fix(core): 🐛 include API error code in exception messages

Author: PrzemyslawKlys

SectigoCertificateManager.Tests/ApiErrorHandlerTests.cs

@@ -105,4 +105,16 @@ public async Task ExceptionMessageTruncatesLongBody() {
         Assert.Contains(new string('a', 200), ex.Message);
         Assert.DoesNotContain(new string('a', 201), ex.Message);
     }
+
+    [Fact]
+    public async Task ExceptionMessageIncludesErrorCode() {
+        var response = new HttpResponseMessage(HttpStatusCode.BadRequest) {
+            Content = JsonContent.Create(new ApiError { Code = ApiErrorCode.ErrorWhileDecodingCsr, Description = "Invalid" })
+        };
+
+        using var client = CreateClient(response);
+
+        var ex = await Assert.ThrowsAsync<ValidationException>(() => client.GetAsync("v1/test"));
+        Assert.Contains($"Code: {(int)ApiErrorCode.ErrorWhileDecodingCsr}", ex.Message);
+    }
 }

SectigoCertificateManager/ApiErrorHandler.cs

@@ -5,8 +5,14 @@ namespace SectigoCertificateManager;
 using System.Net.Http;
 using System.Text.Json;
 using System.Threading;
-using System.Threading.Tasks;
-
+using System.Threading.Tasks;        if (!string.IsNullOrWhiteSpace(error.Description)) {
+            message += $", Error: {error.Description}";
+        }
+        if ((int)error.Code != 0) {
+            message += $", Code: {(int)error.Code}";
+        }
+
+        error.Description = message;
 /// <summary>
 /// Handles API error responses.
 /// </summary>