Add tests to document that double escaping is allowed.

Author: Cesar Blum Silveira

test/Microsoft.AspNet.Server.WebListener.FunctionalTests/RequestTests.cs

@@ -140,6 +140,23 @@ public async Task Request_MalformedPathReturns400StatusCode(string requestPath)
             }
         }
 
+        [Fact]
+        public async Task Request_DoubleEscapingAllowed()
+        {
+            string root;
+            using (var server = Utilities.CreateHttpServerReturnRoot("/", out root, httpContext =>
+            {
+                var requestInfo = httpContext.Features.Get<IHttpRequestFeature>();
+                Assert.Equal("/%2F", requestInfo.Path);
+                return Task.FromResult(0);
+            }))
+            {
+                var response = await SendSocketRequestAsync(root, "/%252F");
+                var responseStatusCode = response.Substring(9); // Skip "HTTP/1.1 "
+                Assert.Equal("200", responseStatusCode);
+            }
+        }
+
         [Theory]
         // The test server defines these prefixes: "/", "/11", "/2/3", "/2", "/11/2"
         [InlineData("/", "", "/")]

test/Microsoft.Net.Http.Server.FunctionalTests/RequestTests.cs

@@ -100,6 +100,18 @@ public async Task Request_MalformedPathReturns400StatusCode(string requestPath)
             }
         }
 
+        [Fact]
+        public async Task Request_DoubleEscapingAllowed()
+        {
+            string root;
+            using (var server = Utilities.CreateHttpServerReturnRoot("/", out root))
+            {
+                var responseTask = SendSocketRequestAsync(root, "/%252F");
+                var context = await server.GetContextAsync();
+                Assert.Equal("/%2F", context.Request.Path);
+            }
+        }
+
         [Theory]
         // The test server defines these prefixes: "/", "/11", "/2/3", "/2", "/11/2"
         [InlineData("/", "", "/")]