My GSoC 2018 project (and first package!), lsp-test <https://hackage.haskell.org/package/lsp-test-0.1.0.0>, is now available on Hackage. It allows you to carry out functional end-to-end tests at a high level for LSP <https://microsoft.github.io/language-server-protocol/> servers, and we’re currently using it in haskell-ide-engine <https://github.com/haskell/haskell-ide-engine>. Many thanks to Alan Zimmerman and Zubin Duggal for their invaluable help this summer. Hopefully it will help improve your LSP servers, or maybe entice you to make one for your language!