On test verbosity (A Ruby Rant, but not only)

Testing of Ruby packages is nowadays mostly a recurring joke to the point I didn’t feel I could add much more to my last post — but there is something I can write about, which is not limited to Ruby at all!

Let’s take a step back and see what’s going on. In Ruby you have multiple test harnesses available, although the most commonly used are Test::Unit (which was part of Ruby 1.8 and is available as a gem in 1.9) and RSpec (version 1 before, version 2 now). The two of them have two very different defaults for test output: the former uses, by default, a quiet “progress” style output (one dot per test passed), the latter uses a verbose “documentation” style. But both of them can use the other style as well.

Now, we used to just run tests through rake, using the Rakefile coming with the gem, or the tarball, or the git snapshot, to run tests and build documentation, since both harnesses have very tight integrations with it — but since the introduction of Bundler, this starts to get more troublesome than just writing the test commands out in the ebuild explicitly.

Today I went to bump a package (origin, required for the new Mongoid), and since I didn’t wire in the tests last time (I was waiting for a last minute fix), I decided to do so this time. It should be of note that while, when using rake to run the tests, you’re almost entirely left to the upstream’s preference on what style to use for the tests, it’s tremendously easy to override that in the ebuild itself.

The obvious question is then “which of the two styles should ebuild use for packaged gems?” — The answer is a bit complex, which is why this post came up. Please also note that this does not only apply to Ruby packages, it should be considered for all packages where the tests can be silent or verbose.

On a default usage, you only care about whether the tests fail or pass — if they fail, they’ll give you as much detail as you need, most of the times at least, so the quiet (progress) style is a very good choice: it’s less output, which means smaller logs, less context, and it’s a win-win. For the tinderbox, though, I found out that having more verbose output is useful: to make sure that other tests are not being skipped, to make sure that the build does not get stuck, and if it does, where it got stuck.

Reconciling these two requirements is actually easier than one might think at first because it’s an already solved problem: both perl.eclass and, lately, cmake-utils.eclass support one variable, TEST_VERBOSE which can be set to make the tests output more details while running. So right now origin is the first Ruby ebuild supporting that variable, but talking about this with Hans we came to the conclusion we need a wrapper to take care of that.

So what I’m working on right now is a few changes to the Ruby eclasses so that we support TEST_VERBOSE and NOCOLOR (while the new analysis actually strips out most of the escape codes it’s easier if it doesn’t have to do that!) with something such as ruby-ng-rspec call (which can also check whether rspec is properly in the dependencies!). Furthermore I plan on changing ruby-fakegem.eclass so that it also allows to switch between the current default test function (which uses rake), one that uses RSpec (adding the dependency!), and one that uses Test::Unit. Possibly, after this, we might want to do the same thing with the API documentation building, although that might be trickier — in general though having the same style of API docs installed, instead of using each project’s own, might be a good idea.

So if your package runs tests, please try supporting TEST_VERBOSE, and if it can optionally use colors, make sure it supports NOCOLOR as well, thanks!

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