Mocking out SPFarm

Hi,

According to the code you posted, you seem to be misusing SwapNextInstance - SwapNextInstance replaces objects instantiated in the code under test, while SPFarm.Local is a static call. You only need to set

Isolate.Swap.NextInstance<SPFarm>().With(fakeFarm); 

With this:

Isolate.WhenCalled(() => SPFarm.Local).WillReturn(fakeFarm);

I quickly ran your code locally and that seemed to help; please let me know if this works on your end.
Thanks,
Doron
Typemock Support

Doron

Thanks that fixed the problem.

It does raise a question in my mind as I am trying to get a clear picture of when to use one form of fake over another:

As I have the Isolate attribute set on each test I thought that whole Typemock system was reset for each test so....

As there is only one call to SPFarm.Local in the code per test why is the Swap.NextInstance() not equivalent to the WhenCalled() ?

They both work for single tests, but not the batch so is my assumption that the Isolate attribute resets everything incorrect?

Thanks

Richard

Richard,

You are right in that the Isolate attribute resets fake behavior between each and every test. However, SwapNextInstance<T> is triggered if and only if a constructor for T has been called. It is not equivalent to WhenCalled() but rather complementing.

Generally speaking, you set behaviors on your fake object (or static methods) using WhenCalled() and then you can choose how to inject that fake behavior to the code under test:
- If the code under test receives a reference to the fake behavior, you just pass it in.
- If the code under tests receives it from a third party, you fake that third party to return the fake object you set up.
- If the code under test uses 'new' to instantiate the dependent behavior, use SwapNextInstance to replace the next 'new' with the faked object

Hope this clears things up.
Doron
Typemock Support

Thanks it does

Richard