Parallel test runner

[kellyredding]

Make it happen!

Consider:

• https://github.com/grosser/parallel
• https://github.com/seattlerb/minitest/commit/bdbf38df3475dcc8ddd6d11ebede48cdd5f55008#L2R1

[kellyredding]

Also, need to make captured io be thread safe: https://github.com/seattlerb/minitest/commit/f9f14b50966da21116ff4b4f8a43b6fd95a72f02

[kellyredding]

Some updated thoughts on this:

• stubbing singletons and database tests are problematic for parallel tests
• can get around some of this if you run in sep processes
• but to do that you have to deal with
  • sep db for each process
  • aggregate results for each process
  • how to split up tests across processes

So, some ideas on getting around that:

• run all db tests in a transaction
• run all tests by "#{file_path}:#{line_num}", allow to be read in on $stdin
• give CLI a "machine output" mode where results are dumped to $stdout in decode-able manner
• have main test run process split tests and fire up N sub processes with file/line_num input, gather machine output, and display results.

Anyway, not sure when/if we get to this, but notes none-the-less

[kellyredding]

(notes to self)

Had some more thoughts on this:

• have new gem that allows parallel running
• provides a custom runner/view (?)
• brings in sqlite as a dependency
• stores test data in db
• forks processes to run tests
• test data updated by the processes in the db
• hopefully processes show "live" results via writing to a shared IO stream
• view queries db to output test results

Basically I wanna use a sqlite as a nice, ACID-compliant, way to have multiple processes write shared result test data. I don't want to bring in sqlite as a dependency to assert as it's only needed if you even want to run tests parallel.

Would probably need to refactor the runner and view to have a more extendable API to allow this new gem to customize as needed.

Anyway, moar thoughts on this matter.

[kellyredding]

https://github.com/redding/parassert

• use sqlite
• use parallel
• see how that goes to start