From 2a72c8669e872c24bd7c3cd43ec43df9d5a5f6be Mon Sep 17 00:00:00 2001
From: Tom McLaughlin <tom@codedown.io>
Date: Fri, 9 Jan 2026 19:38:47 -0800
Subject: [PATCH 1/5] Working on moving LSP test code out to lsp-test-helpers
 noci

---
 tests/app/Spec/Tests/Bash.hs                |   2 +-
 tests/app/Spec/Tests/Clojure.hs             |   2 +-
 tests/app/Spec/Tests/Cpp.hs                 |   2 +-
 tests/app/Spec/Tests/Go.hs                  |   2 +-
 tests/app/Spec/Tests/Haskell/Diagnostics.hs |  12 +-
 tests/app/Spec/Tests/Haskell/Statements.hs  |   4 +-
 tests/app/Spec/Tests/Julia.hs               |   2 +-
 tests/app/Spec/Tests/Julia/Diagnostics.hs   |   8 +-
 tests/app/Spec/Tests/Python.hs              |  14 +-
 tests/app/Spec/Tests/Ruby.hs                |   2 +-
 tests/app/Spec/Tests/Rust/Diagnostics.hs    |  18 +-
 tests/app/Spec/Tests/Spellchecker.hs        |  10 +-
 tests/app/Spec/Tests/Typst.hs               |   2 +-
 tests/src/TestLib/LSP.hs                    | 277 +++++---------------
 tests/stack.yaml                            |   5 +
 15 files changed, 103 insertions(+), 259 deletions(-)

diff --git a/tests/app/Spec/Tests/Bash.hs b/tests/app/Spec/Tests/Bash.hs
index 5de80c4d..9b347d25 100644
--- a/tests/app/Spec/Tests/Bash.hs
+++ b/tests/app/Spec/Tests/Bash.hs
@@ -37,7 +37,7 @@ tests = describe "Bash" $ introduceNixEnvironment [kernelSpec] [] "Bash" $ intro
   --                                            |] $ \diagnostics -> do
   --   assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "bash-language-server" "test.sh" Nothing [__i|FOO=42|] $ \diagnostics -> do
+  testDiagnostics "bash-language-server" "test.sh" [__i|FOO=42|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics [
       (Range (Position 0 0) (Position 0 3), Just (InR "SC2034"))
       ]
diff --git a/tests/app/Spec/Tests/Clojure.hs b/tests/app/Spec/Tests/Clojure.hs
index 30105ebc..1a027d2b 100644
--- a/tests/app/Spec/Tests/Clojure.hs
+++ b/tests/app/Spec/Tests/Clojure.hs
@@ -31,7 +31,7 @@ tests = describe "Clojure" $ introduceNixEnvironment [kernelSpec] [] "Clojure" $
 
   testKernelStdout "clojure" [__i|(println "hi")|] "hi\n"
 
-  testDiagnostics "clojure-lsp" "test.clj" Nothing [__i|(foo 42)|] $ \diagnostics -> do
+  testDiagnostics "clojure-lsp" "test.clj" [__i|(foo 42)|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics [(Range (Position 0 1) (Position 0 4), Just (InR "unresolved-symbol"))]
 
 
diff --git a/tests/app/Spec/Tests/Cpp.hs b/tests/app/Spec/Tests/Cpp.hs
index 6d6022bc..1120d69f 100644
--- a/tests/app/Spec/Tests/Cpp.hs
+++ b/tests/app/Spec/Tests/Cpp.hs
@@ -40,7 +40,7 @@ tests' flavor = describe [i|C++ (#{flavor})|] $ introduceNixEnvironment [kernelS
 testsWithLsp :: Text -> LanguageSpec
 testsWithLsp flavor = describe [i|C++ (#{flavor}) with LSP|] $ introduceNixEnvironment [kernelSpecWithLsp flavor] [] "C++" $ do
   describe "LSP" $ do
-    testDiagnostics'' "simple" lsName "test.cpp" (Just "cpp")
+    testDiagnostics'' "simple" lsName "test.cpp"
       [__i|int main() {
              undefined_function();
              return 0;
diff --git a/tests/app/Spec/Tests/Go.hs b/tests/app/Spec/Tests/Go.hs
index da4554c6..521b86d7 100644
--- a/tests/app/Spec/Tests/Go.hs
+++ b/tests/app/Spec/Tests/Go.hs
@@ -33,7 +33,7 @@ tests = describe "Go" $ introduceNixEnvironment [kernelSpec] [] "Go" $ introduce
   testKernelStdout "go" [__i|import("fmt")
                              fmt.Println("hi")|] "hi\n"
 
-  testDiagnosticsLabel "gopls: Undeclared name" "gopls" "test.go" Nothing printUnknownCode $ \diagnostics ->
+  testDiagnosticsLabel "gopls: Undeclared name" "gopls" "test.go" printUnknownCode $ \diagnostics ->
     assertDiagnosticRanges diagnostics [(Range (Position 3 12) (Position 3 15), Just (InR "UndeclaredName"))]
 
 printUnknownCode :: Text
diff --git a/tests/app/Spec/Tests/Haskell/Diagnostics.hs b/tests/app/Spec/Tests/Haskell/Diagnostics.hs
index 6b218442..26619d52 100644
--- a/tests/app/Spec/Tests/Haskell/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Haskell/Diagnostics.hs
@@ -27,18 +27,18 @@ import TestLib.Types
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> Text -> SpecFree context m ()
 tests ghcPackage lsName = describe "Diagnostics" $ do
   describe "Foo.hs" $ do
-    testDiagnosticsLabelDesired "Out of scope variable" lsName "Foo.hs" Nothing
+    testDiagnosticsLabelDesired "Out of scope variable" lsName "Foo.hs"
       [__i|module Foo where
            foo = bar
           |]
       ((== [(Range (Position 1 6) (Position 1 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabelDesired "Eta reduce" lsName "Foo.hs" Nothing etaExpandCode
+      testDiagnosticsLabelDesired "Eta reduce" lsName "Foo.hs" etaExpandCode
         ((== [(Range (Position 6 0) (Position 6 14), Just (InR "refact:Eta reduce"))]) . getDiagnosticRanges)
 
   describe "main.ipynb" $ do
-    testDiagnosticsLabelDesired "Top-level putStrLn" lsName "main.ipynb" Nothing
+    testDiagnosticsLabelDesired "Top-level putStrLn" lsName "main.ipynb"
       [__i|-- A comment
            foo = bar
 
@@ -46,7 +46,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
           |]
       ((== [(Range (Position 1 6) (Position 1 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
-    testDiagnosticsLabel "Top-level putStrLn with diagnostic" lsName "main.ipynb" Nothing
+    testDiagnosticsLabel "Top-level putStrLn with diagnostic" lsName "main.ipynb"
       [__i|-- Some comment
            import Data.ByteString.Lazy.Char8 as BL
            foo = bar
@@ -56,7 +56,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
         [(Range (Position 4 0) (Position 4 8), x)] | containsAll x ["Ambiguous occurrence", "putStrLn"] -> return ()
         xs -> expectationFailure [i|Unexpected diagnostics: #{xs}|]
 
-    testDiagnosticsLabelDesired "Reordering" lsName "main.ipynb" Nothing
+    testDiagnosticsLabelDesired "Reordering" lsName "main.ipynb"
       [__i|import Data.Aeson.TH
            {-\# LANGUAGE TemplateHaskell \#-}
            foo = bar -- This should be the only diagnostic we get
@@ -64,7 +64,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
            $(deriveJSON defaultOptions ''Foo)|]
       ((== [(Range (Position 2 6) (Position 2 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
-    testDiagnosticsLabelDesired "Complicated reordering" lsName "main.ipynb" Nothing
+    testDiagnosticsLabelDesired "Complicated reordering" lsName "main.ipynb"
       [__i|import Data.Aeson as A
            import Data.Aeson.TH
            :set -XTemplateHaskell
diff --git a/tests/app/Spec/Tests/Haskell/Statements.hs b/tests/app/Spec/Tests/Haskell/Statements.hs
index 3f11f6e1..c75522e2 100644
--- a/tests/app/Spec/Tests/Haskell/Statements.hs
+++ b/tests/app/Spec/Tests/Haskell/Statements.hs
@@ -22,7 +22,7 @@ tests ghcPackage = describe "Statements" $ do
       timeout 120_000_000 (getHighlights ident (Position 0 1)) >>= (`shouldBe` (Just documentHighlightResults))
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabel "Empty diagnostics" lsName "main.ipynb" Nothing statementsCode $ \diagnostics -> do
+      testDiagnosticsLabel "Empty diagnostics" lsName "main.ipynb" statementsCode $ \diagnostics -> do
         -- Note: normally the server wouldn't send empty diagnostics. But the statement inserts "= unsafePerformIO $ ",
         -- which causes it to emit a "redundant bracket" diagnostic, which then gets filtered out by untransformPosition
         diagnostics `shouldBe` []
@@ -33,7 +33,7 @@ tests ghcPackage = describe "Statements" $ do
       timeout 120_000_000 (getHighlights ident (Position 0 1)) >>= (`shouldBe` (Just documentHighlightResults))
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabel "Redundant bracket" lsName "main.ipynb" Nothing statementsCodeMultiline $ \diagnostics -> do
+      testDiagnosticsLabel "Redundant bracket" lsName "main.ipynb" statementsCodeMultiline $ \diagnostics -> do
         info [i|Got diagnostics: #{diagnostics}|]
         assertDiagnosticRanges diagnostics [(Range (Position 1 9) (Position 1 14), Just (InR "refact:Redundant bracket"))]
 
diff --git a/tests/app/Spec/Tests/Julia.hs b/tests/app/Spec/Tests/Julia.hs
index c44a4640..a5b780c0 100644
--- a/tests/app/Spec/Tests/Julia.hs
+++ b/tests/app/Spec/Tests/Julia.hs
@@ -45,7 +45,7 @@ juliaTests juliaPackage = describe [i|Julia (#{juliaPackage})|] $ introduceNixEn
   describe "LSP" $ do
     Diagnostics.tests lsName
 
-    itHasHoverSatisfying lsName "test.jl" (Just "julia") [__i|print("hi")|] (Position 0 2) $ \hover -> do
+    itHasHoverSatisfying lsName "test.jl" [__i|print("hi")|] (Position 0 2) $ \hover -> do
       let InL (MarkupContent MarkupKind_Markdown text) = hover ^. contents
       text `textShouldContain` "Write to `io` (or to the default output stream"
 
diff --git a/tests/app/Spec/Tests/Julia/Diagnostics.hs b/tests/app/Spec/Tests/Julia/Diagnostics.hs
index 1a91775c..60410eb8 100644
--- a/tests/app/Spec/Tests/Julia/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Julia/Diagnostics.hs
@@ -13,10 +13,10 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> SpecFree context m ()
 tests lsName = describe "Diagnostics" $ do
-  testDiagnostics'' "flags a simple missing reference" lsName "test.jl" (Just "julia") [i|printlnzzzz("HI")|] [] $ \diagnostics -> do
+  testDiagnostics'' "flags a simple missing reference" lsName "test.jl" [i|printlnzzzz("HI")|] [] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [(Range (Position 0 0) (Position 0 11), Nothing, "Missing reference: printlnzzzz")]
 
-  testDiagnosticsLabelDesired "finds symbols from JSON3 package" lsName "test.jl" (Just "julia")
+  testDiagnosticsLabelDesired "finds symbols from JSON3 package" lsName "test.jl"
     [__i|using JSON3: write
          tup = (:car,"Mercedes","S500",5,250.1)
          write(tup)
@@ -24,7 +24,7 @@ tests lsName = describe "Diagnostics" $ do
          |]
     ((== [(Range (Position 3 0) (Position 3 11), Nothing, "Missing reference: printlnzzzz")]) . getDiagnosticRanges')
 
-  testDiagnosticsLabelDesired "finds symbols from Roots package" lsName "test.jl" (Just "julia")
+  testDiagnosticsLabelDesired "finds symbols from Roots package" lsName "test.jl"
     [__i|using Roots: Bisection, find_zero
          f(x) = exp(x) - x^4
          find_zero(f, (8, 9), Bisection())
@@ -34,7 +34,7 @@ tests lsName = describe "Diagnostics" $ do
 
   -- This test is tricky because symbols like "plot" actually come from RecipesBase (or something), so
   -- it checks we're indexing such a transitive dependency.
-  testDiagnosticsLabelDesired "finds symbols from Plots package" lsName "test.jl" (Just "julia")
+  testDiagnosticsLabelDesired "finds symbols from Plots package" lsName "test.jl"
     [__i|using Plots: plot, plot!
          xx = range(0, 10, length=100)
          y = sin.(xx)
diff --git a/tests/app/Spec/Tests/Python.hs b/tests/app/Spec/Tests/Python.hs
index d8a7f8e9..66345543 100644
--- a/tests/app/Spec/Tests/Python.hs
+++ b/tests/app/Spec/Tests/Python.hs
@@ -35,17 +35,17 @@ tests' (kernelName, pythonPackage) = introduceNixEnvironment [kernelSpec kernelN
   testKernelStdout "python3" [i|print(42)|] "42\n"
   testKernelStdout' "python3" [i|import scipy|] Nothing
 
-  testDiagnostics "python-lsp-server" "test.py" Nothing [i|\n\n\nfoo = 42|] $ \diagnostics -> do
+  testDiagnostics "python-lsp-server" "test.py" [i|\n\n\nfoo = 42|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "pylint" "test.py" Nothing [i|\n\n\nfoo = 42|] $ \diagnostics -> do
+  testDiagnostics "pylint" "test.py" [i|\n\n\nfoo = 42|] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [
       (Range (Position 3 0) (Position 3 0), Nothing, "Final newline missing (C0304:missing-final-newline)")
       , (Range (Position 0 0) (Position 0 0), Nothing, "Missing module docstring (C0114:missing-module-docstring)")
       , (Range (Position 3 0) (Position 3 0), Nothing, "Disallowed name \"foo\" (C0104:disallowed-name)")
       ]
 
-  testDiagnostics "pyright" "test.py" Nothing [__i|\# pyright: strict
+  testDiagnostics "pyright" "test.py" [__i|\# pyright: strict
                                                    def f(x: int, y: str) -> None:
                                                      z = 1.0
                                                    f("asdf", 42)
@@ -61,10 +61,10 @@ tests' (kernelName, pythonPackage) = introduceNixEnvironment [kernelSpec kernelN
       , (Range (Position 2 2) (Position 2 3), Just (InR "reportUnusedVariable"), "Variable \"z\" is not accessed")
       ]
 
-  testDiagnostics "pycodestyle" "test.py" Nothing [__i|def f(x: int, y: str) -> None:
-                                                         z = 1.0
-                                                       f("asdf", 42)
-                                                      |] $ \diagnostics -> do
+  testDiagnostics "pycodestyle" "test.py" [__i|def f(x: int, y: str) -> None:
+                                                 z = 1.0
+                                               f("asdf", 42)
+                                              |] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
 
diff --git a/tests/app/Spec/Tests/Ruby.hs b/tests/app/Spec/Tests/Ruby.hs
index 407c5bec..af5f57f1 100644
--- a/tests/app/Spec/Tests/Ruby.hs
+++ b/tests/app/Spec/Tests/Ruby.hs
@@ -49,7 +49,7 @@ kernelTests rubyPackage = do
             info [i|RUBY_VERSION result: #{t}|]
             t `textShouldContain` versionString
 
-    itHasHoverSatisfying "solargraph" "test.rb" Nothing [__i|puts "hi"|] (Position 0 2) $ \hover -> do
+    itHasHoverSatisfying "solargraph" "test.rb" [__i|puts "hi"|] (Position 0 2) $ \hover -> do
       let InL (MarkupContent MarkupKind_Markdown text) = hover ^. contents
       text `textShouldContain` "Kernel#puts"
       text `textShouldContain` "$stdout.puts(obj"
diff --git a/tests/app/Spec/Tests/Rust/Diagnostics.hs b/tests/app/Spec/Tests/Rust/Diagnostics.hs
index cc43fc92..1fbc1150 100644
--- a/tests/app/Spec/Tests/Rust/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Rust/Diagnostics.hs
@@ -14,16 +14,16 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Diagnostics" $ do
-  testDiagnostics "rust-analyzer" "main.ipynb" Nothing [__i|printlnz!("Hello world");
-                                                           |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "main.ipynb" [__i|printlnz!("Hello world");
+                                                   |] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [
       (Range (Position 0 0) (Position 0 8), Nothing, "cannot find macro `printlnz` in this scope")
       , (Range (Position 0 0) (Position 0 8), Nothing, "a macro with a similar name exists: `println`")
       ]
 
-  testDiagnostics "rust-analyzer" "test.rs" Nothing [__i|struct A { a: u8, b: u8 }
-                                                         const a: A = A { a: 10, };
-                                                        |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "test.rs" [__i|struct A { a: u8, b: u8 }
+                                                 const a: A = A { a: 10, };
+                                                |] $ \diagnostics -> do
     assertDiagnosticRanges' (L.sortBy (compare `on` (^. LSP.message)) diagnostics) [
       (Range (Position 1 13) (Position 1 14), Just (InR "E0063"), "missing field `b` in initializer of `A`\nmissing `b`")
       -- (Range (Position 1 6) (Position 1 7), Just (InR "non_upper_case_globals"), "Constant `a` should have UPPER_SNAKE_CASE name, e.g. `A`")
@@ -31,10 +31,10 @@ tests = describe "Diagnostics" $ do
       -- , (Range (Position 1 13) (Position 1 14), Just (InR "E0063"), "missing structure fields:\n- b\n")
       ]
 
-  testDiagnostics "rust-analyzer" "main.ipynb" Nothing [__i|println!("Hello world");
-                                                            eprintln!("Hello error");
-                                                            format!("Hello {}", "world")
-                                                           |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "main.ipynb" [__i|println!("Hello world");
+                                                    eprintln!("Hello error");
+                                                    format!("Hello {}", "world")
+                                                   |] $ \diagnostics -> do
     assertDiagnosticRanges' (L.sortBy (compare `on` (^. LSP.message)) diagnostics) [
       (Range (Position 2 0) (Position 2 28), Just (InR "E0308"), "mismatched types\nexpected `()`, found `String`")
       ]
diff --git a/tests/app/Spec/Tests/Spellchecker.hs b/tests/app/Spec/Tests/Spellchecker.hs
index 6aee19be..034a836b 100644
--- a/tests/app/Spec/Tests/Spellchecker.hs
+++ b/tests/app/Spec/Tests/Spellchecker.hs
@@ -29,9 +29,7 @@ otherConfig = [
 tests :: TopSpec
 tests = describe "Spellchecker" $ introduceNixEnvironment [] otherConfig "Spellchecker env" $ introduceJustBubblewrap $ do
   it "Gets diagnostics and a working code action" $ do
-    lspConfig <- findLspConfig "spellchecker"
-    (pathToUse, closure) <- getPathAndNixEnvironmentClosure
-    withLspSession lspConfig pathToUse closure "test.md" [i|\# This is mispelled|] [] $ \lspHomeDir -> do
+    doSession'' "test.md" "spellchecker" [i|\# This is mispelled|] [] $ \lspHomeDir -> do
       ident <- openDoc "test.md" "spellchecker"
       waitUntil 300.0 $ do
         diagnostics <- waitForDiagnostics
@@ -51,16 +49,14 @@ tests = describe "Spellchecker" $ introduceNixEnvironment [] otherConfig "Spellc
         liftIO (T.readFile datPath) >>= (`shouldBe` "mispelled\n")
 
   it "Uses a personal dictionary on startup" $ do
-    lspConfig <- findLspConfig "spellchecker"
-    (pathToUse, closure) <- getPathAndNixEnvironmentClosure
     let extraFiles = [(".codedown/personal-dictionary.dat", "mispelled\n")]
-    withLspSession' id lspConfig pathToUse closure "test.md" [i|\# This is mispelled|] extraFiles $ \_homeDir -> do
+    doSession'' "test.md" "spellchecker" [i|\# This is mispelled|] extraFiles $ \_homeDir -> do
       _ident <- openDoc "test.md" "spellchecker"
       waitUntil 300.0 $ do
         diagnostics <- waitForDiagnostics
         lift $ assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "spellchecker" "test.md" Nothing [i|I've done a thing.|] $ \diagnostics -> do
+  testDiagnostics "spellchecker" "test.md" [i|I've done a thing.|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
 
diff --git a/tests/app/Spec/Tests/Typst.hs b/tests/app/Spec/Tests/Typst.hs
index b5f1cbe7..2f4ebfad 100644
--- a/tests/app/Spec/Tests/Typst.hs
+++ b/tests/app/Spec/Tests/Typst.hs
@@ -35,7 +35,7 @@ tests = describe [i|Typst|] $ introduceNixEnvironment [] config [i|Typst|] $ int
     void $ testBuild [i|exporters.typst.packageSearch|]
 
   describe "LSP" $ do
-    testDiagnosticsLabelDesired "simple" lsName "test.typ" (Just "typst")
+    testDiagnosticsLabelDesired "simple" lsName "test.typ"
       [__i|\#loremz(45)|]
       ((== [(Range (Position 0 1) (Position 0 7), Nothing, "unknown variable: loremz")]) . getDiagnosticRanges')
 
diff --git a/tests/src/TestLib/LSP.hs b/tests/src/TestLib/LSP.hs
index 3d4c6451..c314a30c 100644
--- a/tests/src/TestLib/LSP.hs
+++ b/tests/src/TestLib/LSP.hs
@@ -10,12 +10,10 @@ module TestLib.LSP (
 
   , doNotebookSession
   , doSession'
+  , doSession''
 
-  , withLspSession
-  , withLspSession'
-
-  , getDiagnosticRanges
-  , getDiagnosticRanges'
+  , Helpers.getDiagnosticRanges
+  , Helpers.getDiagnosticRanges'
   , assertDiagnosticRanges
   , assertDiagnosticRanges'
   , testDiagnostics
@@ -23,96 +21,40 @@ module TestLib.LSP (
   , testDiagnosticsLabelDesired
   , testDiagnostics''
 
-  , getHoverOrException
-  , allHoverText
   , itHasHoverSatisfying
 
-  , containsAll
+  , Helpers.getHoverOrException
+  , Helpers.allHoverText
+  , Helpers.containsAll
 
   , LspContext
   ) where
 
-import Control.Applicative
-import Control.Lens hiding (List)
 import Control.Monad
-import Control.Monad.Catch as C (MonadCatch, MonadMask, MonadThrow)
 import Control.Monad.IO.Unlift
-import Control.Monad.Logger (MonadLogger, MonadLoggerIO)
+import Control.Monad.Logger (MonadLogger)
 import Control.Monad.Reader
-import Control.Monad.Trans.Control (MonadBaseControl)
 import Data.Aeson as A
-import Data.Aeson.TH as A
 import qualified Data.ByteString as B
-import Data.Default
-import Data.Function
 import qualified Data.List as L
-import Data.Map (Map)
-import qualified Data.Map as M
 import Data.Maybe
-import qualified Data.Set as S
 import Data.String.Interpolate
 import qualified Data.Text as T hiding (filter)
 import Data.Text hiding (filter, show)
-import qualified Data.Text.IO as T
 import GHC.Int
 import GHC.Stack
-import Language.LSP.Protocol.Capabilities
-import Language.LSP.Protocol.Lens as LSP hiding (diagnostics, hover, id, label, name, ranges)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test
+import Language.LSP.Test.Helpers (LanguageServerConfig(..), LspContext, LspSessionOptions(..), defaultLspSessionOptions, withLspSession)
+import qualified Language.LSP.Test.Helpers as Helpers
 import System.FilePath
-import System.IO.Temp (createTempDirectory)
 import Test.Sandwich as Sandwich
-import Test.Sandwich.Waits (waitUntil)
-import TestLib.Aeson
 import TestLib.Types
-import UnliftIO.Async
 import UnliftIO.Directory
 import UnliftIO.Exception
 import UnliftIO.IO
-import UnliftIO.IORef
 import UnliftIO.Process
-import UnliftIO.STM
-
-
-data LanguageServerType = LanguageServerTypeTcp
-                        | LanguageServerTypeStream
-  deriving (Show, Eq)
-deriveJSON toSnakeC3 ''LanguageServerType
-
-data LanguageServerConfig = LanguageServerConfig {
-  lspConfigName :: Text
-  , lspConfigVersion :: Maybe Text
-  , lspConfigDescription :: Maybe Text
-  , lspConfigDisplayName :: Maybe Text
-  , lspConfigIcon :: Maybe FilePath
-  , lspConfigExtensions :: [Text]
-  , lspConfigAttrs :: S.Set Text
-  , lspConfigType :: LanguageServerType
-  , lspConfigPrimary :: Maybe Bool
-  , lspConfigArgs :: [Text]
-  , lspConfigLanguageId :: Maybe Text
-  , lspConfigInitializationOptions :: Maybe A.Object
-  , lspConfigNotebookSuffix :: Text
-  , lspConfigKernelName :: Maybe Text
-  , lspConfigEnv :: Maybe (Map Text Text)
-  , lspConfigFile :: Maybe FilePath
-  , lspConfigIsBuiltIn :: Maybe Bool
-  } deriving (Show, Eq)
-deriveJSON toSnake2 ''LanguageServerConfig
-
-type LspContext ctx m = (
-  Alternative m
-  , MonadIO m
-  , MonadBaseControl IO m
-  , MonadUnliftIO m
-  , MonadCatch m
-  , MonadThrow m
-  , MonadMask m
-
-  , HasBaseContext ctx
-  , HasMaybeBubblewrap ctx
-  )
+
 
 doNotebookSession :: (
   LspContext ctx m, HasNixEnvironment ctx
@@ -130,156 +72,90 @@ doSession'' :: (
 doSession'' filename lsName codeToUse extraFiles cb = do
   lspConfig <- findLspConfig lsName
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
-  withLspSession lspConfig pathToUse closure (T.unpack filename) codeToUse extraFiles $ \_homeDir -> do
+  let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
+        lspSessionOptionsInitialFileName = T.unpack filename
+        , lspSessionOptionsInitialCode = codeToUse
+        , lspSessionOptionsExtraFiles = extraFiles
+        , lspSessionOptionsReadOnlyBinds = closure
+        , lspSessionOptionsPathEnvVar = pathToUse
+        }
+  withLspSession lspSessionOptions $ \_homeDir -> do
     cb (T.unpack filename)
 
 testDiagnostics :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Maybe LanguageKind -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics name filename maybeLanguageId codeToTest = testDiagnostics' name filename maybeLanguageId codeToTest []
+  ) => Text -> FilePath -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics name filename code = testDiagnostics' name filename code []
 
 testDiagnostics' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Maybe LanguageKind -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics' name filename maybeLanguageId codeToTest = testDiagnostics'' [i|#{name}, #{filename} with #{show codeToTest} (diagnostics)|] name filename maybeLanguageId codeToTest
+  ) => Text -> FilePath -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics' name filename codeToTest = testDiagnostics'' [i|#{name}, #{filename} with #{show codeToTest} (diagnostics)|] name filename codeToTest
 
 testDiagnosticsLabel :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath -> Maybe LanguageKind -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnosticsLabel label name filename maybeLanguageId codeToTest = testDiagnostics'' label name filename maybeLanguageId codeToTest []
+  ) => String -> Text -> FilePath -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnosticsLabel label name filename codeToTest = testDiagnostics'' label name filename codeToTest []
 
 testDiagnosticsLabelDesired :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath -> Maybe LanguageKind -> Text -> ([Diagnostic] -> Bool) -> SpecFree ctx m ()
-testDiagnosticsLabelDesired label name filename maybeLanguageId codeToTest cb = it label $ do
+  ) => String -> Text -> FilePath -> Text -> ([Diagnostic] -> Bool) -> SpecFree ctx m ()
+testDiagnosticsLabelDesired label name filename code cb = it label $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
-  withLspSession' id lspConfig pathToUse closure filename codeToTest [] $ \_homeDir -> do
-    _ <- openDoc filename (fromMaybe (LanguageKind_Custom name) maybeLanguageId)
+  let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
+        lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialCode = code
+        , lspSessionOptionsReadOnlyBinds = closure
+        , lspSessionOptionsPathEnvVar = pathToUse
+        }
 
-    lastSeenDiagsVar <- newTVarIO mempty
+  Helpers.testDiagnostics lspSessionOptions $ \diags ->
+    if | cb diags -> return True
+       | otherwise -> expectationFailure [i|Got unexpected diagnostics: #{diags}|]
 
-    let watchDiagnostics = forever $ do
-          diags <- waitForDiagnostics
-          atomically $ writeTVar lastSeenDiagsVar diags
-
-    withAsync watchDiagnostics $ \_ -> do
-      waitUntil 60.0 $ do
-        flip fix [] $ \loop lastValue ->
-          if | cb lastValue -> return ()
-             | otherwise -> do
-                 newDiags <- atomically $ do
-                   x <- readTVar lastSeenDiagsVar
-                   when (x == lastValue) retrySTM
-                   return x
-                 loop newDiags
 
 testDiagnostics'' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath -> Maybe LanguageKind -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics'' label name filename maybeLanguageId codeToTest extraFiles cb = it label $ do
+  ) => String -> Text -> FilePath-> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics'' label name filename code extraFiles cb = it label $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
-  withLspSession' id lspConfig pathToUse closure filename codeToTest extraFiles $ \_homeDir -> do
-    _ <- openDoc filename (fromMaybe (LanguageKind_Custom name) maybeLanguageId)
+  let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
+        lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialCode = code
+        , lspSessionOptionsReadOnlyBinds = closure
+        , lspSessionOptionsPathEnvVar = pathToUse
+        , lspSessionOptionsExtraFiles = extraFiles
+        }
 
-    lastSeenDiagsVar <- newIORef mempty
+  Helpers.testDiagnostics lspSessionOptions $ \diags -> do
+    lift $ cb diags
+    return True
 
-    waitUntil 60.0 $ do
-      diags <- waitForDiagnostics
-      writeIORef lastSeenDiagsVar diags
-      withException (lift $ cb diags) $ \(e :: SomeException) -> do
-        lastSeenDiags <- readIORef lastSeenDiagsVar
-        logError [i|Exception in testDiagnostics'': #{e}.\n\nLast seen diagnostics: #{A.encode lastSeenDiags}|]
 
 itHasHoverSatisfying :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Maybe LanguageKind -> Text -> Position -> (Hover -> ExampleT ctx m ()) -> SpecFree ctx m ()
-itHasHoverSatisfying name filename maybeLanguageId codeToTest pos cb = it [i|#{name}: #{show codeToTest} (hover)|] $ do
+  ) => Text -> FilePath -> Text -> Position -> (Hover -> ExampleT ctx m ()) -> SpecFree ctx m ()
+itHasHoverSatisfying name filename code pos cb = it [i|#{name}: #{show code} (hover)|] $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
-  withLspSession lspConfig pathToUse closure filename codeToTest [] $ \_homeDir -> do
-    ident <- openDoc filename (fromMaybe (LanguageKind_Custom name) maybeLanguageId)
+  let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
+        lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialCode = code
+        , lspSessionOptionsReadOnlyBinds = closure
+        , lspSessionOptionsPathEnvVar = pathToUse
+        }
+
+  withLspSession lspSessionOptions $ \_ -> do
+    ident <- openDoc filename (fromMaybe (LanguageKind_Custom "unknown") (lspConfigLanguageId lspConfig))
     getHover ident pos >>= \case
       Nothing -> expectationFailure [i|Expected a hover.|]
       Just x -> lift $ cb x
 
-withLspSession :: (
-  LspContext ctx m
-  ) => LanguageServerConfig -> FilePath -> [FilePath] -> FilePath -> Text -> [(FilePath, B.ByteString)] -> (FilePath -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
-withLspSession = withLspSession' handleSessionException
-
-handleSessionException :: MonadUnliftIO m => ExampleT ctx m a -> ExampleT ctx m a
-handleSessionException = handle (\(e :: SessionException) -> expectationFailure [i|LSP session failed with SessionException: #{e}|])
-
-withLspSession' :: (
-  LspContext ctx m
-  ) => (ExampleT ctx m a -> ExampleT ctx m a) -> LanguageServerConfig -> FilePath -> [FilePath] -> FilePath -> Text -> [(FilePath, B.ByteString)] -> (FilePath -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
-withLspSession' handleFn config pathToUse fullClosure filename codeToTest extraFiles session = do
-  Just currentFolder <- getCurrentFolder
-
-  homeDir <- liftIO $ createTempDirectory currentFolder "home"
-
-  forM_ extraFiles $ \(path, bytes) -> do
-    unless (isAbsolute path) $ do
-      debug [i|Writing extra file: #{homeDir </> path}|]
-      createDirectoryIfMissing True (homeDir </> takeDirectory path)
-      liftIO $ B.writeFile (homeDir </> path) bytes
-
-  createDirectoryIfMissing True (homeDir </> takeDirectory filename)
-
-  -- Comment this and use openDoc' to simulate an unsaved document
-  liftIO $ T.writeFile (homeDir </> filename) codeToTest
-
-  let sessionConfig = def { lspConfig = fromMaybe mempty (lspConfigInitializationOptions config)
-                          , logStdErr = True
-                          , logMessages = True
-                          , messageTimeout = 120
-                          }
-
-  let cmd:args = fmap T.unpack $ lspConfigArgs config
-  (cp, modifyCp) <- getContext maybeBubblewrap >>= \case
-    Nothing -> do
-      let configEnv = maybe mempty (fmap (bimap T.unpack T.unpack) . M.toList) (lspConfigEnv config)
-      let finalEnv = ("HOME", homeDir) : ("PATH", pathToUse) : configEnv
-      info [i|Language server environment: #{finalEnv}|]
-      let modifyCp cp = cp { env = Just finalEnv
-                           , cwd = Just homeDir }
-      return (proc cmd args, modifyCp)
-    Just bwrapBinary -> do
-      let bwrapArgs = ["--tmpfs", "/tmp"
-                      , "--bind", homeDir, homeDir
-                      , "--clearenv"
-                      , "--setenv", "HOME", homeDir
-                      , "--chdir", homeDir
-
-                      , "--setenv", "PATH", pathToUse
-
-                      , "--proc", "/proc"
-                      , "--dev", "/dev"
-                      ]
-                      <> mconcat [["--ro-bind", x, x] | x <- fullClosure]
-                      <> mconcat [["--setenv", T.unpack n, T.unpack v] | (n, v) <- M.toList (fromMaybe mempty (lspConfigEnv config))]
-                      <> ["--"]
-                      <> (cmd : args)
-
-      return (proc bwrapBinary bwrapArgs, id)
-
-  info [i|LSP command: #{cp}|]
-
-  -- We don't support certain server-to-client requests, since the waitForDiagnostics doesn't handle them
-  let caps = fullClientCapsForVersion (LSPVersion 3 16)
-           & set (workspace . _Just . workspaceFolders) Nothing
-           & set (workspace . _Just . configuration) Nothing
-           & set (workspace . _Just . didChangeWatchedFiles . _Just . dynamicRegistration) (Just False)
-           & set (workspace . _Just . didChangeConfiguration . _Just . dynamicRegistration) (Just False)
-           & set (textDocument . _Just . semanticTokens . _Just . dynamicRegistration) (Just False)
-
-  handleFn $ runSessionWithConfigCustomProcess modifyCp sessionConfig cp caps homeDir (session homeDir)
-
 findLspConfig :: (
   MonadIO m, MonadLogger m, MonadReader context m, Sandwich.HasLabel context "nixEnvironment" FilePath
   ) => Text -> m LanguageServerConfig
@@ -335,10 +211,7 @@ assertDiagnosticRanges diagnostics desired = if
                               Found: #{A.encode found}
                              |]
   where
-    found = getDiagnosticRanges diagnostics
-
-getDiagnosticRanges :: [Diagnostic] -> [(Range, Maybe (Int32 |? Text))]
-getDiagnosticRanges = fmap (\x -> (x ^. range, x ^. code))
+    found = Helpers.getDiagnosticRanges diagnostics
 
 assertDiagnosticRanges' :: (HasCallStack, MonadIO m) => [Diagnostic] -> [(Range, Maybe (Int32 |? Text), Text)] -> m ()
 assertDiagnosticRanges' diagnostics desired = if
@@ -351,34 +224,4 @@ assertDiagnosticRanges' diagnostics desired = if
                               Found: #{A.encode found}
                              |]
   where
-    found = getDiagnosticRanges' diagnostics
-
-getDiagnosticRanges' :: [Diagnostic] -> [(Range, Maybe (Int32 |? Text), Text)]
-getDiagnosticRanges' = fmap (\x -> (x ^. range, x ^. code, x ^. LSP.message))
-
--- hoverShouldSatisfy :: MonadThrow m => Position -> (Maybe Hover -> ExampleT ctx m ()) -> ExampleT ctx m ()
--- hoverShouldSatisfy pos pred = getHover (TextDocumentIdentifier (Uri undefined)) pos >>= pred
-
-getHoverOrException :: (
-  MonadLoggerIO m, MonadThrow m, MonadUnliftIO m, Alternative m
-  ) => TextDocumentIdentifier -> Position -> Session m Hover
-getHoverOrException tdi pos = getHover tdi pos >>= \case
-  Nothing -> expectationFailure [i|No hover returned.|]
-  Just x -> return x
-
-allHoverText :: Hover -> Text
-allHoverText hover = allHoverContentsText (hover ^. contents)
-
-type HoverContents = MarkupContent |? (MarkedString |? [MarkedString])
-
-allHoverContentsText :: HoverContents -> Text
-allHoverContentsText (InL (MarkupContent _ t)) = t
-allHoverContentsText (InR markedStrings) = case markedStrings of
-  InL ms -> markedStringToText ms
-  InR mss -> mconcat $ fmap markedStringToText mss
-  where
-    markedStringToText (MarkedString (InL t)) = t
-    markedStringToText (MarkedString (InR thing)) = thing ^. LSP.value
-
-containsAll :: Text -> [Text] -> Bool
-containsAll haystack = Prelude.all (`T.isInfixOf` haystack)
+    found = Helpers.getDiagnosticRanges' diagnostics
diff --git a/tests/stack.yaml b/tests/stack.yaml
index 1b4dd057..df0651f1 100644
--- a/tests/stack.yaml
+++ b/tests/stack.yaml
@@ -3,6 +3,7 @@ resolver: nightly-2025-12-25
 
 packages:
 - .
+# - /home/tom/tools/lsp-test-helpers
 
 nix:
   enable: false
@@ -18,6 +19,10 @@ extra-deps:
   - lsp-test
   - lsp-types
 
+- git: https://github.com/codedownio/lsp-test-helpers.git
+  # main branch
+  commit: 10a74a28168b56428ab7c465d8e25e4d9e4e4734
+
 - ex-pool-0.2.1@sha256:c8249338ced27bc4d6395ad9c3069eec394fb111813d6ec736814d095f7e6a24,1293
 
 - git: https://github.com/codedownio/minio-hs

From 6848fdab9da1e8cceb806686836015c045e280a6 Mon Sep 17 00:00:00 2001
From: Tom McLaughlin <tom@codedown.io>
Date: Sun, 11 Jan 2026 18:03:32 -0800
Subject: [PATCH 2/5] Fill in language_id for LSP configs

---
 modules/kernels/bash/language_server_bash/default.nix           | 1 +
 modules/kernels/clojure/language-server.nix                     | 1 +
 modules/kernels/cpp/language_server_clangd/default.nix          | 1 +
 modules/kernels/go/language-server-gopls.nix                    | 1 +
 modules/kernels/haskell/language-server-hls/config.nix          | 2 ++
 .../python/language_servers/language_server_flake8/config.nix   | 1 +
 .../python/language_servers/language_server_jedi/config.nix     | 1 +
 .../language_servers/language_server_microsoft/config.nix       | 1 +
 .../python/language_servers/language_server_palantir/config.nix | 1 +
 .../language_servers/language_server_pycodestyle/config.nix     | 1 +
 .../python/language_servers/language_server_pylint/config.nix   | 1 +
 .../python/language_servers/language_server_pyright/config.nix  | 2 ++
 .../language_servers/language_server_pythonlsp/config.nix       | 1 +
 modules/kernels/r/language-server-languageserver/default.nix    | 1 +
 modules/kernels/ruby/solargraph.nix                             | 1 +
 modules/kernels/rust/language_server_rust_analyzer/config.nix   | 2 ++
 16 files changed, 19 insertions(+)

diff --git a/modules/kernels/bash/language_server_bash/default.nix b/modules/kernels/bash/language_server_bash/default.nix
index 02e94518..e59b301e 100644
--- a/modules/kernels/bash/language_server_bash/default.nix
+++ b/modules/kernels/bash/language_server_bash/default.nix
@@ -48,4 +48,5 @@ common.writeTextDirWithMetaAndPassthru bashLanguageServerWithMan.meta passthru "
     "${bashLanguageServerWithMan}/bin/bash-language-server"
     "start"
   ];
+  language_id = "shellscript";
 }])
diff --git a/modules/kernels/clojure/language-server.nix b/modules/kernels/clojure/language-server.nix
index 5a9127de..f7821705 100644
--- a/modules/kernels/clojure/language-server.nix
+++ b/modules/kernels/clojure/language-server.nix
@@ -30,4 +30,5 @@ common.writeTextDirWithMetaAndPassthru clojure-lsp.meta passthru "lib/codedown/l
   type = "stream";
   args = ["${clojure-lsp}/bin/clojure-lsp"];
   env = {};
+  language_id = "clojure";
 }])
diff --git a/modules/kernels/cpp/language_server_clangd/default.nix b/modules/kernels/cpp/language_server_clangd/default.nix
index d428a430..87c93d17 100644
--- a/modules/kernels/cpp/language_server_clangd/default.nix
+++ b/modules/kernels/cpp/language_server_clangd/default.nix
@@ -29,4 +29,5 @@ common.writeTextDirWithMetaAndPassthru clangd.meta passthru "lib/codedown/langua
   args = [
     "${clangd}/bin/clangd"
   ];
+  language_id = "cpp";
 }])
diff --git a/modules/kernels/go/language-server-gopls.nix b/modules/kernels/go/language-server-gopls.nix
index 6d87f58f..5ae18552 100644
--- a/modules/kernels/go/language-server-gopls.nix
+++ b/modules/kernels/go/language-server-gopls.nix
@@ -45,6 +45,7 @@ common.writeTextDirWithMetaAndPassthru gopls.meta passthru "lib/codedown/languag
   type = "stream";
   args = ["${goplsWrapped}/bin/gopls"];
   env = {};
+  language_id = "go";
 }])
 
 
diff --git a/modules/kernels/haskell/language-server-hls/config.nix b/modules/kernels/haskell/language-server-hls/config.nix
index 7eb78056..188376d6 100644
--- a/modules/kernels/haskell/language-server-hls/config.nix
+++ b/modules/kernels/haskell/language-server-hls/config.nix
@@ -81,6 +81,8 @@ let
         # checkParents = "CheckOnSave";
       };
     };
+
+    language_id = "haskell";
   };
 
 in
diff --git a/modules/kernels/python/language_servers/language_server_flake8/config.nix b/modules/kernels/python/language_servers/language_server_flake8/config.nix
index b242a320..59a9f466 100644
--- a/modules/kernels/python/language_servers/language_server_flake8/config.nix
+++ b/modules/kernels/python/language_servers/language_server_flake8/config.nix
@@ -81,4 +81,5 @@ common.writeTextDirWithMetaAndPassthru python.pkgs.flake8.meta passthru "lib/cod
       formatters = {};
       formatFiletypes = {};
     };
+    language_id = "python";
   }])
diff --git a/modules/kernels/python/language_servers/language_server_jedi/config.nix b/modules/kernels/python/language_servers/language_server_jedi/config.nix
index e406c540..52b2b97a 100644
--- a/modules/kernels/python/language_servers/language_server_jedi/config.nix
+++ b/modules/kernels/python/language_servers/language_server_jedi/config.nix
@@ -40,4 +40,5 @@ common.writeTextDirWithMetaAndPassthru jls.meta passthru "lib/codedown/language-
       "/home/user/.local/${pythonEnv.sitePackages}"
     ];
   };
+  language_id = "python";
 }])
diff --git a/modules/kernels/python/language_servers/language_server_microsoft/config.nix b/modules/kernels/python/language_servers/language_server_microsoft/config.nix
index 1abc0233..a33132a8 100644
--- a/modules/kernels/python/language_servers/language_server_microsoft/config.nix
+++ b/modules/kernels/python/language_servers/language_server_microsoft/config.nix
@@ -88,4 +88,5 @@ common.writeTextDirWithMetaAndPassthru python-language-server.meta passthru "lib
     initialization_options = overrideExisting initialization_options {
       # cacheFolderPath = "${cache}/cache";
     };
+    language_id = "python";
   }])
diff --git a/modules/kernels/python/language_servers/language_server_palantir/config.nix b/modules/kernels/python/language_servers/language_server_palantir/config.nix
index 864442fc..5ca16d71 100644
--- a/modules/kernels/python/language_servers/language_server_palantir/config.nix
+++ b/modules/kernels/python/language_servers/language_server_palantir/config.nix
@@ -61,4 +61,5 @@ common.writeTextDirWithMetaAndPassthru python.pkgs.python-language-server.meta p
     type = "stream";
     args = ["${python}/bin/python" "-m" "pyls"];
     initialization_options = import ../pylsp_initialization_options.nix "pyls";
+    language_id = "python";
   }])
diff --git a/modules/kernels/python/language_servers/language_server_pycodestyle/config.nix b/modules/kernels/python/language_servers/language_server_pycodestyle/config.nix
index 0f5679d7..eaa21a81 100644
--- a/modules/kernels/python/language_servers/language_server_pycodestyle/config.nix
+++ b/modules/kernels/python/language_servers/language_server_pycodestyle/config.nix
@@ -80,4 +80,5 @@ common.writeTextDirWithMetaAndPassthru python.pkgs.pycodestyle.meta passthru "li
       formatters = {};
       formatFiletypes = {};
     };
+    language_id = "python";
   }])
diff --git a/modules/kernels/python/language_servers/language_server_pylint/config.nix b/modules/kernels/python/language_servers/language_server_pylint/config.nix
index e4a1c304..802a2295 100644
--- a/modules/kernels/python/language_servers/language_server_pylint/config.nix
+++ b/modules/kernels/python/language_servers/language_server_pylint/config.nix
@@ -90,4 +90,5 @@ common.writeTextDirWithMetaAndPassthru python.pkgs.pylint.meta passthru "lib/cod
       formatters = {};
       formatFiletypes = {};
     };
+    language_id = "python";
   }])
diff --git a/modules/kernels/python/language_servers/language_server_pyright/config.nix b/modules/kernels/python/language_servers/language_server_pyright/config.nix
index fea5420f..3f09c76f 100644
--- a/modules/kernels/python/language_servers/language_server_pyright/config.nix
+++ b/modules/kernels/python/language_servers/language_server_pyright/config.nix
@@ -64,4 +64,6 @@ common.writeTextDirWithMetaAndPassthru pyright.meta passthru "lib/codedown/langu
     # We need to send empty string, otherwise  pyright-langserver fails with parse error
     # "python.venvPath" = "";
   };
+
+  language_id = "python";
 }])
diff --git a/modules/kernels/python/language_servers/language_server_pythonlsp/config.nix b/modules/kernels/python/language_servers/language_server_pythonlsp/config.nix
index 25825dba..0b7bad18 100644
--- a/modules/kernels/python/language_servers/language_server_pythonlsp/config.nix
+++ b/modules/kernels/python/language_servers/language_server_pythonlsp/config.nix
@@ -62,4 +62,5 @@ common.writeTextDirWithMetaAndPassthru python.pkgs.python-lsp-server.meta passth
     type = "stream";
     args = ["${python}/bin/python" "-m" "pylsp"];
     initialization_options = import ../pylsp_initialization_options.nix "pylsp";
+    language_id = "python";
   }])
diff --git a/modules/kernels/r/language-server-languageserver/default.nix b/modules/kernels/r/language-server-languageserver/default.nix
index 2424f2f0..0c7404eb 100644
--- a/modules/kernels/r/language-server-languageserver/default.nix
+++ b/modules/kernels/r/language-server-languageserver/default.nix
@@ -37,4 +37,5 @@ common.writeTextDirWithMetaAndPassthru languageserver.meta passthru "lib/codedow
   type = "stream";
   primary = true;
   args = ["${rWithPackagesAndLanguageServer}/bin/R" "--slave" "-e" "languageserver::run()"];
+  language_id = "r";
 }])
diff --git a/modules/kernels/ruby/solargraph.nix b/modules/kernels/ruby/solargraph.nix
index c5f80c4d..6e9972e6 100644
--- a/modules/kernels/ruby/solargraph.nix
+++ b/modules/kernels/ruby/solargraph.nix
@@ -30,4 +30,5 @@ common.writeTextDirWithMetaAndPassthru solargraph.meta passthru "lib/codedown/la
   attrs = ["ruby"];
   type = "stream";
   args = ["${solargraph}/bin/solargraph" "stdio"];
+  language_id = "ruby";
 }])
diff --git a/modules/kernels/rust/language_server_rust_analyzer/config.nix b/modules/kernels/rust/language_server_rust_analyzer/config.nix
index 1d233a5d..575d1c97 100644
--- a/modules/kernels/rust/language_server_rust_analyzer/config.nix
+++ b/modules/kernels/rust/language_server_rust_analyzer/config.nix
@@ -174,6 +174,8 @@ let
 
       # "RA_LOG" = "rust_analyzer=info";
     };
+
+    language_id = "rust";
   };
 
 in

From afc2016621da6d878d00e5ff8469e5279669fa18 Mon Sep 17 00:00:00 2001
From: Tom McLaughlin <tom@codedown.io>
Date: Sun, 11 Jan 2026 18:04:45 -0800
Subject: [PATCH 3/5] More progress switching to lsp-test-helpers

---
 tests/app/Spec/Tests/Bash.hs                  |  2 +-
 tests/app/Spec/Tests/Clojure.hs               |  2 +-
 tests/app/Spec/Tests/Cpp.hs                   |  2 +-
 tests/app/Spec/Tests/Go.hs                    |  2 +-
 tests/app/Spec/Tests/Haskell/CodeActions.hs   |  9 +--
 tests/app/Spec/Tests/Haskell/Diagnostics.hs   | 12 ++--
 .../Spec/Tests/Haskell/DocumentHighlight.hs   |  9 +--
 tests/app/Spec/Tests/Haskell/Hover.hs         |  9 +--
 tests/app/Spec/Tests/Haskell/Statements.hs    | 13 ++--
 tests/app/Spec/Tests/Haskell/Symbols.hs       |  5 +-
 tests/app/Spec/Tests/Julia.hs                 |  7 +-
 tests/app/Spec/Tests/Julia/Diagnostics.hs     |  8 +--
 tests/app/Spec/Tests/Python.hs                | 22 +++---
 tests/app/Spec/Tests/Ruby.hs                  |  2 +-
 tests/app/Spec/Tests/Rust/Changes.hs          |  5 +-
 tests/app/Spec/Tests/Rust/Completion.hs       |  5 +-
 tests/app/Spec/Tests/Rust/Diagnostics.hs      | 17 +++--
 tests/app/Spec/Tests/Rust/Hovers.hs           |  5 +-
 tests/app/Spec/Tests/Spellchecker.hs          |  7 +-
 tests/app/Spec/Tests/Typst.hs                 |  2 +-
 tests/package.yaml                            |  5 +-
 tests/src/TestLib/LSP.hs                      | 72 ++++++++-----------
 tests/stack.yaml                              |  5 +-
 tests/stack.yaml.lock                         | 22 +++---
 tests/tests.cabal                             |  6 +-
 25 files changed, 123 insertions(+), 132 deletions(-)

diff --git a/tests/app/Spec/Tests/Bash.hs b/tests/app/Spec/Tests/Bash.hs
index 9b347d25..bea91966 100644
--- a/tests/app/Spec/Tests/Bash.hs
+++ b/tests/app/Spec/Tests/Bash.hs
@@ -37,7 +37,7 @@ tests = describe "Bash" $ introduceNixEnvironment [kernelSpec] [] "Bash" $ intro
   --                                            |] $ \diagnostics -> do
   --   assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "bash-language-server" "test.sh" [__i|FOO=42|] $ \diagnostics -> do
+  testDiagnostics "bash-language-server" "test.sh" LanguageKind_ShellScript [__i|FOO=42|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics [
       (Range (Position 0 0) (Position 0 3), Just (InR "SC2034"))
       ]
diff --git a/tests/app/Spec/Tests/Clojure.hs b/tests/app/Spec/Tests/Clojure.hs
index 1a027d2b..c74cf848 100644
--- a/tests/app/Spec/Tests/Clojure.hs
+++ b/tests/app/Spec/Tests/Clojure.hs
@@ -31,7 +31,7 @@ tests = describe "Clojure" $ introduceNixEnvironment [kernelSpec] [] "Clojure" $
 
   testKernelStdout "clojure" [__i|(println "hi")|] "hi\n"
 
-  testDiagnostics "clojure-lsp" "test.clj" [__i|(foo 42)|] $ \diagnostics -> do
+  testDiagnostics "clojure-lsp" "test.clj" LanguageKind_Clojure [__i|(foo 42)|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics [(Range (Position 0 1) (Position 0 4), Just (InR "unresolved-symbol"))]
 
 
diff --git a/tests/app/Spec/Tests/Cpp.hs b/tests/app/Spec/Tests/Cpp.hs
index 1120d69f..ff32492a 100644
--- a/tests/app/Spec/Tests/Cpp.hs
+++ b/tests/app/Spec/Tests/Cpp.hs
@@ -40,7 +40,7 @@ tests' flavor = describe [i|C++ (#{flavor})|] $ introduceNixEnvironment [kernelS
 testsWithLsp :: Text -> LanguageSpec
 testsWithLsp flavor = describe [i|C++ (#{flavor}) with LSP|] $ introduceNixEnvironment [kernelSpecWithLsp flavor] [] "C++" $ do
   describe "LSP" $ do
-    testDiagnostics'' "simple" lsName "test.cpp"
+    testDiagnostics'' "simple" lsName "test.cpp" LanguageKind_CPP
       [__i|int main() {
              undefined_function();
              return 0;
diff --git a/tests/app/Spec/Tests/Go.hs b/tests/app/Spec/Tests/Go.hs
index 521b86d7..3ad5fcca 100644
--- a/tests/app/Spec/Tests/Go.hs
+++ b/tests/app/Spec/Tests/Go.hs
@@ -33,7 +33,7 @@ tests = describe "Go" $ introduceNixEnvironment [kernelSpec] [] "Go" $ introduce
   testKernelStdout "go" [__i|import("fmt")
                              fmt.Println("hi")|] "hi\n"
 
-  testDiagnosticsLabel "gopls: Undeclared name" "gopls" "test.go" printUnknownCode $ \diagnostics ->
+  testDiagnosticsLabel "gopls: Undeclared name" "gopls" "test.go" LanguageKind_Go printUnknownCode $ \diagnostics ->
     assertDiagnosticRanges diagnostics [(Range (Position 3 12) (Position 3 15), Just (InR "UndeclaredName"))]
 
 printUnknownCode :: Text
diff --git a/tests/app/Spec/Tests/Haskell/CodeActions.hs b/tests/app/Spec/Tests/Haskell/CodeActions.hs
index a185a62e..4450695b 100644
--- a/tests/app/Spec/Tests/Haskell/CodeActions.hs
+++ b/tests/app/Spec/Tests/Haskell/CodeActions.hs
@@ -8,6 +8,7 @@ import Data.Text
 import Language.LSP.Protocol.Lens hiding (actions)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Spec.Tests.Haskell.Common
 import Test.Sandwich as Sandwich
 import TestLib.LSP
@@ -17,13 +18,13 @@ import UnliftIO.Timeout
 
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> SpecFree context m ()
 tests ghcPackage = describe "Code actions" $ do
-  it "gets no code actions for putStrLn" $ doNotebookSession lsName codeActionsCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "gets no code actions for putStrLn" $ doNotebookSession lsName codeActionsCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     actions <- timeout 60_000_000 $ getCodeActions ident (Range (Position 1 0) (Position 1 8))
     actions `shouldBe` (Just [])
 
-  it "gets code actions for foo" $ doNotebookSession lsName codeActionsCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "gets code actions for foo" $ doNotebookSession lsName codeActionsCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     actions <- timeout 60_000_000 $ getCodeActions ident (Range (Position 0 0) (Position 0 3))
     case ghcPackage of
       x | x `L.elem` ["ghc910", "ghc912"] -> actions `shouldBe` (Just []) -- TODO: figure out why this is
diff --git a/tests/app/Spec/Tests/Haskell/Diagnostics.hs b/tests/app/Spec/Tests/Haskell/Diagnostics.hs
index 26619d52..90870612 100644
--- a/tests/app/Spec/Tests/Haskell/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Haskell/Diagnostics.hs
@@ -27,18 +27,18 @@ import TestLib.Types
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> Text -> SpecFree context m ()
 tests ghcPackage lsName = describe "Diagnostics" $ do
   describe "Foo.hs" $ do
-    testDiagnosticsLabelDesired "Out of scope variable" lsName "Foo.hs"
+    testDiagnosticsLabelDesired "Out of scope variable" lsName "Foo.hs" LanguageKind_Haskell
       [__i|module Foo where
            foo = bar
           |]
       ((== [(Range (Position 1 6) (Position 1 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabelDesired "Eta reduce" lsName "Foo.hs" etaExpandCode
+      testDiagnosticsLabelDesired "Eta reduce" lsName "Foo.hs" LanguageKind_Haskell etaExpandCode
         ((== [(Range (Position 6 0) (Position 6 14), Just (InR "refact:Eta reduce"))]) . getDiagnosticRanges)
 
   describe "main.ipynb" $ do
-    testDiagnosticsLabelDesired "Top-level putStrLn" lsName "main.ipynb"
+    testDiagnosticsLabelDesired "Top-level putStrLn" lsName "main.ipynb" LanguageKind_Haskell
       [__i|-- A comment
            foo = bar
 
@@ -46,7 +46,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
           |]
       ((== [(Range (Position 1 6) (Position 1 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
-    testDiagnosticsLabel "Top-level putStrLn with diagnostic" lsName "main.ipynb"
+    testDiagnosticsLabel "Top-level putStrLn with diagnostic" lsName "main.ipynb" LanguageKind_Haskell
       [__i|-- Some comment
            import Data.ByteString.Lazy.Char8 as BL
            foo = bar
@@ -56,7 +56,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
         [(Range (Position 4 0) (Position 4 8), x)] | containsAll x ["Ambiguous occurrence", "putStrLn"] -> return ()
         xs -> expectationFailure [i|Unexpected diagnostics: #{xs}|]
 
-    testDiagnosticsLabelDesired "Reordering" lsName "main.ipynb"
+    testDiagnosticsLabelDesired "Reordering" lsName "main.ipynb" LanguageKind_Haskell
       [__i|import Data.Aeson.TH
            {-\# LANGUAGE TemplateHaskell \#-}
            foo = bar -- This should be the only diagnostic we get
@@ -64,7 +64,7 @@ tests ghcPackage lsName = describe "Diagnostics" $ do
            $(deriveJSON defaultOptions ''Foo)|]
       ((== [(Range (Position 2 6) (Position 2 9), Just (InR "GHC-88464"))]) . getDiagnosticRanges)
 
-    testDiagnosticsLabelDesired "Complicated reordering" lsName "main.ipynb"
+    testDiagnosticsLabelDesired "Complicated reordering" lsName "main.ipynb" LanguageKind_Haskell
       [__i|import Data.Aeson as A
            import Data.Aeson.TH
            :set -XTemplateHaskell
diff --git a/tests/app/Spec/Tests/Haskell/DocumentHighlight.hs b/tests/app/Spec/Tests/Haskell/DocumentHighlight.hs
index 678e32fa..47bf0480 100644
--- a/tests/app/Spec/Tests/Haskell/DocumentHighlight.hs
+++ b/tests/app/Spec/Tests/Haskell/DocumentHighlight.hs
@@ -10,6 +10,7 @@ import Data.String.Interpolate
 import Data.Text as T
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Spec.Tests.Haskell.Common
 import Test.Sandwich as Sandwich
 import TestLib.LSP
@@ -18,12 +19,12 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Document highlight" $ do
-  it "foo (.ipynb)" $ doNotebookSession lsName documentHighlightCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "foo (.ipynb)" $ doNotebookSession lsName documentHighlightCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     getHighlights ident (Position 0 1) >>= (`shouldBe` documentHighlightResults)
 
-  it "foo (.hs)" $ doSession' "Test.hs" lsName documentHighlightCodeRegular $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "foo (.hs)" $ doSession' "Test.hs" lsName documentHighlightCodeRegular $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     getHighlights ident (Position 0 1) >>= (
       `shouldBe`  [
           DocumentHighlight (Range (Position 0 0) (Position 0 3)) (Just DocumentHighlightKind_Write)
diff --git a/tests/app/Spec/Tests/Haskell/Hover.hs b/tests/app/Spec/Tests/Haskell/Hover.hs
index 52e0bce4..848b4447 100644
--- a/tests/app/Spec/Tests/Haskell/Hover.hs
+++ b/tests/app/Spec/Tests/Haskell/Hover.hs
@@ -8,6 +8,7 @@ import Data.Text as T
 import Language.LSP.Protocol.Lens hiding (hover)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Spec.Tests.Haskell.Common
 import Test.Sandwich as Sandwich
 import TestLib.LSP
@@ -16,14 +17,14 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Hover" $ do
-  it "hovers foo" $ doNotebookSession lsName hoverCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "hovers foo" $ doNotebookSession lsName hoverCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     hover <- getHoverOrException ident (Position 0 1)
     allHoverText hover `textShouldContain` [i|foo|]
     allHoverText hover `textShouldContain` [i|main.ipynb.hs:1:1|]
 
-  it "hovers putStrLn" $ doNotebookSession lsName hoverCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "hovers putStrLn" $ doNotebookSession lsName hoverCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     hover <- getHoverOrException ident (Position 1 1)
     (hover ^. range) `shouldBe` Just (Range (Position 1 0) (Position 1 8))
     let InL (MarkupContent {..}) = hover ^. contents
diff --git a/tests/app/Spec/Tests/Haskell/Statements.hs b/tests/app/Spec/Tests/Haskell/Statements.hs
index c75522e2..02419e7d 100644
--- a/tests/app/Spec/Tests/Haskell/Statements.hs
+++ b/tests/app/Spec/Tests/Haskell/Statements.hs
@@ -6,6 +6,7 @@ import Data.String.Interpolate
 import Data.Text as T
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Spec.Tests.Haskell.Common
 import Spec.Tests.Haskell.DocumentHighlight (documentHighlightResults)
 import Test.Sandwich as Sandwich
@@ -17,23 +18,23 @@ import UnliftIO.Timeout
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> SpecFree context m ()
 tests ghcPackage = describe "Statements" $ do
   describe "Single-line" $ do
-    it "doesn't choke" $ doNotebookSession lsName statementsCode $ \filename -> do
-      ident <- openDoc filename "haskell"
+    it "doesn't choke" $ doNotebookSession lsName statementsCode $ \(Helpers.LspSessionInfo {..}) -> do
+      ident <- openDoc lspSessionInfoFileName "haskell"
       timeout 120_000_000 (getHighlights ident (Position 0 1)) >>= (`shouldBe` (Just documentHighlightResults))
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabel "Empty diagnostics" lsName "main.ipynb" statementsCode $ \diagnostics -> do
+      testDiagnosticsLabel "Empty diagnostics" lsName "main.ipynb" LanguageKind_Haskell statementsCode $ \diagnostics -> do
         -- Note: normally the server wouldn't send empty diagnostics. But the statement inserts "= unsafePerformIO $ ",
         -- which causes it to emit a "redundant bracket" diagnostic, which then gets filtered out by untransformPosition
         diagnostics `shouldBe` []
 
   describe "Multi-line" $ do
-    it "doesn't choke" $ doNotebookSession lsName statementsCode $ \filename -> do
-      ident <- openDoc filename "haskell"
+    it "doesn't choke" $ doNotebookSession lsName statementsCode $ \(Helpers.LspSessionInfo {..}) -> do
+      ident <- openDoc lspSessionInfoFileName "haskell"
       timeout 120_000_000 (getHighlights ident (Position 0 1)) >>= (`shouldBe` (Just documentHighlightResults))
 
     when (ghcPackage /= "ghc910") $ -- TODO: re-enable hlint test
-      testDiagnosticsLabel "Redundant bracket" lsName "main.ipynb" statementsCodeMultiline $ \diagnostics -> do
+      testDiagnosticsLabel "Redundant bracket" lsName "main.ipynb" LanguageKind_Haskell statementsCodeMultiline $ \diagnostics -> do
         info [i|Got diagnostics: #{diagnostics}|]
         assertDiagnosticRanges diagnostics [(Range (Position 1 9) (Position 1 14), Just (InR "refact:Redundant bracket"))]
 
diff --git a/tests/app/Spec/Tests/Haskell/Symbols.hs b/tests/app/Spec/Tests/Haskell/Symbols.hs
index 495c2c38..27acdcc9 100644
--- a/tests/app/Spec/Tests/Haskell/Symbols.hs
+++ b/tests/app/Spec/Tests/Haskell/Symbols.hs
@@ -4,6 +4,7 @@ module Spec.Tests.Haskell.Symbols (tests) where
 import Control.Lens ((^.))
 import Language.LSP.Protocol.Lens hiding (actions)
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Spec.Tests.Haskell.Common
 import Spec.Tests.Haskell.DocumentHighlight (documentHighlightCode)
 import Test.Sandwich as Sandwich
@@ -14,7 +15,7 @@ import UnliftIO.Timeout
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Symbols" $ do
-  it "symbols" $ doNotebookSession lsName documentHighlightCode $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it "symbols" $ doNotebookSession lsName documentHighlightCode $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
     Just (Right documentSymbols) <- timeout 300_000_000 $ getDocumentSymbols ident
     fmap (^. name) documentSymbols `shouldBe` ["foo"]
diff --git a/tests/app/Spec/Tests/Julia.hs b/tests/app/Spec/Tests/Julia.hs
index a5b780c0..74486431 100644
--- a/tests/app/Spec/Tests/Julia.hs
+++ b/tests/app/Spec/Tests/Julia.hs
@@ -10,6 +10,7 @@ import Data.Text as T
 import Language.LSP.Protocol.Lens hiding (diagnostics, hover, text)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Test.Sandwich as Sandwich
 import TestLib.JupyterRunnerContext
 import TestLib.LSP
@@ -45,12 +46,12 @@ juliaTests juliaPackage = describe [i|Julia (#{juliaPackage})|] $ introduceNixEn
   describe "LSP" $ do
     Diagnostics.tests lsName
 
-    itHasHoverSatisfying lsName "test.jl" [__i|print("hi")|] (Position 0 2) $ \hover -> do
+    itHasHoverSatisfying lsName "test.jl" (LanguageKind_Custom "julia") [__i|print("hi")|] (Position 0 2) $ \hover -> do
       let InL (MarkupContent MarkupKind_Markdown text) = hover ^. contents
       text `textShouldContain` "Write to `io` (or to the default output stream"
 
-    it "highlights foo" $ doNotebookSession lsName documentHighlightCode $ \filename -> do
-      ident <- openDoc filename "julia"
+    it "highlights foo" $ doNotebookSession lsName documentHighlightCode $ \(Helpers.LspSessionInfo {..}) -> do
+      ident <- openDoc lspSessionInfoFileName "julia"
       getHighlights ident (Position 0 1) >>= (`shouldBe` documentHighlightResults)
 
 
diff --git a/tests/app/Spec/Tests/Julia/Diagnostics.hs b/tests/app/Spec/Tests/Julia/Diagnostics.hs
index 60410eb8..d50df5da 100644
--- a/tests/app/Spec/Tests/Julia/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Julia/Diagnostics.hs
@@ -13,10 +13,10 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => Text -> SpecFree context m ()
 tests lsName = describe "Diagnostics" $ do
-  testDiagnostics'' "flags a simple missing reference" lsName "test.jl" [i|printlnzzzz("HI")|] [] $ \diagnostics -> do
+  testDiagnostics'' "flags a simple missing reference" lsName "test.jl" (LanguageKind_Custom "julia") [i|printlnzzzz("HI")|] [] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [(Range (Position 0 0) (Position 0 11), Nothing, "Missing reference: printlnzzzz")]
 
-  testDiagnosticsLabelDesired "finds symbols from JSON3 package" lsName "test.jl"
+  testDiagnosticsLabelDesired "finds symbols from JSON3 package" lsName "test.jl" (LanguageKind_Custom "julia")
     [__i|using JSON3: write
          tup = (:car,"Mercedes","S500",5,250.1)
          write(tup)
@@ -24,7 +24,7 @@ tests lsName = describe "Diagnostics" $ do
          |]
     ((== [(Range (Position 3 0) (Position 3 11), Nothing, "Missing reference: printlnzzzz")]) . getDiagnosticRanges')
 
-  testDiagnosticsLabelDesired "finds symbols from Roots package" lsName "test.jl"
+  testDiagnosticsLabelDesired "finds symbols from Roots package" lsName "test.jl" (LanguageKind_Custom "julia")
     [__i|using Roots: Bisection, find_zero
          f(x) = exp(x) - x^4
          find_zero(f, (8, 9), Bisection())
@@ -34,7 +34,7 @@ tests lsName = describe "Diagnostics" $ do
 
   -- This test is tricky because symbols like "plot" actually come from RecipesBase (or something), so
   -- it checks we're indexing such a transitive dependency.
-  testDiagnosticsLabelDesired "finds symbols from Plots package" lsName "test.jl"
+  testDiagnosticsLabelDesired "finds symbols from Plots package" lsName "test.jl" (LanguageKind_Custom "julia")
     [__i|using Plots: plot, plot!
          xx = range(0, 10, length=100)
          y = sin.(xx)
diff --git a/tests/app/Spec/Tests/Python.hs b/tests/app/Spec/Tests/Python.hs
index 66345543..5b15e8f6 100644
--- a/tests/app/Spec/Tests/Python.hs
+++ b/tests/app/Spec/Tests/Python.hs
@@ -35,21 +35,21 @@ tests' (kernelName, pythonPackage) = introduceNixEnvironment [kernelSpec kernelN
   testKernelStdout "python3" [i|print(42)|] "42\n"
   testKernelStdout' "python3" [i|import scipy|] Nothing
 
-  testDiagnostics "python-lsp-server" "test.py" [i|\n\n\nfoo = 42|] $ \diagnostics -> do
+  testDiagnostics "python-lsp-server" "test.py" LanguageKind_Python [i|\n\n\nfoo = 42|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "pylint" "test.py" [i|\n\n\nfoo = 42|] $ \diagnostics -> do
+  testDiagnostics "pylint" "test.py" LanguageKind_Python [i|\n\n\nfoo = 42|] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [
       (Range (Position 3 0) (Position 3 0), Nothing, "Final newline missing (C0304:missing-final-newline)")
       , (Range (Position 0 0) (Position 0 0), Nothing, "Missing module docstring (C0114:missing-module-docstring)")
       , (Range (Position 3 0) (Position 3 0), Nothing, "Disallowed name \"foo\" (C0104:disallowed-name)")
       ]
 
-  testDiagnostics "pyright" "test.py" [__i|\# pyright: strict
-                                                   def f(x: int, y: str) -> None:
-                                                     z = 1.0
-                                                   f("asdf", 42)
-                                                  |] $ \diagnostics -> do
+  testDiagnostics "pyright" "test.py" LanguageKind_Python [__i|\# pyright: strict
+                                                               def f(x: int, y: str) -> None:
+                                                                 z = 1.0
+                                                               f("asdf", 42)
+                                                              |] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [
       (Range (Position 3 2) (Position 3 8), Just (InR "reportArgumentType"), "Argument of type \"Literal['asdf']\" cannot be assigned to parameter \"x\" of type \"int\" in function \"f\"\n\160\160\"Literal['asdf']\" is not assignable to \"int\"")
       , (Range (Position 3 10) (Position 3 12), Just (InR "reportArgumentType"), "Argument of type \"Literal[42]\" cannot be assigned to parameter \"y\" of type \"str\" in function \"f\"\n\160\160\"Literal[42]\" is not assignable to \"str\"")
@@ -61,10 +61,10 @@ tests' (kernelName, pythonPackage) = introduceNixEnvironment [kernelSpec kernelN
       , (Range (Position 2 2) (Position 2 3), Just (InR "reportUnusedVariable"), "Variable \"z\" is not accessed")
       ]
 
-  testDiagnostics "pycodestyle" "test.py" [__i|def f(x: int, y: str) -> None:
-                                                 z = 1.0
-                                               f("asdf", 42)
-                                              |] $ \diagnostics -> do
+  testDiagnostics "pycodestyle" "test.py" LanguageKind_Python [__i|def f(x: int, y: str) -> None:
+                                                                     z = 1.0
+                                                                   f("asdf", 42)
+                                                                  |] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
 
diff --git a/tests/app/Spec/Tests/Ruby.hs b/tests/app/Spec/Tests/Ruby.hs
index af5f57f1..ec6dd56b 100644
--- a/tests/app/Spec/Tests/Ruby.hs
+++ b/tests/app/Spec/Tests/Ruby.hs
@@ -49,7 +49,7 @@ kernelTests rubyPackage = do
             info [i|RUBY_VERSION result: #{t}|]
             t `textShouldContain` versionString
 
-    itHasHoverSatisfying "solargraph" "test.rb" [__i|puts "hi"|] (Position 0 2) $ \hover -> do
+    itHasHoverSatisfying "solargraph" "test.rb" (LanguageKind_Ruby) [__i|puts "hi"|] (Position 0 2) $ \hover -> do
       let InL (MarkupContent MarkupKind_Markdown text) = hover ^. contents
       text `textShouldContain` "Kernel#puts"
       text `textShouldContain` "$stdout.puts(obj"
diff --git a/tests/app/Spec/Tests/Rust/Changes.hs b/tests/app/Spec/Tests/Rust/Changes.hs
index beccf27d..94fd253b 100644
--- a/tests/app/Spec/Tests/Rust/Changes.hs
+++ b/tests/app/Spec/Tests/Rust/Changes.hs
@@ -9,6 +9,7 @@ import Data.String.Interpolate
 import qualified Language.LSP.Protocol.Lens as LSP
 import Language.LSP.Protocol.Types
 import Language.LSP.Test
+import qualified Language.LSP.Test.Helpers as Helpers
 import Test.Sandwich as Sandwich
 import Test.Sandwich.Waits (waitUntil)
 import TestLib.LSP
@@ -17,8 +18,8 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Changes" $ do
-  it [i|Simple change|] $ doSession' "main.ipynb" "rust-analyzer" [i|println("hi");|] $ \filename -> do
-    ident <- openDoc filename "haskell"
+  it [i|Simple change|] $ doSession' "main.ipynb" "rust-analyzer" [i|println("hi");|] $ \(Helpers.LspSessionInfo {..}) -> do
+    ident <- openDoc lspSessionInfoFileName "haskell"
 
     waitUntil 120.0 $ do
       waitForDiagnostics >>= \diags -> do
diff --git a/tests/app/Spec/Tests/Rust/Completion.hs b/tests/app/Spec/Tests/Rust/Completion.hs
index 93a483ef..da5c9eb9 100644
--- a/tests/app/Spec/Tests/Rust/Completion.hs
+++ b/tests/app/Spec/Tests/Rust/Completion.hs
@@ -7,6 +7,7 @@ import Data.String.Interpolate
 import Language.LSP.Protocol.Lens hiding (edit, item, range)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test
+import qualified Language.LSP.Test.Helpers as Helpers
 import Safe
 import Test.Sandwich as Sandwich
 import Test.Sandwich.Waits (waitUntil)
@@ -17,8 +18,8 @@ import TestLib.Types
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Completions" $ do
   forM_ ["main.ipynb", "test.rs"] $ \doc -> do
-    it [i|(#{doc}) Completes printl to println!|] $ doSession' doc "rust-analyzer" [i|printl|] $ \filename -> do
-      ident <- openDoc filename "haskell"
+    it [i|(#{doc}) Completes printl to println!|] $ doSession' doc "rust-analyzer" [i|printl|] $ \(Helpers.LspSessionInfo {..}) -> do
+      ident <- openDoc lspSessionInfoFileName "haskell"
 
       waitUntil 60 $ do
         completions <- getCompletions ident (Position 0 6)
diff --git a/tests/app/Spec/Tests/Rust/Diagnostics.hs b/tests/app/Spec/Tests/Rust/Diagnostics.hs
index 1fbc1150..36df9e16 100644
--- a/tests/app/Spec/Tests/Rust/Diagnostics.hs
+++ b/tests/app/Spec/Tests/Rust/Diagnostics.hs
@@ -14,16 +14,15 @@ import TestLib.Types
 
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Diagnostics" $ do
-  testDiagnostics "rust-analyzer" "main.ipynb" [__i|printlnz!("Hello world");
-                                                   |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "main.ipynb" LanguageKind_Rust [__i|printlnz!("Hello world");\n|] $ \diagnostics -> do
     assertDiagnosticRanges' diagnostics [
       (Range (Position 0 0) (Position 0 8), Nothing, "cannot find macro `printlnz` in this scope")
       , (Range (Position 0 0) (Position 0 8), Nothing, "a macro with a similar name exists: `println`")
       ]
 
-  testDiagnostics "rust-analyzer" "test.rs" [__i|struct A { a: u8, b: u8 }
-                                                 const a: A = A { a: 10, };
-                                                |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "test.rs" LanguageKind_Rust [__i|struct A { a: u8, b: u8 }
+                                                                   const a: A = A { a: 10, };
+                                                                  |] $ \diagnostics -> do
     assertDiagnosticRanges' (L.sortBy (compare `on` (^. LSP.message)) diagnostics) [
       (Range (Position 1 13) (Position 1 14), Just (InR "E0063"), "missing field `b` in initializer of `A`\nmissing `b`")
       -- (Range (Position 1 6) (Position 1 7), Just (InR "non_upper_case_globals"), "Constant `a` should have UPPER_SNAKE_CASE name, e.g. `A`")
@@ -31,10 +30,10 @@ tests = describe "Diagnostics" $ do
       -- , (Range (Position 1 13) (Position 1 14), Just (InR "E0063"), "missing structure fields:\n- b\n")
       ]
 
-  testDiagnostics "rust-analyzer" "main.ipynb" [__i|println!("Hello world");
-                                                    eprintln!("Hello error");
-                                                    format!("Hello {}", "world")
-                                                   |] $ \diagnostics -> do
+  testDiagnostics "rust-analyzer" "main.ipynb" LanguageKind_Rust [__i|println!("Hello world");
+                                                                      eprintln!("Hello error");
+                                                                      format!("Hello {}", "world")
+                                                                     |] $ \diagnostics -> do
     assertDiagnosticRanges' (L.sortBy (compare `on` (^. LSP.message)) diagnostics) [
       (Range (Position 2 0) (Position 2 28), Just (InR "E0308"), "mismatched types\nexpected `()`, found `String`")
       ]
diff --git a/tests/app/Spec/Tests/Rust/Hovers.hs b/tests/app/Spec/Tests/Rust/Hovers.hs
index 3bc5d2e2..b9ef13d5 100644
--- a/tests/app/Spec/Tests/Rust/Hovers.hs
+++ b/tests/app/Spec/Tests/Rust/Hovers.hs
@@ -6,6 +6,7 @@ import Control.Monad.IO.Unlift
 import Data.String.Interpolate
 import Language.LSP.Protocol.Types
 import Language.LSP.Test
+import qualified Language.LSP.Test.Helpers as Helpers
 import Test.Sandwich as Sandwich
 import Test.Sandwich.Waits (waitUntil)
 import TestLib.LSP
@@ -16,8 +17,8 @@ import UnliftIO.Exception
 tests :: (LspContext context m, HasNixEnvironment context) => SpecFree context m ()
 tests = describe "Hovers" $ do
   forM_ ["main.ipynb", "test.rs"] $ \doc -> do
-    it [i|hovers println! (#{doc})|] $ doSession' doc "rust-analyzer" [i|println!("hi")|] $ \filename -> do
-      ident <- openDoc filename "haskell"
+    it [i|hovers println! (#{doc})|] $ doSession' doc "rust-analyzer" [i|println!("hi")|] $ \(Helpers.LspSessionInfo {..}) -> do
+      ident <- openDoc lspSessionInfoFileName "haskell"
 
       waitUntil 60 $
         handle handleSessionException' $ do
diff --git a/tests/app/Spec/Tests/Spellchecker.hs b/tests/app/Spec/Tests/Spellchecker.hs
index 034a836b..92a3db50 100644
--- a/tests/app/Spec/Tests/Spellchecker.hs
+++ b/tests/app/Spec/Tests/Spellchecker.hs
@@ -11,6 +11,7 @@ import Data.Text.IO as T
 import Language.LSP.Protocol.Lens hiding (actions, diagnostics, executeCommand, id)
 import Language.LSP.Protocol.Types
 import Language.LSP.Test hiding (message)
+import qualified Language.LSP.Test.Helpers as Helpers
 import Safe
 import System.FilePath
 import Test.Sandwich as Sandwich
@@ -29,7 +30,7 @@ otherConfig = [
 tests :: TopSpec
 tests = describe "Spellchecker" $ introduceNixEnvironment [] otherConfig "Spellchecker env" $ introduceJustBubblewrap $ do
   it "Gets diagnostics and a working code action" $ do
-    doSession'' "test.md" "spellchecker" [i|\# This is mispelled|] [] $ \lspHomeDir -> do
+    doSession'' "test.md" "spellchecker" [i|\# This is mispelled|] [] $ \(Helpers.LspSessionInfo {..}) -> do
       ident <- openDoc "test.md" "spellchecker"
       waitUntil 300.0 $ do
         diagnostics <- waitForDiagnostics
@@ -44,7 +45,7 @@ tests = describe "Spellchecker" $ introduceNixEnvironment [] otherConfig "Spellc
         Just (InR ca) -> executeCodeAction ca
 
       waitUntil 30 $ do
-        let datPath = lspHomeDir </> ".codedown/personal-dictionary.dat"
+        let datPath = lspSessionInfoHomeDir </> ".codedown/personal-dictionary.dat"
         doesFileExist datPath >>= (`shouldBe` True)
         liftIO (T.readFile datPath) >>= (`shouldBe` "mispelled\n")
 
@@ -56,7 +57,7 @@ tests = describe "Spellchecker" $ introduceNixEnvironment [] otherConfig "Spellc
         diagnostics <- waitForDiagnostics
         lift $ assertDiagnosticRanges diagnostics []
 
-  testDiagnostics "spellchecker" "test.md" [i|I've done a thing.|] $ \diagnostics -> do
+  testDiagnostics "spellchecker" "test.md" LanguageKind_Markdown [i|I've done a thing.|] $ \diagnostics -> do
     assertDiagnosticRanges diagnostics []
 
 
diff --git a/tests/app/Spec/Tests/Typst.hs b/tests/app/Spec/Tests/Typst.hs
index 2f4ebfad..2d41ae3b 100644
--- a/tests/app/Spec/Tests/Typst.hs
+++ b/tests/app/Spec/Tests/Typst.hs
@@ -35,7 +35,7 @@ tests = describe [i|Typst|] $ introduceNixEnvironment [] config [i|Typst|] $ int
     void $ testBuild [i|exporters.typst.packageSearch|]
 
   describe "LSP" $ do
-    testDiagnosticsLabelDesired "simple" lsName "test.typ"
+    testDiagnosticsLabelDesired "simple" lsName "test.typ" (LanguageKind_Custom "typst")
       [__i|\#loremz(45)|]
       ((== [(Range (Position 0 1) (Position 0 7), Nothing, "unknown variable: loremz")]) . getDiagnosticRanges')
 
diff --git a/tests/package.yaml b/tests/package.yaml
index be4f2100..792e7486 100644
--- a/tests/package.yaml
+++ b/tests/package.yaml
@@ -36,6 +36,7 @@ dependencies:
 - filepath
 - lens
 - lsp-test
+- lsp-test-helpers
 - lsp-types
 - monad-control
 - mtl
@@ -55,13 +56,10 @@ library:
   - bytestring
   - conduit
   - conduit-aeson
-  - data-default
   - directory
   - monad-logger
   - postgresql-simple
-  - row-types
   - template-haskell
-  - temporary
   - unliftio
   - unliftio-core
   - uri-encode
@@ -77,7 +75,6 @@ executables:
     build-tools: sandwich:sandwich-discover
     dependencies:
     - monad-logger
-    - row-types
     - tests
     - unliftio
     - unliftio-core
diff --git a/tests/src/TestLib/LSP.hs b/tests/src/TestLib/LSP.hs
index c314a30c..5ec063eb 100644
--- a/tests/src/TestLib/LSP.hs
+++ b/tests/src/TestLib/LSP.hs
@@ -37,7 +37,6 @@ import Control.Monad.Reader
 import Data.Aeson as A
 import qualified Data.ByteString as B
 import qualified Data.List as L
-import Data.Maybe
 import Data.String.Interpolate
 import qualified Data.Text as T hiding (filter)
 import Data.Text hiding (filter, show)
@@ -58,100 +57,100 @@ import UnliftIO.Process
 
 doNotebookSession :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> Text -> (FilePath -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
+  ) => Text -> Text -> (Helpers.LspSessionInfo -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
 doNotebookSession = doSession' "main.ipynb"
 
 doSession' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> Text -> Text -> (FilePath -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
+  ) => Text -> Text -> Text -> (Helpers.LspSessionInfo -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
 doSession' filename lsName codeToUse cb = doSession'' filename lsName codeToUse [] cb
 
 doSession'' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> Text -> Text -> [(FilePath, B.ByteString)] -> (FilePath -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
+  ) => Text -> Text -> Text -> [(FilePath, B.ByteString)] -> (Helpers.LspSessionInfo -> Session (ExampleT ctx m) a) -> ExampleT ctx m a
 doSession'' filename lsName codeToUse extraFiles cb = do
   lspConfig <- findLspConfig lsName
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
   let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
         lspSessionOptionsInitialFileName = T.unpack filename
+        , lspSessionOptionsInitialLanguageKind = LanguageKind_Python
         , lspSessionOptionsInitialCode = codeToUse
         , lspSessionOptionsExtraFiles = extraFiles
         , lspSessionOptionsReadOnlyBinds = closure
         , lspSessionOptionsPathEnvVar = pathToUse
         }
-  withLspSession lspSessionOptions $ \_homeDir -> do
-    cb (T.unpack filename)
+  withLspSession lspSessionOptions cb
 
 testDiagnostics :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics name filename code = testDiagnostics' name filename code []
+  ) => Text -> FilePath -> LanguageKind -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics name filename languageKind code = testDiagnostics' name filename languageKind code []
 
 testDiagnostics' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics' name filename codeToTest = testDiagnostics'' [i|#{name}, #{filename} with #{show codeToTest} (diagnostics)|] name filename codeToTest
+  ) => Text -> FilePath -> LanguageKind -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics' name filename languageKind codeToTest = testDiagnostics'' [i|#{name}, #{filename} with #{show codeToTest} (diagnostics)|] name filename languageKind codeToTest
 
 testDiagnosticsLabel :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnosticsLabel label name filename codeToTest = testDiagnostics'' label name filename codeToTest []
+  ) => String -> Text -> FilePath -> LanguageKind -> Text -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnosticsLabel label name filename languageKind codeToTest = testDiagnostics'' label name filename languageKind codeToTest []
 
 testDiagnosticsLabelDesired :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath -> Text -> ([Diagnostic] -> Bool) -> SpecFree ctx m ()
-testDiagnosticsLabelDesired label name filename code cb = it label $ do
+  ) => String -> Text -> FilePath -> LanguageKind -> Text -> ([Diagnostic] -> Bool) -> SpecFree ctx m ()
+testDiagnosticsLabelDesired label name filename languageKind code cb = it label $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
   let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
         lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialLanguageKind = languageKind
         , lspSessionOptionsInitialCode = code
         , lspSessionOptionsReadOnlyBinds = closure
         , lspSessionOptionsPathEnvVar = pathToUse
         }
 
-  Helpers.testDiagnostics lspSessionOptions $ \diags ->
-    if | cb diags -> return True
+  Helpers.testDiagnostics lspSessionOptions languageKind $ \diags ->
+    if | cb diags -> return ()
        | otherwise -> expectationFailure [i|Got unexpected diagnostics: #{diags}|]
 
-
 testDiagnostics'' :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => String -> Text -> FilePath-> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
-testDiagnostics'' label name filename code extraFiles cb = it label $ do
+  ) => String -> Text -> FilePath -> LanguageKind -> Text -> [(FilePath, B.ByteString)] -> ([Diagnostic] -> ExampleT ctx m ()) -> SpecFree ctx m ()
+testDiagnostics'' label name filename languageKind code extraFiles cb = it label $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
   let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
         lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialLanguageKind = languageKind
         , lspSessionOptionsInitialCode = code
         , lspSessionOptionsReadOnlyBinds = closure
         , lspSessionOptionsPathEnvVar = pathToUse
         , lspSessionOptionsExtraFiles = extraFiles
         }
 
-  Helpers.testDiagnostics lspSessionOptions $ \diags -> do
+  Helpers.testDiagnostics lspSessionOptions languageKind $ \diags -> do
     lift $ cb diags
-    return True
-
 
 itHasHoverSatisfying :: (
   LspContext ctx m, HasNixEnvironment ctx
-  ) => Text -> FilePath -> Text -> Position -> (Hover -> ExampleT ctx m ()) -> SpecFree ctx m ()
-itHasHoverSatisfying name filename code pos cb = it [i|#{name}: #{show code} (hover)|] $ do
+  ) => Text -> FilePath -> LanguageKind -> Text -> Position -> (Hover -> ExampleT ctx m ()) -> SpecFree ctx m ()
+itHasHoverSatisfying name filename languageKind code pos cb = it [i|#{name}: #{show code} (hover)|] $ do
   lspConfig <- findLspConfig name
   (pathToUse, closure) <- getPathAndNixEnvironmentClosure
 
   let lspSessionOptions = (defaultLspSessionOptions lspConfig) {
         lspSessionOptionsInitialFileName = filename
+        , lspSessionOptionsInitialLanguageKind = languageKind
         , lspSessionOptionsInitialCode = code
         , lspSessionOptionsReadOnlyBinds = closure
         , lspSessionOptionsPathEnvVar = pathToUse
         }
 
   withLspSession lspSessionOptions $ \_ -> do
-    ident <- openDoc filename (fromMaybe (LanguageKind_Custom "unknown") (lspConfigLanguageId lspConfig))
+    ident <- openDoc filename languageKind
     getHover ident pos >>= \case
       Nothing -> expectationFailure [i|Expected a hover.|]
       Just x -> lift $ cb x
@@ -201,27 +200,18 @@ getPathAndNixEnvironmentClosure = do
   return (pathToUse, closure)
 
 assertDiagnosticRanges :: (HasCallStack, MonadIO m) => [Diagnostic] -> [(Range, Maybe (Int32 |? Text))] -> ExampleT ctx m ()
-assertDiagnosticRanges diagnostics desired = if
-  | found == desired -> return ()
-  | otherwise ->
-      expectationFailure [__i|Got wrong diagnostics!
-
-                              Expected: #{A.encode desired}
-
-                              Found: #{A.encode found}
-                             |]
-  where
-    found = Helpers.getDiagnosticRanges diagnostics
+assertDiagnosticRanges = assertDiagnosticRanges'' Helpers.getDiagnosticRanges
 
 assertDiagnosticRanges' :: (HasCallStack, MonadIO m) => [Diagnostic] -> [(Range, Maybe (Int32 |? Text), Text)] -> m ()
-assertDiagnosticRanges' diagnostics desired = if
-  | found == desired -> return ()
+assertDiagnosticRanges' = assertDiagnosticRanges'' Helpers.getDiagnosticRanges'
+
+assertDiagnosticRanges'' :: (HasCallStack, MonadIO m, Eq a, ToJSON a) => ([Diagnostic] -> [a]) -> [Diagnostic] -> [a] -> m ()
+assertDiagnosticRanges'' keyFn diagnostics desired = if
+  | keyFn diagnostics == desired -> return ()
   | otherwise ->
       expectationFailure [__i|Got wrong diagnostics!
 
                               Expected: #{A.encode desired}
 
-                              Found: #{A.encode found}
+                              Found: #{A.encode $ keyFn diagnostics}
                              |]
-  where
-    found = Helpers.getDiagnosticRanges' diagnostics
diff --git a/tests/stack.yaml b/tests/stack.yaml
index df0651f1..5f4160e9 100644
--- a/tests/stack.yaml
+++ b/tests/stack.yaml
@@ -21,9 +21,6 @@ extra-deps:
 
 - git: https://github.com/codedownio/lsp-test-helpers.git
   # main branch
-  commit: 10a74a28168b56428ab7c465d8e25e4d9e4e4734
+  commit: 6a73e2393a1d9f21719580ce9ca0efbefabda60f
 
 - ex-pool-0.2.1@sha256:c8249338ced27bc4d6395ad9c3069eec394fb111813d6ec736814d095f7e6a24,1293
-
-- git: https://github.com/codedownio/minio-hs
-  commit: 768665c90321d118fdd3cde2c6ac6c01310d76a0
diff --git a/tests/stack.yaml.lock b/tests/stack.yaml.lock
index 6ccde934..c7f5cda9 100644
--- a/tests/stack.yaml.lock
+++ b/tests/stack.yaml.lock
@@ -43,6 +43,17 @@ packages:
     commit: d920b28aa25d454812d8d9bbd922e893574d45bc
     git: https://github.com/codedownio/lsp.git
     subdir: lsp-types
+- completed:
+    commit: 6a73e2393a1d9f21719580ce9ca0efbefabda60f
+    git: https://github.com/codedownio/lsp-test-helpers.git
+    name: lsp-test-helpers
+    pantry-tree:
+      sha256: d13e5237e21a6896422743aeee3f46019ca022e3e7d51b3b7196b9db9ec956c8
+      size: 1025
+    version: 0.1.0.0
+  original:
+    commit: 6a73e2393a1d9f21719580ce9ca0efbefabda60f
+    git: https://github.com/codedownio/lsp-test-helpers.git
 - completed:
     hackage: ex-pool-0.2.1@sha256:c8249338ced27bc4d6395ad9c3069eec394fb111813d6ec736814d095f7e6a24,1293
     pantry-tree:
@@ -50,17 +61,6 @@ packages:
       size: 253
   original:
     hackage: ex-pool-0.2.1@sha256:c8249338ced27bc4d6395ad9c3069eec394fb111813d6ec736814d095f7e6a24,1293
-- completed:
-    commit: 768665c90321d118fdd3cde2c6ac6c01310d76a0
-    git: https://github.com/codedownio/minio-hs
-    name: minio-hs
-    pantry-tree:
-      sha256: 63fecbf5146f8704eba62c12ba86494f7bc477d8d882e74846ea0d1dfce03a1a
-      size: 4744
-    version: 1.7.0
-  original:
-    commit: 768665c90321d118fdd3cde2c6ac6c01310d76a0
-    git: https://github.com/codedownio/minio-hs
 snapshots:
 - completed:
     sha256: 671a94f04c2cb37457b71c66134242d4b12ab703597c19fad769df2d5e1e5659
diff --git a/tests/tests.cabal b/tests/tests.cabal
index 94f408fe..6a155a39 100644
--- a/tests/tests.cabal
+++ b/tests/tests.cabal
@@ -59,25 +59,23 @@ library
     , conduit
     , conduit-aeson
     , containers
-    , data-default
     , directory
     , exceptions
     , filepath
     , lens
     , lsp-test
+    , lsp-test-helpers
     , lsp-types
     , monad-control
     , monad-logger
     , mtl
     , optparse-applicative
     , postgresql-simple
-    , row-types
     , safe
     , sandwich
     , sandwich-contexts
     , string-interpolate
     , template-haskell
-    , temporary
     , text
     , unliftio
     , unliftio-core
@@ -150,12 +148,12 @@ executable tests
     , filepath
     , lens
     , lsp-test
+    , lsp-test-helpers
     , lsp-types
     , monad-control
     , monad-logger
     , mtl
     , optparse-applicative
-    , row-types
     , safe
     , sandwich
     , sandwich-contexts

From ef973ee99874ad6338e4151995c7af2544c736bf Mon Sep 17 00:00:00 2001
From: Tom McLaughlin <tom@codedown.io>
Date: Sun, 11 Jan 2026 18:06:07 -0800
Subject: [PATCH 4/5] Rename basic-path

---
 tests/flake.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/flake.nix b/tests/flake.nix
index c42c2576..ea7d869e 100644
--- a/tests/flake.nix
+++ b/tests/flake.nix
@@ -34,7 +34,7 @@
 
             # Print a trivial PATH that we can use to run kernel and LSP tests, to ensure
             # they aren't depending on anything on the test machine's PATH.
-            print-basic-path = pkgs.writeShellScriptBin "codedown-artifact-sizes.sh" ''
+            print-basic-path = pkgs.writeShellScriptBin "basic-path.sh" ''
               echo ${pkgs.lib.makeBinPath (with pkgs; [coreutils bash])}
             '';
 

From 35c568b12cddcc39362eea4e4c58cb76151c0ef0 Mon Sep 17 00:00:00 2001
From: Tom McLaughlin <tom@codedown.io>
Date: Tue, 13 Jan 2026 16:41:46 -0800
Subject: [PATCH 5/5] ci: don't run on PR

---
 .github/workflows/ci.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cd35e2c1..6c32b844 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,7 +1,6 @@
 name: codedown-languages
 
 on:
-  pull_request:
   push:
   workflow_dispatch: