Test Coverage and testing angles

My blog has moved. You can view this post at the following address: http://www.osherove.com/blog/2005/4/3/test-coverage-and-testing-angles.html
Published Sunday, April 03, 2005 12:54 PM by RoyOsherove
Filed under: ,

Comments

Sunday, April 03, 2005 8:35 AM by Nauman Leghari

# re: Test Coverage and testing angles

A really good observation. I just realized that this technique can be very effectively used in unit testing existing code. Which is difficult in normal circumstances.
So,

a) comment out existing functionality that we want to check before writing any test. b) Then write tests
c) Uncomment only the lines which are affected by the previously written test.

Any comments?
Sunday, April 03, 2005 9:42 AM by Roy Osherove

# re: Test Coverage and testing angles

Nauman:
It might be possible, some of the time. But sometimes testing existing code means testing a whole bunch of code together (no simple way about it). I don't see myself commenting out 50 lines of code just so a test will fail.
I'd personally only use this if I have specific tests, not generic ones.
Monday, April 04, 2005 6:39 AM by Paul Bartlett

# Re: Test Coverage and testing angles

I believe there are actually tools that make these sort of modifications automatically to the executables, but I can't recall off hand whether they are for Java or .NET (i.e. modify bytecode or IL). If I manage to nudge my memory sufficiently I'll post another comment...
Monday, April 04, 2005 11:05 AM by Paul Bartlett

# re: Test Coverage and testing angles

The approach is called "mutation testing", and there are some tools available (http://www.xpdeveloper.com/xpdwiki/Wiki.jsp?page=MutationTestingTools) but unfortunately none I've seen for the .NET environment.
Monday, April 04, 2005 11:17 AM by Paul Bartlett

# re: Test Coverage and testing angles

Wrong again! Peli has written about it (http://blog.dotnetwiki.org/archive/2004/05/22/255.aspx) and mentions nester (http://nester.sf.net) which I think I missed in the list I linked to in my previous comment...
Monday, April 04, 2005 3:34 PM by TrackBack

# OdeToCode Links For April 4

Monday, April 04, 2005 11:04 PM by TrackBack

# New Team System Stuff - 2005-04-05

Visual Studio Team System

Today, we have a double-header of Team System webcasts:

9:00 AM PDT –...