[Newbies] capturing output in memory

[Mark Volkmann]

For the purpose of writing unit tests for code that writes to a stream  
I want to use something other than a FileStream that will allow me to  
write to it just like FileStream, but will just hold the data in  
memory. When I'm finished writing, I want to retrieve everything I've  
written as a single String. Is there a class that does that?

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Mark Volkmann