The test EventGroupTestCase.testCompareTo() fails intermittently because it depends on the fact that some time passes between the creation of one object and the next.
This is the affected code:
In order for the assertions to pass, there must be at least one nanosecond between the creation of g1 and g2. Sometimes this is not the case so the test fails. I suggest inserting a Thread.yield() call in the middle of the two cretions, like this: