Attempt to remove watchman watch directories when enlistment is deleted

Scalar.FunctionalTests/Tools/ProcessHelper.cs

@@ -1,5 +1,8 @@
+using System;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices;
 
 namespace Scalar.FunctionalTests.Tools
 {
@@ -53,6 +56,45 @@ namespace Scalar.FunctionalTests.Tools
             }
         }
 
+        public static string GetProgramLocation(string processName)
+        {
+            ProcessResult result = ProcessHelper.Run(GetProgramLocator(), processName);
+            if (result.ExitCode != 0)
+            {
+                return null;
+            }
+
+            string firstPath =
+                string.IsNullOrWhiteSpace(result.Output)
+                ? null
+                : result.Output.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries).FirstOrDefault();
+            if (firstPath == null)
+            {
+                return null;
+            }
+
+            try
+            {
+                return Path.GetDirectoryName(firstPath);
+            }
+            catch (IOException)
+            {
+                return null;
+            }
+        }
+
+        private static string GetProgramLocator()
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return "where";
+            }
+            else
+            {
+                return "which";
+            }
+        }
+
         private static string StartProcess(Process executingProcess, Stream inputStream = null)
         {
             executingProcess.Start();

Scalar.FunctionalTests/Tools/ScalarFunctionalTestEnlistment.cs

@@ -122,6 +122,19 @@ namespace Scalar.FunctionalTests.Tools
 
         public void DeleteEnlistment()
         {
+            string watchmanLocation = ProcessHelper.GetProgramLocation("watchman");
+            if (!string.IsNullOrEmpty(watchmanLocation))
+            {
+                try
+                {
+                    ProcessHelper.Run(Path.Combine(watchmanLocation, "watchman"), $"watch-del {this.RepoRoot}");
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine($"Failed to delete watch on {this.RepoRoot}. {ex.ToString()}");
+                }
+            }
+
             TestResultsHelper.OutputScalarLogs(this);
             RepositoryHelpers.DeleteTestDirectory(this.EnlistmentRoot);
         }