#280 Add headers to response (#286)

* #280 can now add response headers inc trace id, now need to consolidate the header place holder stuff

* #280 changed port for linux tests

* #280 lots of hacking around to handle errors and consolidate placeholders into one class

test/Ocelot.UnitTests/Infrastructure/PlaceholdersTests.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Net.Http;
+using Moq;
+using Ocelot.Infrastructure;
+using Ocelot.Infrastructure.RequestData;
+using Ocelot.Middleware;
+using Ocelot.Responses;
+using Shouldly;
+using Xunit;
+
+namespace Ocelot.UnitTests.Infrastructure
+{
+    public class PlaceholdersTests
+    {
+        private IPlaceholders _placeholders;
+        private Mock<IBaseUrlFinder> _finder;
+        private Mock<IRequestScopedDataRepository> _repo;
+        
+        public PlaceholdersTests()
+        {
+            _repo = new Mock<IRequestScopedDataRepository>();
+            _finder = new Mock<IBaseUrlFinder>();
+            _placeholders = new Placeholders(_finder.Object, _repo.Object);
+        }
+
+        [Fact]
+        public void should_return_base_url()
+        {
+            var baseUrl = "http://www.bbc.co.uk";
+            _finder.Setup(x => x.Find()).Returns(baseUrl);
+            var result = _placeholders.Get("{BaseUrl}");
+            result.Data.ShouldBe(baseUrl);
+        }
+
+        [Fact]
+        public void should_return_key_does_not_exist()
+        {
+            var result = _placeholders.Get("{Test}");
+            result.IsError.ShouldBeTrue();
+            result.Errors[0].Message.ShouldBe("Unable to find placeholder called {Test}");
+        }
+
+        [Fact]
+        public void should_return_downstream_base_url_when_port_is_not_80_or_443()
+        {
+            var request = new HttpRequestMessage();
+            request.RequestUri = new Uri("http://www.bbc.co.uk");
+            var result = _placeholders.Get("{DownstreamBaseUrl}", request);
+            result.Data.ShouldBe("http://www.bbc.co.uk/");
+        }
+
+
+        [Fact]
+        public void should_return_downstream_base_url_when_port_is_80_or_443()
+        {
+              var request = new HttpRequestMessage();
+            request.RequestUri = new Uri("http://www.bbc.co.uk:123");
+            var result = _placeholders.Get("{DownstreamBaseUrl}", request);
+            result.Data.ShouldBe("http://www.bbc.co.uk:123/");
+        }
+
+        [Fact]
+        public void should_return_key_does_not_exist_for_http_request_message()
+        {
+            var result = _placeholders.Get("{Test}", new System.Net.Http.HttpRequestMessage());
+            result.IsError.ShouldBeTrue();
+            result.Errors[0].Message.ShouldBe("Unable to find placeholder called {Test}");
+        }
+
+        [Fact]
+        public void should_return_trace_id()
+        {
+            var traceId = "123";
+            _repo.Setup(x => x.Get<string>("TraceId")).Returns(new OkResponse<string>(traceId));
+            var result = _placeholders.Get("{TraceId}");
+            result.Data.ShouldBe(traceId);
+        }
+    }
+}