How to load gems only when your tests are not run from TextMate

Working with new people often influences the way you work. The influences can range from picking up simple tricks to seeing fundamental facts about your craft in a new light.This week when I began working with James I saw him run his tests directly from TextMate. Of course I knew it was possible to run Ruby from TM, including tests.For some inexplicable reason however I had never bothered to try it. This trick is very convenient for two reasons: TextMate cleans up the backtraces and resolves each level of the trace to a clickable link to your code file. So I decided to include this trick in my workflow.I encountered two problems with this however. Two gems I usually use in my tests don’t play well with running tests from TextMate.


The redgreen gem highlights the . F and E (among other bits) in your test runs with green, red and yellow. When running my whole test suite it’s something I want to have. It’s not only visually pleasing, but it also lets me see at a glance whether any problems were encountered.When run from TextMate, tests using redgreen are displayed without having the console coloring stripped out, which gives something like this:

The result of running tests from TextMate, when using redgreen

Riiiight.For the record, here’s the nice result when run at the console:

Running tests with redgreen, from the console


The other gem I can’t do without is James Golick and Dan Croak’s quietbacktrace. This gem lets you specify filters and silencers to clean up those huuuuuge Rails or Merb backtraces.Filters let you remove useless parts of a given line in the backtrace, such as the path leading to your gems. Silencers let you completely remove some lines from the backtrace, such as all the lines referring to what happened inside Rails, leading to your error. The most popular filters and silencers are already provided with quietbacktrace, as you’ll see below.So the result, of course is that messing with backtraces breaks TextMate’s ability to link a backtrace line with the corresponding file.

A simple snippet to fix this

Since I didn’t really want to do away with these tools, I included a bit of a hacky snippet in my test_helper.rb file to detect whether a test run was happening in TextMate or at the console.If you find yourself in the same fix as me, feel free to use the following.Among your requires:

unless IN_TM
  require 'redgreen'
  require 'quietbacktrace'end

And then:

class Test::Unit::TestCase
  unless IN_TM
    self.backtrace_silencers << :rails_vendor
    self.backtrace_filters   << :rails_root

Now I can have my testing niceties when running my tests from the console and they don’t break the TextMate integration :-)

Trying this out for the first time?

If like me you just decided to try this out for the first time, the shortcuts are easy to remember. Command-R runs any Ruby file (in this case, the whole test file) and Command-Shift-R runs the single test the cursor is in.There’s a little hiccup in sight, however. If you’re using Rails 2+, you have to apply a very small fix to TextMate before you’ll be able to run your tests. Read more about the fix on Marc-André Cournoyer’s blog.