Add a setter for HttpContext.Current

src/Microsoft.AspNetCore.SystemWebAdapters/Generated/Ref.Standard.cs

@@ -138,7 +138,7 @@ internal HttpContext() { }
         public System.Web.HttpApplicationState Application { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
         public System.Web.HttpApplication ApplicationInstance { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
         public System.Web.Caching.Cache Cache { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
-        public static System.Web.HttpContext Current { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
+        public static System.Web.HttpContext Current { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} set { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
         public System.Web.RequestNotification CurrentNotification { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
         public System.Exception Error { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }
         public bool IsDebuggingEnabled { get { throw new System.PlatformNotSupportedException("Only supported when running on ASP.NET Core or System.Web");} }

src/Microsoft.AspNetCore.SystemWebAdapters/HttpContext.cs

@@ -28,7 +28,11 @@ public class HttpContext : IServiceProvider
     private IDictionary? _items;
     private TraceContext? _trace;
 
-    public static HttpContext? Current => _accessor.HttpContext;
+    public static HttpContext? Current
+    {
+        get => _accessor.HttpContext;
+        set => _accessor.HttpContext = value;
+    }
 
     internal HttpContext(HttpContextCore context)
     {

test/Microsoft.AspNetCore.SystemWebAdapters.Tests/HttpContextTests.cs

@@ -471,5 +471,34 @@ public void RewritePathWithPathInfo(bool rebase)
             // Assert
             feature.Verify(f => f.Rewrite(filePath, pathInfo, query, rebase), Times.Once);
         }
+
+        [Fact]
+        public void SetHttpContext()
+        {
+            // Arrange
+            var coreContext = new DefaultHttpContext();
+            var context = new HttpContext(coreContext);
+
+            // Act
+            HttpContext.Current = context;
+
+            // Assert
+            Assert.IsType<HttpContext>(HttpContext.Current);
+        }
+
+        [Fact]
+        public void SetHttpContextToNull()
+        {
+            // Arrange
+            var coreContext = new DefaultHttpContext();
+            var context = new HttpContext(coreContext);
+            HttpContext.Current = context;
+
+            // Act
+            HttpContext.Current = null;
+
+            // Assert
+            Assert.Null(HttpContext.Current);
+        }
     }
 }