Test Expect: 100-continue when body is not sent (#1038)

Fixes #617

test/ReverseProxy.Tests/Service/Proxy/HttpProxyTests.cs

@@ -1644,6 +1644,33 @@ namespace Yarp.ReverseProxy.Service.Proxy.Tests
                 destinationPrefix, httpClient, requestOptions, transforms));
         }
 
+        [Theory]
+        [InlineData("HTTP/1.1", "1.1")]
+        [InlineData("HTTP/2", "2.0")]
+        public async Task ProxyAsync_Expect100ContinueWithFailedResponse_ReturnResponse(string fromProtocol, string toProtocol)
+        {
+            var httpContext = new DefaultHttpContext();
+            httpContext.Request.Method = "GET";
+            httpContext.Request.Protocol = fromProtocol;
+            httpContext.Request.Headers[HeaderNames.Expect] = "100-continue";
+            using var contentStream = new MemoryStream(Encoding.UTF8.GetBytes(new string('a', 1024 * 1024 * 10)));
+            httpContext.Request.Body = contentStream;
+
+            var destinationPrefix = "https://localhost:123/a/b/";
+            var sut = CreateProxy();
+            var client = MockHttpHandler.CreateClient(
+                async (HttpRequestMessage request, CancellationToken cancellationToken) =>
+                {
+                    await Task.Yield();
+                    return new HttpResponseMessage(HttpStatusCode.Conflict);
+                });
+
+            await sut.ProxyAsync(httpContext, destinationPrefix, client, new RequestProxyConfig { Version = Version.Parse(toProtocol) });
+
+            Assert.Equal(0, contentStream.Position);
+            Assert.Equal((int)HttpStatusCode.Conflict, httpContext.Response.StatusCode);
+        }
+
         [Theory]
         [InlineData("1.1", false, "Connection: upgrade; Upgrade: test123", null, "Connection; Upgrade")]
         [InlineData("1.1", false, "Connection: keep-alive; Keep-Alive: timeout=100", null, "Connection; Keep-Alive")]

testassets/TestClient/Scenarios/Http2PostExpectContinueScenario.cs

@@ -11,10 +11,10 @@ using System.Threading.Tasks;
 namespace SampleClient.Scenarios
 {
     /// <summary>
-    /// Verifies that Island Gateway correctly handles the case where the client specifies
+    /// Verifies that YARP correctly handles the case where the client specifies
     /// <c>Expect: 100-continue</c> and the destination fails early without accepting the request body.
     /// This scenario can be encountered in real world scenarios, usually when authentication fails on the destination.
-    /// The <c>Expect: 100-continue</c> behavior causes the request body copy to not even start on Island Gateway in this case.
+    /// The <c>Expect: 100-continue</c> behavior causes the request body copy to not even start on YARP in this case.
     /// </summary>
     internal class Http2PostExpectContinueScenario : IScenario
     {