testRegularMessageSending is a kind of smoke test for the stack used in OverlappingMergeTest:

• three channels a,b,c are created with a particular stack (see modifyConfigs)
• each of a,b,c sends 5 multicast messages to the group, with message payloads "1", "2", "3", "4", "5"
• the receiver in each channel collects up the multicasts received
• the test checks that all 15 messages are received by each of the channels, and an assertion error is thrown is this is not the case

This test is failing occasionally. An example of the error:

Error Message
(C) num_mcasts=C: 1 C: 2 C: 3 C: 4 C: 5 A: 1 B: 1 A: 2 B: 2 B: 3 B: 4 A: 4 B: 5 A: 5  expected: 15)
Stacktrace
java.lang.AssertionError 
at org.jgroups.tests.OverlappingMergeTest.checkReceivedMessages(OverlappingMergeTest.java:476) 
at org.jgroups.tests.OverlappingMergeTest.testRegularMessageSending(OverlappingMergeTest.java:66) 

This assertion error indicates that multicast #3 was not received from A by C.

This is a very simple scenario and failures should not be occurring. I mention this error as there are other merge tests, namely:

• testOverlappingMergeWithBC
• testOverlappingMergeWithABC
  which are more complex, but when we look at their failures, they fail on an initial step similar to the one described above.