumentRelay(string ParamName, TValueType value)
    {
        _paramName = ParamName;
        _value = value;
    }

    public object Create(object request, ISpecimenContext context)
    {
        if (context == null)
            throw new ArgumentNullException("context");
        ParameterInfo parameter = request as ParameterInfo;
        if (parameter == null)
            return (object)new NoSpecimen(request);
        if (parameter.Member.DeclaringType != typeof(TTarget) ||
            parameter.Member.MemberType != MemberTypes.Constructor ||
            parameter.ParameterType != typeof(TValueType) ||
            parameter.Name != _paramName)
            return (object)new NoSpecimen(request);
        return _value;
    }
}

public static class AutoFixtureExtensions
{
    public static IFixture ConstructorArgumentFor<TTargetType, TValueType>(
        this IFixture fixture, 
        string paramName,
        TValueType value)
    {
        fixture.Customizations.Add(
           new ConstructorArgumentRelay<TTargetType, TValueType>(paramName, value)
        );
        return fixture;
    }
}

    public class TestClass<T>
    {
        public TestClass(T value1, T value2)
        {
            Value1 = value1;
            Value2 = value2;
        }

        public T Value1 { get; private set; }
        public T Value2 { get; private set; }
    }

    public class SimilarClass<T>
    {
        public SimilarClass(T value1, T value2)
        {
            Value1 = value1;
            Value2 = value2;
        }

        public T Value1 { get; private set; }
        public T Value2 { get; private set; }
    }

[TestFixture]
public class AutoFixtureTests
{
    [Test]
    public void Can_Create_Class_With_Specific_Parameter_Value()
    {
        string wanted = "This is the first string";
        string wanted2 = "This is the second string";
        Fixture fixture = new Fixture();
        fixture.ConstructorArgumentFor<TestClass<string>, string>("value1", wanted)
               .ConstructorArgumentFor<TestClass<string>, string>("value2", wanted2);

        TestClass<string> t = fixture.Create<TestClass<string>>();
        SimilarClass<string> s = fixture.Create<SimilarClass<string>>();

        Assert.AreEqual(wanted,t.Value1);
        Assert.AreEqual(wanted2,t.Value2);
        Assert.AreNotEqual(wanted,s.Value1);
        Assert.AreNotEqual(wanted2,s.Value2);
    }        
}

internal sealed class CustomConstructorBuilder<T> : ISpecimenBuilder
{
    private readonly Dictionary<string, object> _ctorParameters = new Dictionary<string, object>();

    public object Create(object request, ISpecimenContext context)
    {
        var type = typeof (T);
        var sr = request as SeededRequest;
        if (sr == null || !sr.Request.Equals(type))
        {
            return new NoSpecimen(request);
        }

        var ctor = type.GetConstructors(BindingFlags.Instance | BindingFlags.Public).FirstOrDefault();
        if (ctor == null)
        {
            return new NoSpecimen(request);
        }

        var values = new List<object>();
        foreach (var parameter in ctor.GetParameters())
        {
            if (_ctorParameters.ContainsKey(parameter.Name))
            {
                values.Add(_ctorParameters[parameter.Name]);
            }
            else
            {
                values.Add(context.Resolve(parameter.ParameterType));
            }
        }

        return ctor.Invoke(BindingFlags.CreateInstance, null, values.ToArray(), CultureInfo.InvariantCulture);
    }

    public void Addparameter(string paramName, object val)
    {
        _ctorParameters.Add(paramName, val);
    }
 }

   public static class AutoFixtureExtensions
    {
        public static void FreezeActivator<T>(this IFixture fixture, object parameters)
        {
            var builder = new CustomConstructorBuilder<T>();
            foreach (var prop in parameters.GetType().GetProperties())
            {
                builder.Addparameter(prop.Name, prop.GetValue(parameters));
            }

            fixture.Customize<T>(x => builder);
        }
    }

var f = new Fixture();
f.FreezeActivator<UserInfo>(new { privateId = 15, parentId = (long?)33 });

var sut = new Fixture()
    .For<AClass>()
    .Set("value1").To(aInterface)
    .Set("value2").ToEnumerableOf(22, 33)
    .Create();

public class AClass
{
    public AInterface Value1 { get; private set; }
    public IEnumerable<int> Value2 { get; private set; }

    public AClass(AInterface value1, IEnumerable<int> value2)
    {
        Value1 = value1;
        Value2 = value2;
    }
}

public interface AInterface
{
}

public class ATest
{
    [Theory, AutoNSubstituteData]
    public void ATestMethod(AInterface aInterface)
    {
        var sut = new Fixture()
            .For<AClass>()
            .Set("value1").To(aInterface)
            .Set("value2").ToEnumerableOf(22, 33)
            .Create();

        Assert.True(ReferenceEquals(aInterface, sut.Value1));
        Assert.Equal(2, sut.Value2.Count());
        Assert.Equal(22, sut.Value2.ElementAt(0));
        Assert.Equal(33, sut.Value2.ElementAt(1));
    }
}

public static class AutoFixtureExtensions
{
    public static SetCreateProvider<TTypeToConstruct> For<TTypeToConstruct>(this IFixture fixture)
    {
        return new SetCreateProvider<TTypeToConstruct>(fixture);
    }
}

public class SetCreateProvider<TTypeToConstruct>
{
    private readonly IFixture _fixture;

    public SetCreateProvider(IFixture fixture)
    {
        _fixture = fixture;
    }

    public SetProvider<TTypeToConstruct> Set(string parameterName)
    {
        return new SetProvider<TTypeToConstruct>(this, parameterName);
    }

    public TTypeToConstruct Create()
    {
        var instance = _fixture.Create<TTypeToConstruct>();
        return instance;
    }

    internal void AddConstructorParameter<TTypeOfParam>(ConstructorParameterRelay<TTypeToConstruct, TTypeOfParam> constructorParameter)
    {
        _fixture.Customizations.Add(constructorParameter);
    }
}

public class SetProvider<TTypeToConstruct>
{
    private readonly string _parameterName;
    private readonly SetCreateProvider<TTypeToConstruct> _father;

    public SetProvider(SetCreateProvider<TTypeToConstruct> father, string parameterName)
    {
        _parameterName = parameterName;
        _father = father;
    }

    public SetCreateProvider<TTypeToConstruct> To<TTypeOfParam>(TTypeOfParam parameterValue)
    {
        var constructorParameter = new ConstructorParameterRelay<TTypeToConstruct, TTypeOfParam>(_parameterName, parameterValue);
        _father.AddConstructorParameter(constructorParameter);
        return _father;
    }

    public SetCreateProvider<TTypeToConstruct> ToEnumerableOf<TTypeOfParam>(params TTypeOfParam[] parametersValues)
    {
        IEnumerable<TTypeOfParam> actualParamValue = parametersValues;
        var constructorParameter = new ConstructorParameterRelay<TTypeToConstruct, IEnumerable<TTypeOfParam>>(_parameterName, actualParamValue);
        _father.AddConstructorParameter(constructorParameter);
        return _father;
    }
}

public class ConstructorParameterRelay<TTypeToConstruct, TValueType> : ISpecimenBuilder
{
    private readonly string _paramName;
    private readonly TValueType _paramValue;

    public ConstructorParameterRelay(string paramName, TValueType paramValue)
    {
        _paramName = paramName;
        _paramValue = paramValue;
    }

    public object Create(object request, ISpecimenContext context)
    {
        if (context == null)
            throw new ArgumentNullException(nameof(context));
        ParameterInfo parameter = request as ParameterInfo;
        if (parameter == null)
            return new NoSpecimen();
        if (parameter.Member.DeclaringType != typeof(TTypeToConstruct) ||
            parameter.Member.MemberType != MemberTypes.Constructor ||
            parameter.ParameterType != typeof(TValueType) ||
            parameter.Name != _paramName)
            return new NoSpecimen();
        return _paramValue;
    }
}