Support adding custom plaintext headers to downstream requests (#314)

test/Ocelot.UnitTests/Headers/AddHeadersToRequestPlainTests.cs

@@ -0,0 +1,75 @@
+using Microsoft.AspNetCore.Http;
+using Moq;
+using Ocelot.Configuration.Creator;
+using Ocelot.Headers;
+using Ocelot.Infrastructure.Claims.Parser;
+using Shouldly;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.UnitTests.Headers
+{
+    public class AddHeadersToRequestPlainTests
+    {
+        private readonly AddHeadersToRequest _addHeadersToRequest;
+        private HttpContext _context;
+        private AddHeader _addedHeader;
+
+        public AddHeadersToRequestPlainTests()
+        {
+            _addHeadersToRequest = new AddHeadersToRequest(Mock.Of<IClaimsParser>());
+        }
+
+        [Fact]
+        public void should_add_plain_text_header_to_downstream_request()
+        {
+            this.Given(_ => GivenHttpRequestWithoutHeaders())
+                .When(_ => WhenAddingHeader("X-Custom-Header", "PlainValue"))
+                .Then(_ => ThenTheHeaderGetsTakenOverToTheRequestHeaders())
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_overwrite_existing_header_with_added_header()
+        {
+            this.Given(_ => GivenHttpRequestWithHeader("X-Custom-Header", "This should get overwritten"))
+                .When(_ => WhenAddingHeader("X-Custom-Header", "PlainValue"))
+                .Then(_ => ThenTheHeaderGetsTakenOverToTheRequestHeaders())
+                .BDDfy();
+        }
+
+        private void GivenHttpRequestWithoutHeaders()
+        {
+            _context = new DefaultHttpContext();
+        }
+
+        private void GivenHttpRequestWithHeader(string headerKey, string headerValue)
+        {
+            _context = new DefaultHttpContext
+            {
+                Request =
+                {
+                    Headers =
+                    {
+                        { headerKey, headerValue }
+                    }
+                }
+            };
+        }
+
+        private void WhenAddingHeader(string headerKey, string headerValue)
+        {
+            _addedHeader = new AddHeader(headerKey, headerValue);
+            _addHeadersToRequest.SetHeadersOnDownstreamRequest(new[] { _addedHeader }, _context);
+        }
+        
+        private void ThenTheHeaderGetsTakenOverToTheRequestHeaders()
+        {
+            var requestHeaders = _context.Request.Headers;
+            requestHeaders.ContainsKey(_addedHeader.Key).ShouldBeTrue($"Header {_addedHeader.Key} was expected but not there.");
+            var value = requestHeaders[_addedHeader.Key];
+            value.ShouldNotBeNull($"Value of header {_addedHeader.Key} was expected to not be null.");
+            value.ToString().ShouldBe(_addedHeader.Value);
+        }
+    }
+}