Displaying unit test trace output very slow in ReSharper 7.1?

In Visual Studio 2010/2012, after running an NUnit test that traces a lot of output (e.g. right click assembly, choose Run Unit Tests) I can then expand the Output tab in the Unit Test Session pane, and click on an individual test to see its output. For example, try making some tests that call this method:

private static void TraceSomething(int testNumber)


    for (var n = 0; n < 5000; n++)



            string.Format("Output line {0} from test {1}", n, testNumber).PadRight(200, '*'));



A lot of output (million characters), but in ReSharper 6.1 this was nice and fast. I can click on tests and so switch between the output of multiple tests almost instantly.

On upgrading to 7.1, I retry this and it is very much slower. I just timed it and it took two minutes to finish displaying the output of a single test that calls the TraceSomething method.

We need VS 2012 support so we are using 7.1 for that reason (note that the slow performance is the same in 2010 and 2012). Is there a chance that a forthcoming 7.x version could get back to being as fast as 6.x at displaying test trace output in VS?
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Hello Daniel
     Could you please capture a performance snapshot (using ReSharper | Help | Profile Visual Studio) of this behavior, click 'Get Snapshot' and then choose 'Send to JetBrains over ftp' option? This would really help us to investigate this problem further. Thank you!

Andrey Serebryansky

Software Developer

JetBrains, Inc


"Develop with pleasure!"


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