Method setUp in android.test.AndroidTestCase not mocked

I'm trying to come with terms with the new unit test feature of Android Studio. I've followed the instructions on http://ift.tt/1KkPIk8. The description there explicitly mentions the 'Method ... not mocked' error and suggests to put the following into the build.gradle:

android {
  // ...
  testOptions { 
    unitTests.returnDefaultValues = true
  }
}

This works in so far as the tests run when started from the command line with

gradlew test --continue

but not when I run the test class from Android Studio with rightclick -> run. This way, I get the same error again:

java.lang.RuntimeException: Method setUp in android.test.AndroidTestCase not mocked. See http://ift.tt/1zlzRtn for details.
    at android.test.AndroidTestCase.setUp(AndroidTestCase.java)
    at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:86)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

Any ideas on how to solve this?