Unformat error source parameters using the prescribed key_formatter (#230)

* Run key_formatter.unformat on field error responses so field names are assigned correctly

* Added test for key formatted attribute error messages

Author: bdunham

lib/json_api_client/resource.rb

@@ -398,7 +398,7 @@ def save
       if last_result_set.has_errors?
         last_result_set.errors.each do |error|
           if error.source_parameter
-            errors.add(error.source_parameter, error.title || error.detail)
+            errors.add(self.class.key_formatter.unformat(error.source_parameter), error.title || error.detail)
           else
             errors.add(:base, error.title || error.detail)
           end

test/unit/server_side_error_test.rb

@@ -32,4 +32,18 @@ def test_can_handle_validation_strings
     assert_equal ["Email address is invalid"], user.errors.full_messages
   end
 
+  def test_can_handle_key_formatted_attribute_validation_strings
+    with_altered_config(User, :json_key_format => :dasherized_key) do
+      stub_request(:post, "http://example.com/users")
+        .to_return(headers: {content_type: "application/vnd.api+json"}, body: {
+          errors: [{source: {pointer: "/data/attributes/email-address"}, title: "Email address is invalid"}]
+        }.to_json)
+      
+      user = User.create(name: 'Bob', email_address: 'invalid email')
+      assert !user.persisted?
+      assert user.errors.present?
+      assert_equal ["Email address is invalid"], user.errors[:email_address]
+    end
+  end
+
 end