Most of my code writing time last week writing was spent in JavaScript land (or ECMAScript, wonder it the most commonly used name will ever change). I was to write a small templating package and had to write some new stuff and set out to use JsTestDriver and after a few minutes I was up and running in Eclipse.

The idea is OK I guess – run tests and production code in the same environment it will run in when deployed. There are a couple of cons to JsTestDriver (used through Eclipse) though:

  1. if you’re configuration file doesn’t include the test file you’re trying to execute, there’s no clue to what you’ve done wrong – the panel in Eclipse will just show the green bar and 0/0 tests run.
  2. if you have syntax (or construct like) errors in your unit under test, you’ll get the same behavior as above
  3. sometimes you’re served a cached version of (some of) the JS source files – hence there’s a button to “refresh browsers” and it’s sad that it has to be there and that you actually have to use it
  4. sometimes the engine gets into some strange state where it dryRuns the tests instead of actually executing them

Apart from that, its behavior is quite predictable. Minor issues:

  1. running a test complete locks Eclipse’s UI thread
  2. a Rerun quick command option would be great (Ctrl+3)


Another minor issue is that the “index” of JsHamcrest matchers is really hard to get an overview of. Whenever I wanted to use a certain type of matcher, it was really hard to quickly tell from the documentation if it was there or not. Go see for yourself and look for a matcher that mathes any object for instance.

# get a list of matchers:
curl "http://jshamcrest.destaquenet.com/modules/matchers.html" | grep "dt id" |cut -d '"' -f 2 |cut -d '.' -f 3


JsMockito works really nice. The only thing that could’ve been better is the integration with JsTestDriver: when a verify step fails, you’ll get a good error message but you don’t get the typical feedback as from which line the verify/assert that failed was on. Not a big deal since you see which test that failed.