lsp-test

lsp-test is a functional testing framework for Language Server Protocol servers.

import Language.Haskell.LSP.Test
main = runSession "hie" fullCaps "proj/dir" $ do
  doc <- openDoc "Foo.hs" "haskell"
  skipMany anyNotification
  symbols <- getDocumentSymbols doc

Examples

Unit tests with HSpec

describe "diagnostics" $
  it "report errors" $ runSession "hie" fullCaps "test/data" $ do
    openDoc "Error.hs" "haskell"
    [diag] <- waitForDiagnosticsSource "ghcmod"
    liftIO $ do
      diag ^. severity `shouldBe` Just DsError
      diag ^. source `shouldBe` Just "ghcmod"

Replaying captured session

replaySession "hie" "test/data/renamePass"

Parsing with combinators

skipManyTill loggingNotification publishDiagnosticsNotification
count 4 (message :: Session ApplyWorkspaceEditRequest)
anyRequest <|> anyResponse

Try out the example tests in the example directory with cabal test. For more examples check the Wiki

Developing

The tests are integration tests, so make sure you have the following language servers installed and on your PATH:

haskell-ide-engine

• Check out a relatively recent version of the repo, or see .travis.yml to get the exact commit used for CI.
• stack install

javascript-typescript-langserver

npm i -g javascript-typescript-langserver

Then run the tests with cabal test or stack test.

Troubleshooting

Seeing funny stuff when running lsp-test via stack? If your server is built upon Haskell tooling, keep in mind that stack sets some environment variables related to GHC, and you may want to unset them.