[CASSANDRA-16595] Remove test parallelism from ant build.xml in all branches

• Type: Task
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.2.20, 3.0.25, 3.11.11, 4.0-rc1, 4.0
• Component/s: Test/unit
• Change Category: Operability
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/1185593907ba6597c29da1dfb5e6edb121b358c5 https://github.com/apache/cassandra/commit/c52f50f046fd1a8e1c7f17d9a1952e2bd92aeb4c

Test and Documentation Plan

CI

• Assignee: Michael Semb Wever
• Reporter: Michael Semb Wever

Authors

Michael Semb Wever

Reviewers

Berenguer Blasi, David Capwell, Yifan Cai

• Created: 13/Apr/21 08:53
• Updated: 18/Jun/23 20:19
• Resolved: 15/Apr/21 22:48

Description

Cassandra's build.xml supports parallel test runners. This functionality is available through `-Dtest.runners` and the `testparallel` ant macro.

Having not been actively used and atrophied over time, it breaks a number of tests. The distributed in-jvm tests don't work at all with parallel runners (currently they need `-Dtest.runners=1` specified to work). And there are plenty of flakies, from where
tests use fixed ports (StorageServiceServerTest), to byteman (eg BMUnitRunner), and around conf files on disk.

This was raised on the dev ML, where the consensus was to remove it: https://lists.apache.org/thread.html/r1ca3c72b90fa6c57c1cb7dcd02a44221dcca991fe7392abd8c29fe95%40%3Cdev.cassandra.apache.org%3E

The idea is to then replace ant test parallelism with docker container parallelism.

Issue Links

• fixes: CASSANDRA-13191 test failure in org.apache.cassandra.hints.HintsBufferPoolTest.testBackpressure
• fixes: CASSANDRA-16569 Flaky StorageServiceServerTest
• fixes: CASSANDRA-16587 flaky AntiCompactionBytemanTest.testRedundantTransitions byteman Connection refused
• is duplicated by: CASSANDRA-16566 Fix test testIsrepairedArg - org.apache.cassandra.tools.SSTableRepairedAtSetterTest
• relates to: CASSANDRA-7442 Parallelize unit test runner
• relates to: CASSANDRA-16604 Parallelise docker container runs for tests in ci-cassandra.a.o