Resetting the master before stopping the slave was generating the message
"[ERROR] Slave I/O: Got fatal error 1236 from master when reading data from
binary log: 'could not find next log', Error_code: 1236". In consequence,
the test case was failing because the message had not been suppressed.
To circumvent the failure, we rewrote the test stopping the slave before
resetting the master. We prefer this alternative rather than suppressing
the message.
The issue appears when number of heartbeat events non-zero before start of test
block. But really we need to check that no new events has received during test block.
So I did following:
1. Replace absolute values by diff of values
2. Increase heartbeat period from 1.5 to 5 sec