Add tests verifying ErrorMessage surfaces innermost exception message

alexeyzimarev · claude · alexeyzimarev · commit 5b1de23034be · 2026-02-26T16:24:20.000+01:00
Co-Authored-By: Claude Opus 4.6 &lt;noreply@anthropic.com&gt;
diff --git a/test/RestSharp.Tests/ErrorMessageTests.cs b/test/RestSharp.Tests/ErrorMessageTests.cs
@@ -0,0 +1,43 @@
+using System.Security.Authentication;
+
+namespace RestSharp.Tests;
+
+public class ErrorMessageTests {
+    [Fact]
+    public async Task ErrorMessage_surfaces_innermost_exception_message() {
+        const string innerMessage = "The remote certificate is invalid according to the validation procedure.";
+
+        var innerException = new AuthenticationException(innerMessage);
+        var wrappedException = new HttpRequestException("An error occurred while sending the request.", innerException);
+
+        var handler = new FakeHandler(wrappedException);
+        var client = new RestClient(new RestClientOptions("https://dummy.org") { ConfigureMessageHandler = _ => handler });
+
+        var response = await client.ExecuteAsync(new RestRequest("/"));
+
+        response.ErrorMessage.Should().Be(innerMessage);
+        response.ErrorException.Should().BeOfType<HttpRequestException>();
+        response.ErrorException!.InnerException.Should().BeOfType<AuthenticationException>();
+        response.ResponseStatus.Should().Be(ResponseStatus.Error);
+    }
+
+    [Fact]
+    public async Task ErrorMessage_uses_direct_message_when_no_inner_exception() {
+        const string message = "No such host is known.";
+
+        var exception = new HttpRequestException(message);
+        var handler = new FakeHandler(exception);
+        var client = new RestClient(new RestClientOptions("https://dummy.org") { ConfigureMessageHandler = _ => handler });
+
+        var response = await client.ExecuteAsync(new RestRequest("/"));
+
+        response.ErrorMessage.Should().Be(message);
+        response.ErrorException.Should().BeOfType<HttpRequestException>();
+        response.ErrorException!.InnerException.Should().BeNull();
+    }
+
+    class FakeHandler(Exception exception) : HttpMessageHandler {
+        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+            => throw exception;
+    }
+}
