Fix uri conversion and add some tests to prove its working

src/GraphQL.Client/UriExtensions.cs

@@ -9,7 +9,7 @@ public static class UriExtensions
         /// </summary>
         /// <param name="uri"></param>
         /// <returns></returns>
-        public static bool HasWebSocketScheme(this Uri uri) => uri.Scheme.Equals("wss") || uri.Scheme.Equals("ws");
+        public static bool HasWebSocketScheme(this Uri uri) => uri.Scheme.Equals("wss", StringComparison.OrdinalIgnoreCase) || uri.Scheme.Equals("ws", StringComparison.OrdinalIgnoreCase);
 
         /// <summary>
         /// Infers the websocket uri from <paramref name="uri"/>.
@@ -21,8 +21,16 @@ public static Uri GetWebSocketUri(this Uri uri)
             if (uri.HasWebSocketScheme())
                 return uri;
 
-            string webSocketScheme = uri.Scheme == "https" ? "wss" : "ws";
-            return new Uri($"{webSocketScheme}://{uri.Host}:{uri.Port}{uri.PathAndQuery}");
+            string webSocketScheme;
+
+            if (uri.Scheme == Uri.UriSchemeHttps)
+                webSocketScheme = "wss";
+            else if (uri.Scheme == Uri.UriSchemeHttp)
+                webSocketScheme = "ws";
+            else
+                throw new NotSupportedException($"cannot infer websocket uri from uri scheme {uri.Scheme}");
+
+            return new UriBuilder(uri){Scheme = webSocketScheme}.Uri;
         }
     }
 }

tests/GraphQL.Integration.Tests/UriExtensionTests.cs

@@ -0,0 +1,47 @@
+using System;
+using FluentAssertions;
+using GraphQL.Client.Http;
+using Xunit;
+
+namespace GraphQL.Integration.Tests
+{
+    public class UriExtensionTests
+    {
+        [Theory]
+        [InlineData("http://thats-not-a-websocket-url.net", false)]
+        [InlineData("https://thats-not-a-websocket-url.net", false)]
+        [InlineData("ftp://thats-not-a-websocket-url.net", false)]
+        [InlineData("ws://that-is-a-websocket-url.net", true)]
+        [InlineData("wss://that-is-a-websocket-url.net", true)]
+        [InlineData("WS://that-is-a-websocket-url.net", true)]
+        [InlineData("WSS://that-is-a-websocket-url.net", true)]
+        public void HasWebSocketSchemaTest(string url, bool result)
+        {
+            new Uri(url).HasWebSocketScheme().Should().Be(result);
+        }
+
+        [Theory]
+        [InlineData("http://this-url-can-be-converted.net", true, "ws://this-url-can-be-converted.net")]
+        [InlineData("https://this-url-can-be-converted.net", true, "wss://this-url-can-be-converted.net")]
+        [InlineData("HTTP://this-url-can-be-converted.net", true, "ws://this-url-can-be-converted.net")]
+        [InlineData("HTTPS://this-url-can-be-converted.net", true, "wss://this-url-can-be-converted.net")]
+        [InlineData("ws://this-url-can-be-converted.net", true, "ws://this-url-can-be-converted.net")]
+        [InlineData("wss://this-url-can-be-converted.net", true, "wss://this-url-can-be-converted.net")]
+        [InlineData("https://this-url-can-be-converted.net/and/all/elements/?are#preserved", true, "wss://this-url-can-be-converted.net/and/all/elements/?are#preserved")]
+        [InlineData("ftp://this-url-cannot-be-converted.net", false, null)]
+        // AppSync example
+        [InlineData("wss://example1234567890000.appsync-realtime-api.us-west-2.amazonaws.com/graphql?header=123456789ABCDEF&payload=e30=", true, "wss://example1234567890000.appsync-realtime-api.us-west-2.amazonaws.com/graphql?header=123456789ABCDEF&payload=e30=")]
+        public void GetWebSocketUriTest(string input, bool canConvert, string result)
+        {
+            var inputUri = new Uri(input);
+            if (canConvert)
+            {
+                inputUri.GetWebSocketUri().Should().BeEquivalentTo(new Uri(result));
+            }
+            else
+            {
+                inputUri.Invoking(uri => uri.GetWebSocketUri()).Should().Throw<NotSupportedException>();
+            }
+        }
+    }
+}