Groovy Test will not run in plugin versions higher than 2.0.0

We have a particularly long test with many static String variables initialized at the start of the test and then many test methods which uses these. When updating to newer versions from the old 2.0.0 version of the Groovy plugin, the test was no longer able to be run. The message we get is "JUnit Tests not found". Other groovy tests work just fine. Also, pulling methods out from the test into a shorter file works. It is only when we leave the lengthy test as is that it fails to run. This is not a problem with the older version of the plugin, so we guess something must have changed. I am attaching the test in question.