Moved exception messages to resource file and updated tests to validate exception messages

src/Microsoft.AspNet.JsonPatch/Adapters/ObjectAdapter.cs

@@ -157,21 +157,19 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
                         }
                         else
                         {
-                            throw new JsonPatchException<T>(operationToReport,
+                            throw new JsonPatchException<T>(
-                                string.Format("Patch failed: provided path is invalid for array property type at " +
+                                operationToReport,
-                                    "location path: {0}: position larger than array size",
+                                Resources.FormatInvalidIndexForArrayProperty(operationToReport.op, path),
-                                    path, 422),
                                 objectToApplyTo);
                         }
                     }
                 }
                 else
                 {
-                    throw new JsonPatchException<T>(operationToReport,
+                    throw new JsonPatchException<T>(
-                       string.Format("Patch failed: provided path is invalid for array property type at location " +
+                        operationToReport,
-                            "path: {0}: expected array",
+                        Resources.FormatInvalidPathForArrayProperty(operationToReport.op, path),
-                            path),
+                        objectToApplyTo);
-                       objectToApplyTo, 422);
                 }
             }
             else
@@ -247,22 +245,20 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
 
                     if (array.Count <= positionAsInteger)
                     {
-                        throw new JsonPatchException<T>(operation,
+                        throw new JsonPatchException<T>(
-                            string.Format("Patch failed: provided from path is invalid for array property type at " +
+                            operation,
-                                "location from: {0}: invalid position",
+                            Resources.FormatInvalidIndexForArrayProperty(operation.op, operation.from),
-                                operation.from),
+                            objectToApplyTo);
-                            objectToApplyTo, 422);
                     }
 
                     valueAtFromLocation = array[positionAsInteger];
                 }
                 else
                 {
-                    throw new JsonPatchException<T>(operation,
+                    throw new JsonPatchException<T>(
-                       string.Format("Patch failed: provided from path is invalid for array property type at " +
+                        operation,
-                            "location from: {0}: expected array",
+                        Resources.FormatInvalidPathForArrayProperty(operation.op, operation.from),
-                            operation.from),
+                        objectToApplyTo);
-                       objectToApplyTo, 422);
                 }
             }
             else
@@ -356,21 +352,19 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
                         }
                         else
                         {
-                            throw new JsonPatchException<T>(operationToReport,
+                            throw new JsonPatchException<T>(
-                                string.Format("Patch failed: provided path is invalid for array property type at " +
+                                operationToReport,
-                                    "location path: {0}: position larger than array size",
+                                Resources.FormatInvalidIndexForArrayProperty(operationToReport.op, path),
-                                    path),
+                                objectToApplyTo);
-                                objectToApplyTo, 422);
                         }
                     }
                 }
                 else
                 {
-                    throw new JsonPatchException<T>(operationToReport,
+                    throw new JsonPatchException<T>(
-                       string.Format("Patch failed: provided path is invalid for array property type at " +
+                        operationToReport,
-                            "location path: {0}: expected array",
+                        Resources.FormatInvalidPathForArrayProperty(operationToReport.op, path),
-                            path),
+                        objectToApplyTo);
-                       objectToApplyTo, 422);
                 }
             }
             else
@@ -477,22 +471,20 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
 
                     if (array.Count <= positionInPathAsInteger)
                     {
-                        throw new JsonPatchException<T>(operation,
+                        throw new JsonPatchException<T>(
-                            string.Format("Patch failed: provided from path is invalid for array property type at " +
+                            operation,
-                                "location path: {0}: invalid position",
+                            Resources.FormatInvalidIndexForArrayProperty(operation.op, operation.path),
-                                operation.path),
+                            objectToApplyTo);
-                            objectToApplyTo, 422);
                     }
 
                     valueAtPathLocation = array[positionInPathAsInteger];
                 }
                 else
                 {
-                    throw new JsonPatchException<T>(operation,
+                    throw new JsonPatchException<T>(
-                       string.Format("Patch failed: provided from path is invalid for array property type at " +
+                        operation,
-                            "location path: {0}: expected array",
+                        Resources.FormatInvalidPathForArrayProperty(operation.op, operation.path),
-                            operation.path),
+                        objectToApplyTo);
-                       objectToApplyTo, 422);
                 }
             }
             else
@@ -597,21 +589,18 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
                     if (array.Count <= positionAsInteger)
                     {
                         throw new JsonPatchException<T>(operation,
-                            string.Format("Patch failed: provided from path is invalid for array property type at " +
+                            Resources.FormatInvalidIndexForArrayProperty(operation.op, operation.from),
-                                "location from: {0}: invalid position",
+                            objectToApplyTo);
-                                operation.from),
-                            objectToApplyTo, 422);
                     }
 
                     valueAtFromLocation = array[positionAsInteger];
                 }
                 else
                 {
-                    throw new JsonPatchException<T>(operation,
+                    throw new JsonPatchException<T>(
-                       string.Format("Patch failed: provided from path is invalid for array property type at " +
+                        operation,
-                            "location from: {0}: expected array",
+                        Resources.FormatInvalidPathForArrayProperty(operation.op, operation.from),
-                            operation.from),
+                        objectToApplyTo);
-                       objectToApplyTo, 422);
                 }
             }
             else
@@ -635,15 +624,15 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
             {
                 throw new JsonPatchException<T>(
                     operation,
-                    string.Format("Patch failed: property at location {0} does not exist", propertyPath),
+                    Resources.FormatPropertyDoesNotExist(propertyPath),
-                    objectToApplyTo, 422);
+                    objectToApplyTo);
             }
             if (patchProperty.Property.Ignored)
             {
                 throw new JsonPatchException<T>(
                     operation,
-                    string.Format("Patch failed: cannot update property at location {0}", propertyPath),
+                    Resources.FormatCannotUpdateProperty(propertyPath),
-                    objectToApplyTo, 422);
+                    objectToApplyTo);
             }
         }
 
@@ -660,10 +649,12 @@ namespace Microsoft.AspNet.JsonPatch.Adapters
             Operation<T> operation,
             string path)
         {
-            var errorMessage = "Patch failed: provided value is invalid for property type at location path: ";
             if (!result.CanBeConverted)
             {
-                throw new JsonPatchException<T>(operation, string.Format(errorMessage + "{0}", path), objectToApplyTo, 422);
+                throw new JsonPatchException<T>(
+                    operation,
+                    Resources.FormatInvalidValueForProperty(result.ConvertedInstance, path),
+                    objectToApplyTo);
             }
         }
     }

src/Microsoft.AspNet.JsonPatch/Converters/TypedJsonPatchDocumentConverter.cs

@@ -60,7 +60,7 @@ namespace Microsoft.AspNet.JsonPatch.Converters
             }
             catch (Exception ex)
             {
-                throw new JsonPatchException("The JsonPatchDocument was malformed and could not be parsed.", ex, 400);
+                throw new JsonPatchException(Resources.FormatInvalidJsonPatchDocument(objectType.Name), ex);
             }
         }
 

src/Microsoft.AspNet.JsonPatch/Exceptions/JsonPatchException.cs

@@ -33,15 +33,8 @@ namespace Microsoft.AspNet.JsonPatch.Exceptions
             AffectedObject = affectedObject;
         }
 
-        public JsonPatchException(Operation<T> operation, string message, T affectedObject, int statusCode)
+        public JsonPatchException(Operation<T> operation, string message, T affectedObject, Exception innerException)
             : this(operation, message, affectedObject)
-        {
-            StatusCode = statusCode;
-        }
-
-        public JsonPatchException(Operation<T> operation, string message, T affectedObject,
-            int statusCode, Exception innerException)
-            : this(operation, message, affectedObject, statusCode)
         {
             InnerException = innerException;
         }

src/Microsoft.AspNet.JsonPatch/Exceptions/JsonPatchExceptionBase.cs

@@ -9,8 +9,6 @@ namespace Microsoft.AspNet.JsonPatch.Exceptions
     {
         public new Exception InnerException { get; internal set; }
 
-        public int StatusCode { get; internal set; }
-
         public object AffectedObject { get; private set; }
 
         private string _message = "";
@@ -33,13 +31,5 @@ namespace Microsoft.AspNet.JsonPatch.Exceptions
             _message = message;
             InnerException = innerException;
         }
-
-
-        public JsonPatchException(string message, Exception innerException, int statusCode)
-            : this(message, innerException)
-        {
-            StatusCode = statusCode;
-        }
-
     }
 }

src/Microsoft.AspNet.JsonPatch/Properties/Resources.Designer.cs

@@ -0,0 +1,126 @@
+// <auto-generated />
+namespace Microsoft.AspNet.JsonPatch
+{
+    using System.Globalization;
+    using System.Reflection;
+    using System.Resources;
+
+    internal static class Resources
+    {
+        private static readonly ResourceManager _resourceManager
+            = new ResourceManager("Microsoft.AspNet.JsonPatch.Resources", typeof(Resources).GetTypeInfo().Assembly);
+
+        /// <summary>
+        /// The property at path '{0}' could not be updated.
+        /// </summary>
+        internal static string CannotUpdateProperty
+        {
+            get { return GetString("CannotUpdateProperty"); }
+        }
+
+        /// <summary>
+        /// The property at path '{0}' could not be updated.
+        /// </summary>
+        internal static string FormatCannotUpdateProperty(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("CannotUpdateProperty"), p0);
+        }
+
+        /// <summary>
+        /// For operation '{0}' on array property at path '{1}', the index is larger than the array size.
+        /// </summary>
+        internal static string InvalidIndexForArrayProperty
+        {
+            get { return GetString("InvalidIndexForArrayProperty"); }
+        }
+
+        /// <summary>
+        /// For operation '{0}' on array property at path '{1}', the index is larger than the array size.
+        /// </summary>
+        internal static string FormatInvalidIndexForArrayProperty(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("InvalidIndexForArrayProperty"), p0, p1);
+        }
+
+        /// <summary>
+        /// The type '{0}' was malformed and could not be parsed.
+        /// </summary>
+        internal static string InvalidJsonPatchDocument
+        {
+            get { return GetString("InvalidJsonPatchDocument"); }
+        }
+
+        /// <summary>
+        /// The type '{0}' was malformed and could not be parsed.
+        /// </summary>
+        internal static string FormatInvalidJsonPatchDocument(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("InvalidJsonPatchDocument"), p0);
+        }
+
+        /// <summary>
+        /// For operation '{0}', the provided path is invalid for array property at path '{1}'.
+        /// </summary>
+        internal static string InvalidPathForArrayProperty
+        {
+            get { return GetString("InvalidPathForArrayProperty"); }
+        }
+
+        /// <summary>
+        /// For operation '{0}', the provided path is invalid for array property at path '{1}'.
+        /// </summary>
+        internal static string FormatInvalidPathForArrayProperty(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("InvalidPathForArrayProperty"), p0, p1);
+        }
+
+        /// <summary>
+        /// The value '{0}' is invalid for property at path '{1}'.
+        /// </summary>
+        internal static string InvalidValueForProperty
+        {
+            get { return GetString("InvalidValueForProperty"); }
+        }
+
+        /// <summary>
+        /// The value '{0}' is invalid for property at path '{1}'.
+        /// </summary>
+        internal static string FormatInvalidValueForProperty(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("InvalidValueForProperty"), p0, p1);
+        }
+
+        /// <summary>
+        /// Property does not exist at path '{0}'.
+        /// </summary>
+        internal static string PropertyDoesNotExist
+        {
+            get { return GetString("PropertyDoesNotExist"); }
+        }
+
+        /// <summary>
+        /// Property does not exist at path '{0}'.
+        /// </summary>
+        internal static string FormatPropertyDoesNotExist(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("PropertyDoesNotExist"), p0);
+        }
+
+        private static string GetString(string name, params string[] formatterNames)
+        {
+            var value = _resourceManager.GetString(name);
+
+            System.Diagnostics.Debug.Assert(value != null);
+
+            if (formatterNames != null)
+            {
+                for (var i = 0; i < formatterNames.Length; i++)
+                {
+                    value = value.Replace("{" + formatterNames[i] + "}", "{" + i + "}");
+                }
+            }
+
+            return value;
+        }
+    }
+}

src/Microsoft.AspNet.JsonPatch/Resources.resx

@@ -0,0 +1,138 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="CannotUpdateProperty" xml:space="preserve">
+    <value>The property at path '{0}' could not be updated.</value>
+  </data>
+  <data name="InvalidIndexForArrayProperty" xml:space="preserve">
+    <value>For operation '{0}' on array property at path '{1}', the index is larger than the array size.</value>
+  </data>
+  <data name="InvalidJsonPatchDocument" xml:space="preserve">
+    <value>The type '{0}' was malformed and could not be parsed.</value>
+  </data>
+  <data name="InvalidPathForArrayProperty" xml:space="preserve">
+    <value>For operation '{0}', the provided path is invalid for array property at path '{1}'.</value>
+  </data>
+  <data name="InvalidValueForProperty" xml:space="preserve">
+    <value>The value '{0}' is invalid for property at path '{1}'.</value>
+  </data>
+  <data name="PropertyDoesNotExist" xml:space="preserve">
+    <value>Property does not exist at path '{0}'.</value>
+  </data>
+</root>

test/Microsoft.AspNet.JsonPatch.Test/NestedObjectTests.cs

@@ -281,7 +281,10 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Add<int>(o => o.SimpleDTO.IntegerList, 4, 4);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("For operation 'add' on array property at path '/simpledto/integerlist/4', the index is " +
+                "larger than the array size.", exception.Message);
+
         }
 
         [Fact]
@@ -304,7 +307,12 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() =>
+                {
+                    deserialized.ApplyTo(doc);
+                });
+            Assert.Equal("For operation 'add' on array property at path '/simpledto/integerlist/4', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -324,7 +332,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Add<int>(o => o.SimpleDTO.IntegerList, 4, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -347,7 +356,11 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() =>
+                {
+                    deserialized.ApplyTo(doc);
+                });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -514,7 +527,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Remove<int>(o => o.SimpleDTO.IntegerList, 3);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("For operation 'remove' on array property at path '/simpledto/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -537,7 +552,12 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() =>
+                {
+                    deserialized.ApplyTo(doc);
+                });
+            Assert.Equal("For operation 'remove' on array property at path '/simpledto/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -557,7 +577,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Remove<int>(o => o.SimpleDTO.IntegerList, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -580,7 +601,11 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() =>
+                {
+                    deserialized.ApplyTo(doc);
+                });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -988,7 +1013,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Replace<int>(o => o.SimpleDTO.IntegerList, 5, 3);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("For operation 'replace' on array property at path '/simpledto/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -1011,7 +1038,12 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() =>
+                {
+                    deserialized.ApplyTo(doc);
+                });
+            Assert.Equal("For operation 'replace' on array property at path '/simpledto/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -1031,7 +1063,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Replace<int>(o => o.SimpleDTO.IntegerList, 5, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -1054,7 +1087,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTOWithNestedDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTOWithNestedDTO>>(() => { deserialized.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/simpledto/integerlist/-1'.", exception.Message);
         }
 
         [Fact]

test/Microsoft.AspNet.JsonPatch.Test/ObjectAdapterTests.cs

@@ -112,7 +112,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Add<int>(o => o.IntegerList, 4, 4);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("For operation 'add' on array property at path '/integerlist/4', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -132,7 +134,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            Assert.Equal("For operation 'add' on array property at path '/integerlist/4', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -235,7 +239,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Add<int>(o => o.IntegerList, 4, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -255,7 +260,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -401,7 +407,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Remove<int>(o => o.IntegerList, 3);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("For operation 'remove' on array property at path '/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -421,7 +429,9 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            Assert.Equal("For operation 'remove' on array property at path '/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -438,7 +448,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Remove<int>(o => o.IntegerList, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { patchDoc.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -458,7 +469,8 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() => { deserialized.ApplyTo(doc); });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -622,11 +634,13 @@ namespace Microsoft.AspNet.JsonPatch.Test
             string serialized = "{\"Operations\": [{ \"op\": \"replace\", \"path\": \"/title\", \"value\": \"New Title\"}]}";
 
             // Act & Assert
-            Assert.Throws<JsonPatchException>(() =>
+            var exception = Assert.Throws<JsonPatchException>(() =>
             {
                 var deserialized
                     = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
             });
+
+            Assert.Equal("The type 'JsonPatchDocument`1' was malformed and could not be parsed.", exception.Message);
         }
 
         [Fact]
@@ -953,10 +967,12 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Replace<int>(o => o.IntegerList, 5, 3);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
             {
                 patchDoc.ApplyTo(doc);
             });
+            Assert.Equal("For operation 'replace' on array property at path '/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -975,10 +991,12 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
             {
                 deserialized.ApplyTo(doc);
             });
+            Assert.Equal("For operation 'replace' on array property at path '/integerlist/3', the index is " +
+                "larger than the array size.", exception.Message);
         }
 
         [Fact]
@@ -995,10 +1013,11 @@ namespace Microsoft.AspNet.JsonPatch.Test
             patchDoc.Replace<int>(o => o.IntegerList, 5, -1);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
             {
                 patchDoc.ApplyTo(doc);
             });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]
@@ -1018,10 +1037,11 @@ namespace Microsoft.AspNet.JsonPatch.Test
             var deserialized = JsonConvert.DeserializeObject<JsonPatchDocument<SimpleDTO>>(serialized);
 
             // Act & Assert
-            Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
+            var exception = Assert.Throws<JsonPatchException<SimpleDTO>>(() =>
             {
                 deserialized.ApplyTo(doc);
             });
+            Assert.Equal("Property does not exist at path '/integerlist/-1'.", exception.Message);
         }
 
         [Fact]