val message: String? (source)
Usually the error message but an empty string in case of certain test-runners.
The Spek plugin for Intellij as well as running JUnit tests in IntelliJ print this message and printStacktrace in addition which uses localizedMessage which in turn usually calls message, resulting in showing this message twice shortly after each other. This hack combined with the changed behaviour in getLocalizedMessage works around this double error message in reporting by setting the message to an empty string in case of the aforementioned runners.