Refactor FakeHttpMessageHandler, minor changes to TestRequest and Htt…

…pRequestMessageExtensions

src/Tests/TransmissionManager.BaseTests/HttpClient/FakeHttpMessageHandler.cs

@@ -10,11 +10,21 @@ public FakeHttpMessageHandler(TestRequest testRequest, TestResponse testResponse
     {
     }
 
-    protected override Task<HttpResponseMessage> SendAsync(
+    protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)
+    {
+        return SendInternal(request.ToTestRequestAsync().GetAwaiter().GetResult());
+    }
+
+    protected override async Task<HttpResponseMessage> SendAsync(
         HttpRequestMessage request,
         CancellationToken cancellationToken)
     {
-        if (requestToResponseMap.TryGetValue(request.ToTestRequest(), out var testResponse))
+        return SendInternal(await request.ToTestRequestAsync().ConfigureAwait(false));
+    }
+
+    private HttpResponseMessage SendInternal(TestRequest testRequest)
+    {
+        if (requestToResponseMap.TryGetValue(testRequest, out var testResponse))
         {
             var response = new HttpResponseMessage
             {
@@ -26,9 +36,11 @@ protected override Task<HttpResponseMessage> SendAsync(
                 foreach (var (name, value) in testResponse.Headers)
                     response.Headers.TryAddWithoutValidation(name, value);
 
-            return Task.FromResult(response);
+            return response;
         }
 
-        return Task.FromResult(new HttpResponseMessage { StatusCode = (HttpStatusCode)418 });
+        // My hope here is that none of the faked endpoints are expected to return "418 I'm a teapot".
+        // This is done in order not to occupy an exception type which could be asserted in the tests.
+        return new() { StatusCode = (HttpStatusCode)418 };
     }
 }

src/Tests/TransmissionManager.BaseTests/HttpClient/HttpRequestMessageExtensions.cs

@@ -2,12 +2,12 @@
 
 internal static class HttpRequestMessageExtensions
 {
-    public static TestRequest ToTestRequest(this HttpRequestMessage requestMessage)
+    public static async Task<TestRequest> ToTestRequestAsync(this HttpRequestMessage request)
     {
-        return new TestRequest(
-            requestMessage.Method,
-            requestMessage.RequestUri,
-            requestMessage.Headers.ToDictionary(static pair => pair.Key, static pair => pair.Value.Single()),
-            requestMessage.Content?.ReadAsStringAsync().GetAwaiter().GetResult());
+        return new(
+            request.Method,
+            request.RequestUri,
+            request.Headers.ToDictionary(static pair => pair.Key, static pair => pair.Value.Single()),
+            request.Content is null ? null : await request.Content.ReadAsStringAsync().ConfigureAwait(false));
     }
 }

src/Tests/TransmissionManager.BaseTests/HttpClient/TestRequest.cs

@@ -3,7 +3,7 @@
 public sealed record TestRequest(
     HttpMethod Method,
     Uri? RequestUri,
-    Dictionary<string, string>? Headers = null,
+    IReadOnlyDictionary<string, string>? Headers = null,
     string? Content = null)
 {
     public bool Equals(TestRequest? other)