The stakeholder wants the application data to be stored as XML in a plain text file that could be read by a tool like notepad - not totally unreasonable. But that causes a problem when testing my CRUD methods. A test must write something to the XML file then read it back in to check that it was written correctly. However, that invariably raises an IOException complainig, that "some other process" is accessing the file. Of course the "other process" is in fact my test process. The section in the NCrunch Docs about concurrency talks about <ExclusivelyUses...> and <Serializable...>, but none of that helps, if the process is interfering with itself.

This must be a pretty common problem, but I haven't been able to come up with a working solution. Anybody got an idea here?

I am reading the XML stream with an XMLReader created with XMLReader.Create(Path) and writing to the XML stream with an XMLTextWriter created like so:
Dim Enc As Encoding = New UnicodeEncoding()
Out = New StreamWriter(FullPath)
Writer = New XmlTextWriter(Out.BaseStream, Enc)

I had naively been assuming that it would suffice to close both streams after use, but your question alerted me to the fact that I may also have to do a dispose on each stream after closing it.
However, that does not seem to solve the problem. I´m still getting an IOException when trying to read fom the XMLStream after writing, closing and disposing it. The message of the IOException still says another process is using that file. Weird!