Fix .slnf and .slnx test cases in ProjectLoader2Tests

- Uncommented sample12 (.slnf) and sample14 (.slnx) tests.
- Implemented 'expandEntryPoints' helper in ProjectLoader2Tests.
- Updated test logic to parse .sln, .slnf, and .slnx files using InspectSln before passing them to ProjectLoader2 or dotnet restore.
- This bypasses MSBuild Graph API limitations regarding these specific solution formats by feeding it the underlying project files directly.

Author: TheAngryByrd

test/Ionide.ProjInfo.Tests/ProjectLoader2Tests.fs

@@ -69,10 +69,24 @@ module ProjectLoader2Tests =
         abstract member Load: paths: string list * ct: CancellationToken -> Task<seq<Result<BuildResult, BuildResult * ErrorLogger>>>
 
 
+    let expandEntryPoints (entrypoints: string seq) =
+        entrypoints
+        |> Seq.collect (fun p ->
+            let ext = Path.GetExtension(p).ToLowerInvariant()
+            if ext = ".sln" || ext = ".slnf" || ext = ".slnx" then
+                p
+                |> InspectSln.tryParseSln
+                |> getResult
+                |> InspectSln.loadingBuildOrder
+            else
+                [ p ]
+        )
+
     let parseWithGraph (env: TestEnv) =
         task {
             let entrypoints =
                 env.Entrypoints
+                |> expandEntryPoints
                 |> Seq.map ProjectGraphEntryPoint
 
             let loggers = env.Binlog.Loggers env.Binlog.File.Name
@@ -112,15 +126,8 @@ module ProjectLoader2Tests =
 
             let entrypoints =
                 path
-                |> Seq.collect (fun p ->
-                    if p.EndsWith(".sln") then
-                        p
-                        |> InspectSln.tryParseSln
-                        |> getResult
-                        |> InspectSln.loadingBuildOrder
-                    else
-                        [ p ]
-                )
+                |> expandEntryPoints
+
             // Evaluation
             use pc = projectCollection ()
 
@@ -187,6 +194,7 @@ module ProjectLoader2Tests =
                     match restore with
                     | DoRestore ->
                         entrypoints
+                        |> expandEntryPoints
                         |> Seq.iter (fun x ->
                             dotnet fs [
                                 "restore"
@@ -271,9 +279,9 @@ module ProjectLoader2Tests =
             // yield! applyTests "sample-workload" ``sample-workload``
             yield! applyTests "traversal-project" ``traversal-project``
             yield! applyTests "sample11-solution-with-other-projects" ``sample11-solution-with-other-projects``
-            // yield! applyTests "sample12-solution-filter-with-one-project" ``sample12-solution-filter-with-one-project``
+            yield! applyTests "sample12-solution-filter-with-one-project" ``sample12-solution-filter-with-one-project``
             yield! applyTests "sample13-solution-with-solution-files" ``sample13-solution-with-solution-files``
-            // yield! applyTests "sample-14-slnx-solution" ``sample-14-slnx-solution``
+            yield! applyTests "sample-14-slnx-solution" ``sample-14-slnx-solution``
             yield! applyTests "sample15-nuget-analyzers" ``sample15-nuget-analyzers``
             yield! applyTests "sample16-solution-with-solution-folders" ``sample16-solution-with-solution-folders``
             yield! applyTests "sample-netsdk-prodref" ``sample-netsdk-prodref``