I can't run any unit tests

Has anyone seen this? Is it really just me?

When I run any test I see:

java.lang.InstantiationException: com.intellij.rt.execution.junit.IdeaTestRunner
at java.lang.Class.newInstance0(Class.java:335)
at java.lang.Class.newInstance(Class.java:303)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:113)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:40)

And then it quits.

This is http://jetbrains.net/jira/browse/IDEA-8738