JRuby test explorations

[headius]

Here's some notes from the RubyConf hack session for net-imap on JRuby.

• There's one test currently that hangs the suite: test_starttls_unknown_ca from test_imap.rb. I have not investigated but it hangs with a single thread at 100% apparently doing an SSL socket read over and over.
• assert_local_raise has issues on JRuby similar to those found in TruffleRuby, where setting the backtrace to nil does not cause it to get repopulated by a subsequent raise. Stubbing out the assertion dropped total F+E from 100 to 85.
• The Data classes defined in command_data.rb appear to be losing state. This is probably a continuation of bugs with the specialization of Data to use real fields in JRuby. Subclasses aren't inheriting that field metadata properly so the state is lost.

[nevans]

Sorry, I didn't merge the Data polyfill for the v0.6.6. I'd intended to make that release before doing anything else at RubyConf, but the incompatible changes to simplecov v1.0.0 broke the build and pushed back the release until yesterday. 🤞🏻 Hopefully we'll have JRuby passing in CI for the next release (even if that means we need to pend/omit a few tests).