fixing hang in alpine linux and adding test

[ryhinchey]

This PR fixes issue #81. The work was mostly done here but got reverted at some point. I also added a test for ash.

I tested this in an alpine linux docker container locally as well.

[ryhinchey]

The Travis build is failing with the message error Your lockfile needs to be updated, but yarn was run with --frozen-lockfile. I didn't change any dependencies but when I run yarn locally, I see this addition to yarn.lock:

prettier@^1.19.1:
  version "1.19.1"
  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.19.1.tgz#f7d7f5ff8a9cd872a7be4ca142095956a60797cb"
  integrity sha512-s7PoyDv/II1ObgQunCbB9PdLmUcBZcnWOcxDh7O0N/UwDEsHyqkW+Qh28jW+mVuCdx7gLB0BotYI1Y6uI9iyew==

Happy to commit - just let me know.

[tabrindle]

Sure, go ahead and fix that. Everything else looks good, thanks!