Test passes although it fails unexpectedly

I have an erronous test class that cannot be loaded in the container due to a NoClassDefFoundError. (A dependent class is missing.)
The test passes unexpectedly and all test methods are reported to have passed although log entries or SystemOuts show that the methods are actually never invoked.

The problem seems to be a regression that came with the last release.
In JUnitTestRunner the TestResults exception is overwritten with null in such a case.
I will attach a screenshot of the debugger showing that.
I also have a try of a patch that I will link as soon as I prepared the pull request on github.