[wp-trac] [WordPress Trac] #52548: Run Multisite tests in parallel during CI

[WordPress Trac]

#52548: Run Multisite tests in parallel during CI
------------------------------+-----------------------------
 Reporter:  johnbillion       |      Owner:  (none)
     Type:  task (blessed)    |     Status:  new
 Priority:  normal            |  Milestone:  Awaiting Review
Component:  Build/Test Tools  |    Version:
 Severity:  normal            |   Keywords:
  Focuses:                    |
------------------------------+-----------------------------
 Related: #50401

 The PHPUnit test workflow takes around 26 minutes (±2 minutes) to run on
 GitHub Actions. Each job within each run runs the whole test suite, with a
 total of 8 jobs (7 distinct PHP versions plus an extra job for 7.4 with
 memcached).

 We should take more advantage of GitHub Actions' parallel processing of
 jobs within a workflow. If we reduce the times for each job by spreading
 their work across multiple jobs and all jobs still run in parallel, we
 reduce the overall workflow time as long as the time saving is greater
 than the time taken to set up each job (download the artefact, install
 dependencies, and start the containers).

 One way to do this is by splitting the Multisite tests into their own jobs
 and adding a multisite flag to the matrix. This very roughly halves the
 time for the actual PHPUnit tests in each job, and in practice reduces the
 total duration of the workflow from ~26 minutes to ~16 minutes.

 == Items to consider before this can be implemented:

 * How to correctly report the results to the WordPress.org host test
 results collector

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/52548>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform