fix(type-helper): do not silently return default

something unexpected happened, we should return an error

Author: jaredcnance

src/JsonApiDotNetCore/Internal/TypeHelper.cs

@@ -24,12 +24,9 @@ public static object ConvertType(object value, Type type)
 
                 return Convert.ChangeType(stringValue, type);
             }
-            catch (Exception)
+            catch (Exception e)
             {
-                if (type.GetTypeInfo().IsValueType)
-                    return Activator.CreateInstance(type);
-
-                return null;
+                throw new FormatException($"{ value } cannot be converted to { type.GetTypeInfo().Name }", e);
             }
         }
     }

test/UnitTests/Internal/TypeHelper_Tests.cs

@@ -19,5 +19,16 @@ public void Can_Convert_DateTimeOffsets()
             // assert
             Assert.Equal(dto, result);
         }
+
+        [Fact]
+        public void Bad_DateTimeOffset_String_Throws()
+        {
+            // arrange
+            var formattedString = "this_is_not_a_valid_dto";
+
+            // act
+            // assert
+            Assert.Throws<FormatException>(() => TypeHelper.ConvertType(formattedString, typeof(DateTimeOffset)));
+        }
     }
 }