Centralize Visual Studio installation discovery and assembly resolution in test infrastructure

tests/FSharp.Test.Utilities/VSInstallDiscovery.fs

@@ -126,3 +126,11 @@ module VSInstallDiscovery =
         | NotFound reason -> 
             logAction $"Visual Studio installation not found: {reason}"
             None
+
+    /// Gets the VS installation directory or fails with a detailed error message.
+    /// This is the recommended method for test scenarios that require VS to be installed.
+    let getVSInstallDirOrFail () : string =
+        match tryFindVSInstallation () with
+        | Found (path, _) -> path
+        | NotFound reason -> 
+            failwith $"Visual Studio installation not found: {reason}. Ensure VS is installed or environment variables (VSAPPIDDIR, VS*COMNTOOLS) are set."

vsintegration/tests/FSharp.Editor.Tests/Helpers/AssemblyResolver.fs

@@ -10,24 +10,7 @@ module AssemblyResolver =
     open System.Globalization
     open FSharp.Test.VSInstallDiscovery
 
-    let vsInstallDir =
-        // Use centralized VS installation discovery with graceful fallback
-        match tryGetVSInstallDir () with
-        | Some dir -> dir
-        | None ->
-            // Fallback to legacy behavior for backward compatibility
-            let vsvar =
-                let var = Environment.GetEnvironmentVariable("VS170COMNTOOLS")
-
-                if String.IsNullOrEmpty var then
-                    Environment.GetEnvironmentVariable("VSAPPIDDIR")
-                else
-                    var
-
-            if String.IsNullOrEmpty vsvar then
-                failwith "VS170COMNTOOLS and VSAPPIDDIR environment variables not found."
-
-            Path.Combine(vsvar, "..")
+    let vsInstallDir = getVSInstallDirOrFail ()
 
     let probingPaths =
         [|
@@ -40,9 +23,9 @@ module AssemblyResolver =
         |]
 
     let addResolver () =
-        AppDomain.CurrentDomain.add_AssemblyResolve (fun h args ->
+        AppDomain.CurrentDomain.add_AssemblyResolve (fun _ args ->
             let found () =
-                (probingPaths)
+                probingPaths
                 |> Seq.tryPick (fun p ->
                     try
                         let name = AssemblyName(args.Name)
@@ -52,7 +35,7 @@ module AssemblyResolver =
                             name.CodeBase <- codebase
                             name.CultureInfo <- Unchecked.defaultof<CultureInfo>
                             name.Version <- Unchecked.defaultof<Version>
-                            Some(name)
+                            Some name
                         else
                             None
                     with _ ->

vsintegration/tests/Salsa/VsMocks.fs

@@ -1642,6 +1642,7 @@ module internal VsActual =
     open System.ComponentModel.Composition.Primitives
     open Microsoft.VisualStudio.Text
     open Microsoft.VisualStudio.Threading
+    open FSharp.Test.VSInstallDiscovery
 
     type TestExportJoinableTaskContext () =
 
@@ -1650,16 +1651,7 @@ module internal VsActual =
         [<System.ComponentModel.Composition.Export(typeof<JoinableTaskContext>)>]
         member public _.JoinableTaskContext : JoinableTaskContext = jtc
 
-    let vsInstallDir =
-        // use the environment variable to find the VS installdir
-        let vsvar =
-            let var = Environment.GetEnvironmentVariable("VS170COMNTOOLS")
-            if String.IsNullOrEmpty var then
-                Environment.GetEnvironmentVariable("VSAPPIDDIR")
-            else
-                var
-        if String.IsNullOrEmpty vsvar then failwith "VS170COMNTOOLS and VSAPPIDDIR environment variables not found."
-        Path.Combine(vsvar, "..")
+    let vsInstallDir = getVSInstallDirOrFail ()
 
     let CreateEditorCatalog() =
         let thisAssembly = Assembly.GetExecutingAssembly().Location

vsintegration/tests/UnitTests/AssemblyResolver.fs

@@ -8,45 +8,36 @@ module AssemblyResolver =
     open System.Globalization
     open FSharp.Test.VSInstallDiscovery
 
-    let vsInstallDir =
-        // Use centralized VS installation discovery with graceful fallback
-        match tryGetVSInstallDir () with
-        | Some dir -> dir
-        | None -> 
-            // Fallback to legacy behavior for backward compatibility
-            let vsvar =
-                let var = Environment.GetEnvironmentVariable("VS170COMNTOOLS")
-                if String.IsNullOrEmpty var then
-                    Environment.GetEnvironmentVariable("VSAPPIDDIR")
-                else
-                    var
-            if String.IsNullOrEmpty vsvar then failwith "VS170COMNTOOLS and VSAPPIDDIR environment variables not found."
-            Path.Combine(vsvar, "..")
+    let vsInstallDir = getVSInstallDirOrFail ()
 
-    let probingPaths = [|
-        Path.Combine(vsInstallDir, @"IDE\CommonExtensions\Microsoft\Editor")
-        Path.Combine(vsInstallDir, @"IDE\PublicAssemblies")
-        Path.Combine(vsInstallDir, @"IDE\PrivateAssemblies")
-        Path.Combine(vsInstallDir, @"IDE\CommonExtensions\Microsoft\ManagedLanguages\VBCSharp\LanguageServices")
-        Path.Combine(vsInstallDir, @"IDE\Extensions\Microsoft\CodeSense\Framework")
-        Path.Combine(vsInstallDir, @"IDE")
-    |]
+    let probingPaths =
+        [|
+            Path.Combine(vsInstallDir, @"IDE\CommonExtensions\Microsoft\Editor")
+            Path.Combine(vsInstallDir, @"IDE\PublicAssemblies")
+            Path.Combine(vsInstallDir, @"IDE\PrivateAssemblies")
+            Path.Combine(vsInstallDir, @"IDE\CommonExtensions\Microsoft\ManagedLanguages\VBCSharp\LanguageServices")
+            Path.Combine(vsInstallDir, @"IDE\Extensions\Microsoft\CodeSense\Framework")
+            Path.Combine(vsInstallDir, @"IDE")
+        |]
 
     let addResolver () =
-        AppDomain.CurrentDomain.add_AssemblyResolve(fun h args ->
+        AppDomain.CurrentDomain.add_AssemblyResolve(fun _ args ->
             let found () =
-                (probingPaths ) |> Seq.tryPick(fun p ->
+                probingPaths
+                |> Seq.tryPick (fun p ->
                     try
                         let name = AssemblyName(args.Name)
                         let codebase = Path.GetFullPath(Path.Combine(p, name.Name) + ".dll")
                         if File.Exists(codebase) then
                             name.CodeBase <- codebase
                             name.CultureInfo <- Unchecked.defaultof<CultureInfo>
                             name.Version <- Unchecked.defaultof<Version>
-                            Some (name)
-                        else None
-                    with | _ -> None
-                    )
-            match found() with
+                            Some name
+                        else
+                            None
+                    with _ ->
+                        None)
+
+            match found () with
             | None -> Unchecked.defaultof<Assembly>
-            | Some name -> Assembly.Load(name) )
+            | Some name -> Assembly.Load(name))