http error code tests and docs

Author: TomPallister

docs/features/errorcodes.rst

@@ -0,0 +1,13 @@
+Http Error Status Codes
+=======================
+
+Ocelot will return HTTP status error codes based on internal logic in certain siturations:
+- 401 if the authentication middleware runs and the user is not authenticated.
+- 403 if the authorisation middleware runs and the user is unauthenticated, claim value not authroised, scope not authorised, user doesnt have required claim or cannot find claim.
+- 503 if the downstream request times out.
+- 499 if the request is cancelled by the client.
+- 404 if unable to find a downstream route.
+- 502 if unable to connect to downstream service.
+- 500 if unable to complete the HTTP request downstream and the exception is not OperationCanceledException or HttpRequestException.
+- 404 if Ocelot is unable to map an internal error code to a HTTP status code.
+

docs/index.rst

@@ -42,6 +42,7 @@ Thanks for taking a look at the Ocelot documentation. Please use the left hand n
    features/loadbalancer
    features/delegatinghandlers
    features/raft
+   features/errorcodes
 
 .. toctree::
    :maxdepth: 2

src/Ocelot/Requester/ConnectionToDownstreamServiceError.cs

@@ -3,7 +3,7 @@
 
 namespace Ocelot.Requester
 {
-    class ConnectionToDownstreamServiceError : Error
+    public class ConnectionToDownstreamServiceError : Error
     {
         public ConnectionToDownstreamServiceError(Exception exception)
             : base($"Error connecting to downstream service, exception: {exception}", OcelotErrorCode.ConnectionToDownstreamServiceError)

src/Ocelot/Requester/HttpExeptionToErrorMapper.cs

@@ -5,7 +5,6 @@ namespace Ocelot.Requester
     using System;
     using System.Collections.Generic;
     using System.Net.Http;
-    using System.Net.Sockets;
 
     public class HttpExeptionToErrorMapper : IExceptionToErrorMapper
     {

src/Ocelot/Responder/IErrorsToHttpStatusCodeMapper.cs

@@ -1,8 +1,9 @@
-using Ocelot.Errors;
-using System.Collections.Generic;
+namespace Ocelot.Responder
+{
+    using System.Net;
+    using Ocelot.Errors;
+    using System.Collections.Generic;
 
-namespace Ocelot.Responder
-{
     /// <summary>
     /// Map a list OceoltErrors to a single appropriate HTTP status code
     /// </summary>

test/Ocelot.UnitTests/Requester/HttpExeptionToErrorMapperTests.cs

@@ -7,6 +7,7 @@
     using Shouldly;
     using System;
     using System.Collections.Generic;
+    using System.Net.Http;
     using System.Threading.Tasks;
     using Xunit;
 
@@ -38,6 +39,14 @@ public void should_return_request_canceled()
             error.ShouldBeOfType<RequestCanceledError>();
         }
 
+        [Fact]
+        public void should_return_ConnectionToDownstreamServiceError()
+        {
+            var error = _mapper.Map(new HttpRequestException());
+
+            error.ShouldBeOfType<ConnectionToDownstreamServiceError>();
+        }
+
         [Fact]
         public void should_return_request_canceled_for_subtype()
         {