ExternalChangelogTest.java:
Extracted constants SERVER_ID_1 and SERVER_ID_2.
Renamed getAttributeValue() to getAttributeValueOrNull().
Extracted new getAttributeValue() from getAttributeValueOrNull(), checkValue() and checkPossibleValues().
In ECLGetEligibleCountTest(), extracted constants to better explicit the code + removed the count local variable + extracted method now()
Removed useless code blocks.

ReplicationServerDomain.java:
In getEligibleCount(), removed a useless if statement.