Mock HttpClient to avoid some proxy errors during running the pipeline

Author: onizet

Diff for: src/Html2OpenXml/IO/DefaultWebRequest.cs

@@ -126,7 +126,13 @@ public DefaultWebRequest(HttpClient httpClient, ILogger? logger = null)
             resource.StatusCode = response.StatusCode;
 
             if (response.IsSuccessStatusCode)
+            {
                 resource.Content = await response.Content.ReadAsStreamAsync().ConfigureAwait(false);
+                if (response.Content.Headers.TryGetValues("Content-Type", out var mime))
+                {
+                    resource.Headers.Add("Content-Type", string.Join(", ", mime));
+                }
+            }
 
             foreach (var header in response.Headers)
                 resource.Headers.Add(header.Key, string.Join(", ", header.Value));

Diff for: test/HtmlToOpenXml.Tests/ImgTests.cs

@@ -3,6 +3,8 @@
 using DocumentFormat.OpenXml.Packaging;
 using DocumentFormat.OpenXml.Wordprocessing;
 using Moq;
+using System.Net.Http;
+using System.Net.Http.Headers;
 
 namespace HtmlToOpenXml.Tests
 {
@@ -19,6 +21,16 @@ public class ImgTests : HtmlConverterTestBase
         [TestCase("https://upload.wikimedia.org/wikipedia/commons/b/b0/Mozilla_dinosaur_head_logo.svg", "image/svg+xml")]
         public async Task AbsoluteUri_ReturnsDrawing_WithDownloadedData(string imageUri, string contentType)
         {
+            var mockHttp = new MockHttpMessageHandler(uri => Task.FromResult(new HttpResponseMessage {
+                StatusCode = System.Net.HttpStatusCode.OK,
+                Content = new StreamContent(ResourceHelper.GetStream("Resources." + Path.GetFileName(imageUri))) { 
+                    Headers = { { "Content-Type", contentType } }
+                }
+            }));
+
+            var webRequest = new IO.DefaultWebRequest(new HttpClient(mockHttp));
+            converter = new HtmlConverter(mainPart, webRequest);
+
             await converter.ParseBody(
                 @$"<img src='{imageUri}' width='42' height='42'>",
                 TestContext.CurrentContext.CancellationToken);

Diff for: test/HtmlToOpenXml.Tests/Resources/Mozilla_dinosaur_head_logo.svg

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2017 Deal Stream sàrl. All rights reserved
+ */
+using System.Net.Http;
+
+namespace HtmlToOpenXml.Tests
+{
+    public class MockHttpMessageHandler : HttpMessageHandler
+    {
+        private readonly Func<Uri, Task<HttpResponseMessage>> _getResponseFunc;
+
+        public MockHttpMessageHandler(Func<Uri, Task<HttpResponseMessage>> getResponseFunc)
+        {
+            _getResponseFunc = getResponseFunc;
+        }
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            return await _getResponseFunc(request.RequestUri);
+        }
+    }
+}