fix(deserialization): deserialize enums

fix exception thrown when attributes are of an enum type during
deserialization

Author: jasolko

src/JsonApiDotNetCore/Internal/TypeHelper.cs

@@ -22,6 +22,9 @@ public static object ConvertType(object value, Type type)
                 if (type == typeof(DateTimeOffset))
                     return DateTimeOffset.Parse(stringValue);
 
+                if (type.GetTypeInfo().IsEnum)
+                    return Enum.Parse(type, stringValue);
+
                 return Convert.ChangeType(stringValue, type);
             }
             catch (Exception e)

test/UnitTests/Internal/TypeHelper_Tests.cs

@@ -30,5 +30,23 @@ public void Bad_DateTimeOffset_String_Throws()
             // assert
             Assert.Throws<FormatException>(() => TypeHelper.ConvertType(formattedString, typeof(DateTimeOffset)));
         }
+
+        [Fact]
+        public void Can_Convert_Enums()
+        {
+            // arrange
+            var formattedString = "1";
+
+            // act
+            var result = TypeHelper.ConvertType(formattedString, typeof(TestEnum));
+
+            // assert
+            Assert.Equal(TestEnum.Test, result);
+        }
+
+        public enum TestEnum
+        {
+            Test = 1
+        }
     }
 }