AutoFixture.AutoMoq提供一个已知值一个构造函数的参数 [英] AutoFixture.AutoMoq supply a known value for one constructor parameter

问题描述

我刚刚开始使用 AutoFixture.AutoMoq 在我的单元测试，我发现，用于创建，我并不关心具体的值对象，它非常有帮助。毕竟，匿名对象的创建是它的全部。

I've just started to use AutoFixture.AutoMoq in my unit tests and I'm finding it very helpful for creating objects where I don't care about the specific value. After all, anonymous object creation is what it is all about.

当我关心的构造函数的参数中的一个或多个我正在挣扎的。以 ExampleComponent 如下：

What I'm struggling with is when I care about one or more of the constructor parameters. Take ExampleComponent below:

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

我想写一个测试，我为 someValue中提供一个特定的值，但将 IService 来可以通过自动生成的 AutoFixture.AutoMoq

I want to write a test where I supply a specific value for someValue but leave IService to be created automatically by AutoFixture.AutoMoq.

我知道如何使用冻结上我的 IFixture 来保持一个已知值将被注入到一个组件的电话，但我不能完全看到怎样的电源的一个已知的值。我自己

I know how to use Freeze on my IFixture to keep hold of a known value that will be injected into a component but I can't quite see how to supply a known value of my own.

下面是我理想的情况喜欢做的事：

Here is what I would ideally like to do:

[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
    ...
}

我知道我可以通过直接调用构造函数做到这一点，但是这将不再是匿名的对象的创建。有没有使用 AutoFixture.AutoMock 这样的方式还是我需要把一个DI容器到我的测试，能够做我想要什么？

I know I could do this by calling the constructor directly but this would no longer be anonymous object creation. Is there a way to use AutoFixture.AutoMock like this or do I need to incorporate a DI container into my tests to be able to do what I want?

编辑：

我也许应该已经在我原来的问题少absract所以这里是我的具体情况。

I probably should have been less absract in my original question so here is my specific scenario.

我有一个具有通用的 ICACHE 接口 TryRead< ; T> 和写< T> 方法：

I have an ICache interface which has generic TryRead<T> and Write<T> methods:

public interface ICache
{
    bool TryRead<T>(string key, out T value);

    void Write<T>(string key, T value);

    // other methods not shown...  
}

我实施 CookieCache ，其中 ITypeConverter 处理的对象转换成与字符串和寿命用来设置cookie的到期日

I'm implementing a CookieCache where ITypeConverter handles converting objects to and from strings and lifespan is used to set the expiry date of a cookie.

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...
}

因此，对于一个cookie的到期日编写测试的时候，我关心的寿命，但没有这么多的转换器。

So when writing a test for the expiry date of a cookie, I care about the lifespan but not so much about the converter.

推荐答案

您必须更换：

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

与

with:

fixture.Inject("My known value");

您可以阅读更多关于注入 这里。

You can read more about Inject here.

其实，冻结扩展方法做：

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

这意味着你在测试中居然叫创建中所使用的过载; T> ; 用的种子：我的已知值的造成的我知value4d41f94f-1fc9-4115-9f29-e50bc2b4ba5e的。

Which means that the overload you used in the test actually called Create<T> with a seed: My known value resulting in "My known value4d41f94f-1fc9-4115-9f29-e50bc2b4ba5e".

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