Impossible to tell what line cause test failure

This is a bug in junit-interface (https://github.com/sbt/junit-interface/issues/41). However, I'm going to file it here as well because I think it's a serious enough that we should probably be involved in fixing it

Our test set is becoming a nightmare to run. Whenever a test fails the output looks like this:

    [error] Test com.benmccann.StringUtilTest.myTest failed: null
    [info] com.benmccann.StringUtilTest
    [info] x myTest

It's really hard to figure out where the error is because there's no line number. All we know is that there way a failure somewhere in a given method, but that's most often a frustrating lack of information.