使用VS2012单元测试有一种方法可以创建一个对象并设置其私有字段而无需构造函数

Question

So I'm getting in Unit Testing and I'm using the built-in framework with Visual Studio 2012 called Unit Test.

I've got some objects I need to mock up (I think..)

There is a method that takes some parameters and returns an IEnumerable of resource objects which I want to compare in a deterministic way to a list/array of objects I create. The problem the resource object I want to create has a constructor that takes arguments, performs its magic on them and then sets properties that I've marked as

{ get; private set; }

With the properties not having public setters, is there a way I can just set them so I can compare the result of the method to my 'oracle' list that I hand made?

Taking a step back,

1. is this the right way to approach unit testing a method that returns this type of object?
2. Am I using the wrong type of object in my program under test?
3. Continuing - should it just have a 0 argument constructor?

Thanks!

Answer 1

Does the comparison of the objects rely on data that is not publicly available (private or protected fields)? If not, you could just assert that all fields are what you expect them to be.

I guess the right approach would be to have your resource implement an interface IResource that derives from IEquatable and implement that interface in a mock or stub object you create in your test method.

I am not convinced though that it is a good practice to unit test something as trivial as resource loading in depth. You could also just check if you get a certain number of items, none of the is null and assume everything works. Might be easier than to adapt your unit test every time a resource changes.

Answer 2

See below answers to your questions:

1. is this the right way to approach unit testing a method that returns this type of object? --> I don't see anything wrong with what you have described but if you provide code then I can take a look
2. Am I using the wrong type of object in my program under test? --> Same as above
3. Continuing - should it just have a 0 argument constructor? --> I don't see anything wrong with having arguments in constructor

Now to your original question, you can use PrivateObject to set property with private setter like done in below link: http://akurniaga.wordpress.com/tag/unit-test-privateobject-visual-studio/

You should also look at Moq or any other mocking framework for mocking the objects.