PR review fixes

Author: darrelmiller

src/Microsoft.OpenApi.Readers/V2/OpenApiDocumentDeserializer.cs

@@ -137,7 +137,8 @@ private static void MakeServers(IList<OpenApiServer> servers, ParsingContext con
                 host = host ?? defaultUrl.GetComponents(UriComponents.NormalizedHost, UriFormat.SafeUnescaped);
                 basePath = basePath ?? defaultUrl.GetComponents(UriComponents.Path, UriFormat.SafeUnescaped);
                 schemes = schemes ?? new List<string> { defaultUrl.GetComponents(UriComponents.Scheme, UriFormat.SafeUnescaped) };
-            } else if (String.IsNullOrEmpty(host) && String.IsNullOrEmpty(basePath))
+            }
+            else if (String.IsNullOrEmpty(host) && String.IsNullOrEmpty(basePath))
             {
                 return;  // Can't make a server object out of just a Scheme
             }
@@ -147,6 +148,11 @@ private static void MakeServers(IList<OpenApiServer> servers, ParsingContext con
             {
                 foreach (var scheme in schemes)
                 {
+                    if (String.IsNullOrEmpty(scheme))
+                    {
+                        host = "//" + host;  // The double slash prefix creates a relative url where the scheme is defined by the BaseUrl
+                    }
+
                     var uriBuilder = new UriBuilder(scheme, host)
                     {
                         Path = basePath
@@ -164,7 +170,7 @@ private static void MakeServers(IList<OpenApiServer> servers, ParsingContext con
             {
                 if (!String.IsNullOrEmpty(host))
                 {
-                    host = "//" + host;
+                    host = "//" + host;  // The double slash prefix creates a relative url where the scheme is defined by the BaseUrl
                 }
                 var uriBuilder = new UriBuilder()
                 {

src/Microsoft.OpenApi/Extensions/OpenApiSerializableExtensions.cs

@@ -123,31 +123,7 @@ public static void Serialize<T>(this T element, IOpenApiWriter writer, OpenApiSp
         public static void Serialize<T>(this T element, IOpenApiWriter writer)
             where T : IOpenApiSerializable
         {
-            if (element == null)
-            {
-                throw Error.ArgumentNull(nameof(element));
-            }
-
-            if (writer == null)
-            {
-                throw Error.ArgumentNull(nameof(writer));
-            }
-
-            switch (writer.Settings.SpecVersion)
-            {
-                case OpenApiSpecVersion.OpenApi3_0:
-                    element.SerializeAsV3(writer);
-                    break;
-
-                case OpenApiSpecVersion.OpenApi2_0:
-                    element.SerializeAsV2(writer);
-                    break;
-
-                default:
-                    throw new OpenApiException(string.Format(SRResource.OpenApiSpecVersionNotSupported, writer.Settings.SpecVersion));
-            }
-
-            writer.Flush();
+            element.Serialize(writer, writer.Settings.SpecVersion);
         }
 
         /// <summary>