Pex - Automated Exploratory Testing for .NET

Posted By: Brian Keller | Jul 3rd @ 10:56 AM

Pex is a tool being developed by Microsoft Research which has the potential to dramatically improve the quality of software testing while requiring minimal, if any, effort on the part of the developer. Pex can automatically generate a set of inputs for a paramaterized unit test which can effectively excercise most, if not all, possible code paths.

I visited Nikolai Tillmann and Peli de Halleux on the Pex team for a closer look at this cool technology.

Tags: MS Research, Software Testing

Rating:

Views (62,084)

Comments (20)

Downloads

aL_

thats so awsome Smiley

i like the floating "we catch your bugs" note in the background too Wink

Stebet

This is the coolest thing I've seen in a long time.

For those interested here are the blogs from Nikolai and Peli:
http://blogs.msdn.com/nikolait
http://blog.dotnetwiki.org/default.aspx

I can't wait for this to hit 1.0!

Borum.NET

Nikolai and Peli,

Very interesting technology - looking forward to v1.0 and a 64-bit version. Speaking of 64-bit, when will you release a beta that supports that version of the framework?

ben2004uk

In reply to Borum.NET

#Jul 4th @ 1:32 PM

As far as I am aware, 64bit version isn't planned any time soon. My suggestion - use a 32bit virtual machine.

stevo_

Been using pex a little (not had time to really get into it yet), but its really impressive.. great work on this guys!

Borum.NET

Too bad about the 64-bit version. We're more and more developers running in 64-bit environments (even in development), so it would really really nice to have access to the entire suite of tools. Running in a virtual environment when doing unit testing is probably one possible workaround, but I would definitely welcome 64-bit support.

I've subscribed to the PEX list but haven't seen any trafic yet.

Automated unittesting is worth dying for if done right. Can't really think of any code that wouldn't benefit (I suspect they even used Pex to test Pex Smiley

peli

Good news: we are working on a WOW64 version of Pex (support for exploring 32-bit .net processes on 64-bit).

aL_

ive been playing around a lille with pex now and i just have to say.. WOW :O
its GREAT! it sounded cool in the interview and all but in reality its even more awsome!
if you havent already, you Have to check this out! the vs integration is sweeet Smiley

the last time i had this kind of experience was when i tried out wpf! Smiley

unit testing is no longer a horrible bore but actually something interesting Smiley

again, great work pex team! cant wait for the next release Smiley

i do have a qustion though Smiley

is there a way to get pex to try a generic method with a bunch of diffrent types? i guess i could use like a list of instances of the various types and get pex to use diffrent lists or diffrent indexes in the list (like with a static list and a int argument to the parameterized method)

but im sure there is a smarter way Smiley

peli

Pex actually supports generic unit tests: add generic arguments to the unit test and specify the instanciation types using 'PexUseGenericArgumentsAttribute':

    [PexMethod]
    [PexUseGenericArguments(typeof(int))]
    public void AddItem(List<T> target, T item) {
       ...
    }