From 5147f6db1d7cbeef38d42fd91706747bc25d93eb Mon Sep 17 00:00:00 2001
From: Adam Sitnik <adam.sitnik@gmail.com>
Date: Thu, 1 Apr 2021 11:37:10 +0200
Subject: [PATCH] use a hacky way to run all the tests using new FileStream
 implementation (which is currently disabled)

---
 Directory.Build.props                         |  1 +
 eng/runtimeconfig.template.json               |  5 +++
 .../Embedded/test/Net5CompatSwitchTests.cs    | 35 +++++++++++++++++++
 3 files changed, 41 insertions(+)
 create mode 100644 eng/runtimeconfig.template.json
 create mode 100644 src/FileProviders/Embedded/test/Net5CompatSwitchTests.cs

diff --git a/Directory.Build.props b/Directory.Build.props
index c837ed4c35d9..b8fbd0c931ff 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -220,6 +220,7 @@
 
     <ArchiveExtension>.tar.gz</ArchiveExtension>
     <ArchiveExtension Condition="'$(TargetOsName)' == 'win'">.zip</ArchiveExtension>
+    <UserRuntimeConfig Condition="'$(IsTestProject)' == 'true'">$(RepoRoot)eng\runtimeconfig.template.json</UserRuntimeConfig>
   </PropertyGroup>
 
   <Import Project="eng\Workarounds.props" />
diff --git a/eng/runtimeconfig.template.json b/eng/runtimeconfig.template.json
new file mode 100644
index 000000000000..0c1a3482aba4
--- /dev/null
+++ b/eng/runtimeconfig.template.json
@@ -0,0 +1,5 @@
+{
+    "configProperties": {
+        "System.IO.UseNet5CompatFileStream": false
+    }
+}
diff --git a/src/FileProviders/Embedded/test/Net5CompatSwitchTests.cs b/src/FileProviders/Embedded/test/Net5CompatSwitchTests.cs
new file mode 100644
index 000000000000..af9157b8e5c9
--- /dev/null
+++ b/src/FileProviders/Embedded/test/Net5CompatSwitchTests.cs
@@ -0,0 +1,35 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#if NET6_0
+using System.Reflection;
+using Xunit;
+
+namespace System.IO.Tests
+{
+    public class Net5CompatSwitchTests
+    {
+        [Fact]
+        public static void LegacySwitchIsHonored()
+        {
+            string filePath = Path.Combine(Path.GetTempPath(), Path.GetTempFileName());
+
+            using (FileStream fileStream = File.Create(filePath))
+            {
+                object strategy = fileStream
+                    .GetType()
+                    .GetField("_strategy", BindingFlags.NonPublic | BindingFlags.Instance)
+                    .GetValue(fileStream);
+
+                if (OperatingSystem.IsWindows())
+                {
+                    Assert.DoesNotContain("Net5Compat", strategy.GetType().FullName);
+                    Assert.DoesNotContain("Legacy", strategy.GetType().FullName);
+                }
+            }
+
+            File.Delete(filePath);
+        }
+    }
+}
+#endif