addressing feedback

test/NuGet.Core.FuncTests/NuGet.Packaging.CrossVerify.Generate.Test/GenerateSignedPackages.cs

@@ -16,7 +16,7 @@ namespace NuGet.Packaging.CrossVerify.Generate.Test
     public class GenerateSignedPackages
     {
         private readonly GenerateFixture _generateFixture;
-        private string _directoryPath;
+        private readonly string _directoryPath;
 
         private readonly SigningTestFixture _signingTestFixture_Author;
         private readonly TrustedTestCert<TestCertificate> _authorSignningCert;
@@ -396,6 +396,8 @@ public async Task PreGenerateSignedPackages_AuthorSigned_TimeStampedWithNoSignin
                         nupkg,
                         packagePath,
                         timestampService.Url);
+
+                    Assert.True(File.Exists(signedPackagePath));
                 }
             }
         }

test/NuGet.Core.FuncTests/NuGet.Packaging.CrossVerify.Verify.Test/VerifySignedPackages.cs

@@ -358,7 +358,7 @@ public async Task VerifySignaturesAsync_PreGenerateSignedPackages_AuthorSigned_T
             string caseName = TestPackages.Package1.ToString();
 
             var signedPackageFolder = Path.Combine(dir, caseName, "package");
-            var signedPackagePath = TestFileSystemUtility.GetFirstFileName(signedPackageFolder, "*.nupkg");
+            var signedPackagePath = TestFileSystemUtility.GetFirstFileNameOrNull(signedPackageFolder, "*.nupkg");
 
             using (FileStream stream = File.OpenRead(signedPackagePath))
             using (var reader = new PackageArchiveReader(stream))

test/TestUtilities/Test.Utility/Signing/TestPackages.cs

@@ -1,12 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
 namespace Test.Utility.Signing
 {
     /// <summary>

test/TestUtilities/Test.Utility/TestFileSystemUtility.cs

@@ -95,7 +95,7 @@ private static DirectoryInfo GetRepositoryRoot(DirectoryInfo currentDir)
         /// <param name="path"></param>
         /// <param name="searchPattern"><see cref="System.IO.Directory.EnumerateFiles(string, string)"/></param>
         /// <returns></returns>
-        public static string GetFirstFileName(string path, string searchPattern)
+        public static string GetFirstFileNameOrNull(string path, string searchPattern)
         {
             IEnumerable<string> files = Directory.EnumerateFiles(path, searchPattern);