Adds the possibility to simulate a timeout.

Author: dnperfors

README.md

@@ -9,6 +9,5 @@ The following assertions should be able in the first release:
 - WithContentType: Or headers in the body of a httprequestmessage
 
 Preferably the follwing setup for responses:
-- Simulate timeout
 - easier response body creation?
 

src/HttpClientTestHelpers/TestableHttpMessageHandler.cs

@@ -24,6 +24,11 @@ public class TestableHttpMessageHandler : HttpMessageHandler
         protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         {
             httpRequestMessages.Enqueue(request);
+
+            if(response is TimeoutHttpResponseMessage)
+            {
+                throw new TaskCanceledException(new OperationCanceledException().Message);
+            }
             return Task.FromResult(response);
         }
 
@@ -36,6 +41,14 @@ public void RespondWith(HttpResponseMessage httpResponseMessage)
             response = httpResponseMessage ?? throw new ArgumentNullException(nameof(httpResponseMessage));
         }
 
+        /// <summary>
+        /// Simulate a timeout on the request by throwing a TaskCanceledException when a request is received.
+        /// </summary>
+        public void SimulateTimeout()
+        {
+            response = new TimeoutHttpResponseMessage();
+        }
+
         /// <summary>
         /// Validates that requests have been made, throws an exception when no requests were made.
         /// </summary>
@@ -81,5 +94,9 @@ public HttpRequestMessageAsserter ShouldNotHaveMadeRequestsTo(string pattern)
 
             return new HttpRequestMessageAsserter(Requests, true).WithUriPattern(pattern);
         }
+
+        private class TimeoutHttpResponseMessage : HttpResponseMessage
+        {
+        }
     }
 }

test/HttpClientTestHelpers.Tests/TestableHttpMessageHandlerTests.cs

@@ -185,5 +185,16 @@ public void RespondWith_NullValue_ThrowsArgumentNullException()
             Assert.Equal("httpResponseMessage", exception.ParamName);
         }
 #nullable restore
+
+        [Fact]
+        public async Task SimulateTimout_WhenRequestIsMade_ThrowsTaskCancelationExceptionWithOperationCanceledMessage()
+        {
+            using var sut = new TestableHttpMessageHandler();
+            sut.SimulateTimeout();
+            using var client = new HttpClient(sut);
+
+            var exception = await Assert.ThrowsAsync<TaskCanceledException>(() => client.GetAsync("https://example.com"));
+            Assert.Equal(new OperationCanceledException().Message, exception.Message);
+        }
     }
 }