如何以适当的方式使用Ninject测试.net项目

Question

We have a project with separated bussiness layer. It's like lots of services (classes) in separated project in the solution. Also we use ninject to manage dependancies. All classes in bussiness layes project are internal, and it communicates with «another world» through interfaces. If to create new project that would contain test then it wont see internal classes (but yeah we can do a hack and declare Internal to Public in AsseblyInfo).

What i really need to know is what's neccessary to test:

1. We can create test envirement of everything, and test only through produced interfaces (there is no «clear» DAL, we are using linq2sql, but its possible to be mocked) This way looks goods, because we know nothing about internal BisLayer structure and test only «contract» functionality. But the bad side is that the system has lots of options, settings and bindings and it seems impossible or pretty hard to check all possible variants of it

2. We can place tests in the same project or set attribute to make internal being seen as public, so we'd be able to test internal classes. Its good because we can test almost everything, but its hard to control bindings, cos it'd be nice Ninject to do it, and we would only override bindings we need in concret test. Also its not clear how to test classes implementing the same interface (and doing similar things). Like we have few implementations of Cache but each impl-tion keeps data in different places (mssql, key-value db, asp cache, etc), so tests for each implementation actually would be the same

Answer 1

As you say you need to have access to the classes in order to test. So, make only the internals that are exposed to the outside trough interfaces accessible from the outside.

Write your tests only against the behaviour that is exposed to the outside, "another world" as you call it. Write the more generic test cases first and the go into details as needed. As this will be an ongoing process together with the development/change of the actual functionality you'll the be able to decide how many fine grained scenarios you actually need.

Also take a look at Ninject Mocking Kernel extension https://github.com/ninject/ninject.mockingkernel