Tuesday, 9 December 2014

Reducing Technical Debt with Smart Unit Tests

One of the reasons behind Technical Debt is the lack of appropriate test suites around a certain feature. Especially when implementing something new, tests are critical in shaping a robust and quality solution. Often, if you have something in the works and you are not strictly operating TDD, tests are behind where they should be.

Visual Studio 2015 introduced Smart Unit Tests, which are nothing but the former MSR Pex project, rebranded and productised. What Pex/a Smart Unit Test does is to analyse your code and create a basic suite of unit tests to test the basic, border scenarios. Here is an example:


Right click on the method, Smart Unit Tests


and here is the result:


Of course – this is a really, really basic scenario. What is interesting IMHO is how it is doing it behind the scenes:


as mentioned, it is a full-fledged Unit Test. Very basic, but still a good starting point, saving time while in the works. And if you save it, the Smart Unit Test engine is automatically going to create a new Test Project with the aforementioned tests contained in there. Again, it is not meant to remain as-is (“Sum748” is not a great test name for instance…) but it is still better IMHO than doing everything on my own.

Let’s make things a bit harder now:


That is very crappy code in small scale. No exception management at all, just the plain and down-to-the-bone feature, potentially in development. I can ear people screaming, but it happens extremely often in every organisation. This is the output of Smart Unit Test in this scenario:


It seems I need to spend some time on handling DivideByZeroExceptions and OverflowExceptions, to begin with…

1 comment:

  1. Nice post, Matteo. Would love to hear more about your experiences with Smart Unit Tests.