I'm using JUnit since I started this project and everything works just fine. I have a couple of hundreds tests, and of course, here and there I start them all. Right click on root test folder, run (or debug) with JUnit. But since yesterday, when I do that, the result is:

Process finished with exit code 0

without starting any of tests. Same thing is with any folder in folder tree. I can still run a single test class, but I really need an option to start them all. If any of you have any ideas, please drop them here.

Here is what is logged when I try to run tests:

2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - IntelliJ IDEA 11.1.2  Build #IU-117.418 
2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - JDK: 1.6.0_31 
2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - VM: Java HotSpot(TM) Client VM 
2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - Vendor: Sun Microsystems Inc. 
2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - OS: Windows 7 
2012-10-31 15:16:55,693 [2727217]  ERROR - ij.psi.impl.source.PsiFileImpl - Last Action: RunClass 
2012-10-31 15:16:55,693 [2727217]  ERROR - m.intellij.util.ExecutorsQuery - com.intellij.psi.tree.IFileElementType cannot be cast to com.intellij.psi.tree.IStubFileElementType 
java.lang.ClassCastException: com.intellij.psi.tree.IFileElementType cannot be cast to com.intellij.psi.tree.IStubFileElementType
    at com.intellij.psi.impl.source.PsiFileImpl.calcStubTree(PsiFileImpl.java:976)
    at com.intellij.psi.stubs.StubIndexImpl$1.perform(StubIndexImpl.java:239)
    at com.intellij.psi.stubs.StubIndexImpl$1.perform(StubIndexImpl.java:220)
    at com.intellij.util.indexing.ValueContainer.forEach(ValueContainer.java:60)
    at com.intellij.psi.stubs.StubIndexImpl.process(StubIndexImpl.java:220)
    at com.intellij.psi.stubs.StubIndexImpl.get(StubI
java junit intellij-idea
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