Dev test

[msimerson]

• test: switch runner from mocha to node builtin
• test: remove useless done
  • they are only required for callback style async tests
• pkg: rm .travis.yml
• ci: update test runners
• ci: automatically test node LTS versions
• ci: update lint workflow

[msimerson]

Several changes here:

• dep(eslint): restored declaration of dependency on v8
• move the test file into lib (next to the code it runs). Naming files with *.test.js and putting them next to the files they test is apparently a pattern. Your thoughts?
• mocha -> node --test
  • ci: drop testing for older nodes that lack support for node --test
• ci: updated lint workflow

[msimerson]

naming files with *.test.js and putting them next to the files they test is apparently a pattern.

Something I just thought of and don't like, is that putting the test file in lib publishes it on npm. That's a small deal, but with 36m weekly downloads, the smallness has a very large multiplier. I've talked myself out of it. 😲 Sorry for the noise.

Note to self: the NPM docs say that putting a .npmignore in a subdirectory will override [files], so one could echo '*.test.js' > lib/.npmignore. With dozens of npm modules that (still) use the ./test/ convention, I'm not yet convinced.

[whitequark]

Thanks!