Re: How do I unit test a Dispose method ?

On 3 February 2014 14:39, Amir Kolsky <[email protected]> wrote:

>
>
>  This only applies to objects that it owns. Otherwise if it dispose of a
> reference that has been passed to it (say through injection) then it may be
> closing an object that is still required elsewhere.
>
>
>
> Which is the problem with IDisposable to begin with. It is well-nigh
> impossible to define the behavior properly.
>

I agree that it is difficult. Here is the test list that I used:


   - when the Finalizer is called it releases all unmanaged resources
   - when the Finalizer is called it does NOT Dispose its managed resources
   (remember that the order of finalization is not guaranteed, so the managed
   resource may already have been finalized)
   - when Dispose() is called all unmanaged resources are released
   - when Dispose() is called all managed Disposable objects are Disposed

To conform to the IDisposable design
pattern<http://msdn.microsoft.com/en-us/library/system.idisposable(v=vs.110).aspx>,
the target class must also:

   - implement IDisposable
   - provide a protected virtual Dispose(bool disposing) method
   - the Dispose() method must call Dispose(true)
   - the Dispose() method must suppress finalization
   - if a finalizer is needed, it must call Dispose(false)
   - handle Dispose() being called multiple times
   - throw an ObjectDisposedException in any other public method tries to
   access disposed objects


Some of these were challenging (or impossible) to write automated tests
for, some were just messy.