Create and throw dedicated serialization exception. fix #274

Author: robsiera

arangodb-net-standard.Test/CursorApi/CursorApiClientTest.cs

@@ -2,9 +2,14 @@
 using ArangoDBNetStandard.CursorApi;
 using ArangoDBNetStandard.CursorApi.Models;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Net;
+using System.Text;
 using System.Threading.Tasks;
+using ArangoDBNetStandard.Serialization;
+using ArangoDBNetStandard.Transport;
+using Moq;
 using Xunit;
 
 namespace ArangoDBNetStandardTest.CursorApi
@@ -159,6 +164,55 @@ public async Task PostCursorAsync_ShouldThrow_WhenAqlIsNotValid()
             Assert.Equal(1203, ex.ApiError.ErrorNum);
         }
 
+        [Fact]
+        public async Task PostCursorAsync_ShouldThrow_WhenErrorDeserializationFailed()
+        {
+            var mockTransport = new Mock<IApiClientTransport>();
+
+            var mockResponse = new Mock<IApiClientResponse>();
+
+            var mockResponseContent = new Mock<IApiClientResponseContent>();
+
+            string mockJsonError = "{ errorNum: \"some_error\" }";
+
+            mockResponseContent.Setup(x => x.ReadAsStreamAsync())
+                .Returns(Task.FromResult<Stream>(
+                    new MemoryStream(Encoding.UTF8.GetBytes(mockJsonError))));
+
+            mockResponse.Setup(x => x.Content)
+                .Returns(mockResponseContent.Object);
+
+            mockResponse.Setup(x => x.IsSuccessStatusCode)
+                .Returns(false);
+
+            mockTransport.Setup(x => x.PostAsync(
+                    It.IsAny<string>(),
+                    It.IsAny<byte[]>()))
+                .Returns(Task.FromResult(mockResponse.Object));
+
+            var cursorApi = new CursorApiClient(mockTransport.Object);
+
+            var ex = await Assert.ThrowsAsync<SerializationException>(async () =>
+            {
+                await cursorApi.PostCursorAsync<object>("RETURN true");
+            });
+
+            Assert.NotNull(ex.Message);
+            Assert.NotNull(ex.InnerException);
+        }
+
+        [Fact]
+        public async Task PostCursorAsync_ShouldThrowException_WhenResponseDeserializationFailed()
+        {
+            var ex = await Assert.ThrowsAsync<SerializationException>(async () =>
+            {
+                await _cursorApi.PostCursorAsync<int>("RETURN null");
+            });
+
+            Assert.NotNull(ex.Message);
+            Assert.NotNull(ex.InnerException);
+        }
+
         [Fact]
         public async Task PutCursorAsync_ShouldSucceed()
         {

arangodb-net-standard/ApiClientBase.cs

@@ -28,8 +28,15 @@ public ApiClientBase(IApiClientSerialization serialization)
         protected async Task<ApiErrorException> GetApiErrorException(IApiClientResponse response)
         {
             var stream = await response.Content.ReadAsStreamAsync();
-            var error = _serialization.DeserializeFromStream<ApiErrorResponse>(stream);
-            return new ApiErrorException(error);
+            try
+            {
+                var error = _serialization.DeserializeFromStream<ApiErrorResponse>(stream);
+                return new ApiErrorException(error);
+            }
+            catch (Exception e)
+            {
+                throw new SerializationException($"An error occured while Deserializing an error response from Arango. See InnerException for more details.", e);
+            }
         }
 
         protected void ValidateDocumentId(string documentId)
@@ -43,15 +50,29 @@ protected void ValidateDocumentId(string documentId)
 
         protected T DeserializeJsonFromStream<T>(Stream stream)
         {
-            return _serialization.DeserializeFromStream<T>(stream);
+            try
+            {
+                return _serialization.DeserializeFromStream<T>(stream);
+            }
+            catch (Exception e)
+            {
+                throw new SerializationException($"An error occured while Deserializing the data response from Arango. See InnerException for more details.", e);
+            }
         }
 
         protected byte[] GetContent<T>(T item, bool useCamelCasePropertyNames, bool ignoreNullValues)
         {
-            return _serialization.Serialize<T>(
-                item,
-                useCamelCasePropertyNames,
-                ignoreNullValues);
+            try
+            {
+                return _serialization.Serialize<T>(
+                    item,
+                    useCamelCasePropertyNames,
+                    ignoreNullValues);
+            }
+            catch (Exception e)
+            {
+                throw new SerializationException($"A serialization error occured while preparing a request for Arango. See InnerException for more details.", e);
+            }
         }
     }
 }

arangodb-net-standard/Serialization/SerializationException.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace ArangoDBNetStandard.Serialization
+{
+    [Serializable]
+    public class SerializationException : Exception
+    {
+        public SerializationException(string message, Exception innerException) : base(message, innerException)
+        {
+        }
+    }
+}