use IDisposal for test clean up

Author: ahmelsayed

test/Azure.Functions.Cli.Tests/ActionsTests/StartHostActionTests.cs

@@ -16,7 +16,7 @@
 
 namespace Azure.Functions.Cli.Tests.ActionsTests
 {
-    public class StartHostActionTests
+    public class StartHostActionTests : IDisposable
     {
         [SkippableFact]
         public async Task CheckNonOptionalSettingsThrowsOnMissingAzureWebJobsStorage()
@@ -113,5 +113,10 @@ private IFileSystem GetFakeFileSystem(IEnumerable<(string folder, string functio
 
             return fileSystem;
         }
+
+        public void Dispose()
+        {
+            FileSystemHelpers.Instance = null;
+        }
     }
 }

test/Azure.Functions.Cli.Tests/E2E/Helpers/CliTester.cs

@@ -69,7 +69,7 @@ private static async Task InternalRun(string workingDir, RunConfiguration[] runC
                             }
                             else
                             {
-                                exitError &= (await exitCodeTask) != 1;
+                                exitError &= exitCodeTask.Result != 1;
                             }
                         }
                     }