lsp-test should wait for the lsp server to exit cleanly

[pepeiborra]

Even for well-behaved servers, runSession calls cleanupProcess immediately after sending the exit message:
https://github.com/bubba/lsp-test/blob/master/src/Language/Haskell/LSP/Test/Session.hs#L268-L272

This causes problems in the ghcide benchmark suite, where we are unable to collect the RTS statistics before lsp-test kills ghcide, and are forced to manage our own exit protocol. But this in turn causes problems with lsp-test, as reported in https://github.com/digital-asset/ghcide/issues/617

[lukel97]

Hi, can you try out lsp-test on master and see if its waiting for ghcide to exit now?

[pepeiborra]

Thanks for the quick response! I can confirm it works as expected now.

[lukel97]

There's a new bug fix release on Hackage now