Debugging the Undebuggable

I bumped up against an interesting problem today. I was trying to write a unit test for our CRM code (I’ll write about my endeavor in a another post).

Anyway, I was trying to test a method (a WebMethod, actually) that was inside a class, which was inside an asmx file. Strangely enough, I never did that before, and was ready to conquer another framework with Isolator.

I was just looking to add a reference to the site from my test project. But that did not work – apparently you can’t add a reference to a site project. The next surprise (to me. Those doing it everyday, probably have figured this out eons ago) is that when you build a site, you don’t get a ready-made bin directory where I expected it would be. 

It did not dissuade me. I took my trusty Reflector with me and found out that there is a bin directory under the PrecompiledWeb folder, and an assembly called App_Code.dll contains my class. I added the reference in my test project directly to this assembly. Then I went on to write a test.

Expectedly, my test failed a couple of times (I was using the Act-Assert-Arrange method for writing tests). I looked at the code, added some Isolate.Fake.StaticMethods<>, and then when it insisted to fail, I decided to debug. Immediately I figured that I couldn’t step into the class. I looked for PDB files, but couldn’t find them (probably looking in the wrong places). I tried putting a Debugger.Break command in my class, but that did not work either (probably due to some caching or something. As you’ve figured out by now, I was not really in a research mode).

So how can I debug this class, without breaking a sweat?

I took the class file (myclass.asmx.cs) and added a link to it in my test project. Presto. Now the class-under-test is in the test project. I added a couple of missing references, and the class was now debug-able. The test was completed a few minutes later.

We always talk about easy unit testing. And it is easy when you know how, including when you have this kind of ammo in your bag of tricks. When you learn a trick – teach others – they deserve to know as well!

What’s the coolest way that you found to go around a testing problem?

Gil Zilberfeld

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