Test Driven Development in R
Hi, Jose:
How does the following
I have not studied "Test Driven Development", but I routinely
write documentation "*.Rd" files before I write code, and the
documentation files include test cases in the "\examples" section. With
"\dontshow", I hide tests that I don't think would benefit a user.
The source for the 'fda' package includes numerous constructions
like the following:
\dontshow{stopifnot(}
all.equal(fRegressout, knee.hip.f)
\dontshow{)}
Here, "fRegressout" and "knee.hip.f" are two different objects
that should theoretically be equal. I show the user that they are in
fact equal, but I don't bother the user with the "stopifnot" call that
will stop "R CMD check" to let me know that the code fails this test. I
have not used "Runit", but it's on my "to do" list. "Sciviews-K" sounds
interesting, but I have not used it.
Also, Chambers (2008) Software for Data Analysis (Springer) says
that "trustworthy software" is "The Prime Directive". TDD sounds like
it would support that goal.
I will not be able to attend useR 2009 but would be interested in
a further discussion of this issue.
Best Wishes,
Spencer Graves
Tobias Verbeke wrote:
Jose Quesada wrote:
Hi, I wonder what kind of interest there is on Test Driven Development (TDD) in R. Test Driven Development consists of writing the test before the function, and iteratively build the function until it passes the test. Python and Ruby (specially Ruby) have very strong test-oriented cultures. In fact, in Ruby at least the custom is to do TDD and lately Behavior-driven development (BDD). In BDD, one writes a story of what one would want the code to do. This story is almost native English, and then the test suite converts it into something that the language understand as tests. There are some posts on the list about this, but they are about testing in general (Runit), not TDD. Example: http://thread.gmane.org/gmane.comp.lang.r.general/85047 Recently, I found there is an alpha, but working implementation of TDD for Komodo edit: www.sciviews.org/SciViews-K/index.html The editor has a green bar that becomes red as soon as one edits a function, and that edit breaks the tests. This is tremendously useful. Using Gmane search, the only mention I could find on svUnit was: http://thread.gmane.org/gmane.comp.lang.r.general/136632/focus=136662 I think this could make a great UseR 2009 talk. Ideally, by someone with more R experience than me, and even more ideally by Philippe Grosjean :), but it push comes to shove, I could prepare such a talk. Would this be interesting at all? Are there any resources that I have missed?
There is the RUnit package which is a mature xUnit implementation for R. I don't know of a tight integration into an editor (apart from that it is _planned_ for StatET, the Eclipse R plug-in), but as such it is very useful already. http://cran.r-project.org/web/packages/RUnit/index.html HTH, Tobias
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