Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/aspnetwebstack/test/Microsoft.TestCommon/CultureReplacer.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+
+using System.Globalization;
+using System.Threading;
+using Xunit;
+
+namespace System.Web.TestUtil
+{
+    public class CultureReplacer : IDisposable
+    {
+        private readonly CultureInfo _originalCulture;
+        private readonly long _threadId;
+
+        public CultureReplacer(string culture = "en-us")
+        {
+            _originalCulture = Thread.CurrentThread.CurrentCulture;
+            _threadId = Thread.CurrentThread.ManagedThreadId;
+            Thread.CurrentThread.CurrentCulture = CultureInfo.GetCultureInfo(culture);
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                Assert.True(Thread.CurrentThread.ManagedThreadId == _threadId, "The current thread is not the same as the thread invoking the constructor. This should never happen.");
+                Thread.CurrentThread.CurrentCulture = _originalCulture;
+            }
+        }
+    }
+}