RFC: Json Api Errors (WIP)

- ActiveModelSerializers::JsonPointer
- ActiveModel::Serializer::Adapter::JsonApi::Error
- ActiveModel::Serializer::Adapter::JsonApi::Error.attributes
- Fix rubocop config

test/action_controller/json_api/errors_test.rb

@@ -0,0 +1,41 @@
+require 'test_helper'
+
+module ActionController
+  module Serialization
+    class JsonApi
+      class ErrorsTest < ActionController::TestCase
+        def test_active_model_with_multiple_errors
+          get :render_resource_with_errors
+
+          expected_errors_object =
+            { 'errors'.freeze =>
+              [
+                { :source => { :pointer => '/data/attributes/name' }, :detail => 'cannot be nil' },
+                { :source => { :pointer => '/data/attributes/name' }, :detail => 'must be longer' },
+                { :source => { :pointer => '/data/attributes/id' }, :detail => 'must be a uuid' }
+              ]
+          }.to_json
+          assert_equal json_reponse_body.to_json, expected_errors_object
+        end
+
+        def json_reponse_body
+          JSON.load(@response.body)
+        end
+
+        class ErrorsTestController < ActionController::Base
+          def render_resource_with_errors
+            resource = Profile.new(name: 'Name 1',
+                                   description: 'Description 1',
+                                   comments: 'Comments 1')
+            resource.errors.add(:name, 'cannot be nil')
+            resource.errors.add(:name, 'must be longer')
+            resource.errors.add(:id, 'must be a uuid')
+            render json: resource, adapter: :json_api
+          end
+        end
+
+        tests ErrorsTestController
+      end
+    end
+  end
+end

test/active_model_serializers/adapter_for_test.rb

@@ -102,7 +102,8 @@ module ActiveModelSerializers
         'null'.freeze              => ActiveModelSerializers::Adapter::Null,
         'json'.freeze              => ActiveModelSerializers::Adapter::Json,
         'attributes'.freeze => ActiveModelSerializers::Adapter::Attributes,
-        'json_api'.freeze => ActiveModelSerializers::Adapter::JsonApi
+        'json_api'.freeze => ActiveModelSerializers::Adapter::JsonApi,
+        'json_api/error'.freeze => ActiveModelSerializers::Adapter::JsonApi::Error
       }
       actual = ActiveModelSerializers::Adapter.adapter_map
       assert_equal actual, expected_adapter_map
@@ -113,6 +114,7 @@ module ActiveModelSerializers
         'attributes'.freeze,
         'json'.freeze,
         'json_api'.freeze,
+        'json_api/error'.freeze,
         'null'.freeze
       ]
     end

test/active_model_serializers/json_pointer_test.rb

@@ -0,0 +1,20 @@
+require 'test_helper'
+
+class ActiveModelSerializers::JsonPointerTest < ActiveSupport::TestCase
+  def test_attribute_pointer
+    attribute_name = 'title'
+    pointer = ActiveModelSerializers::JsonPointer.new(:attribute, attribute_name)
+    assert_equal '/data/attributes/title', pointer
+  end
+
+  def test_primary_data_pointer
+    pointer = ActiveModelSerializers::JsonPointer.new(:primary_data)
+    assert_equal '/data', pointer
+  end
+
+  def test_unkown_data_pointer
+    assert_raises(TypeError) do
+      ActiveModelSerializers::JsonPointer.new(:unknown)
+    end
+  end
+end

test/adapter/json_api/errors_test.rb

@@ -0,0 +1,64 @@
+require 'test_helper'
+
+module ActiveModelSerializers
+  module Adapter
+    class JsonApi < Base
+      class ErrorsTest < Minitest::Test
+        include ActiveModel::Serializer::Lint::Tests
+
+        def setup
+          @resource = ModelWithErrors.new
+        end
+
+        def test_active_model_with_error
+          options = {
+              serializer: ActiveModel::Serializer::ErrorSerializer,
+              adapter: :'json_api/error'
+          }
+
+          @resource.errors.add(:name, 'cannot be nil')
+
+          serializable_resource = ActiveModel::SerializableResource.new(@resource, options)
+          assert_equal serializable_resource.serializer_instance.attributes, {}
+          assert_equal serializable_resource.serializer_instance.object, @resource
+
+          expected_errors_object =
+            { 'errors'.freeze =>
+              [
+                {
+                  source: { pointer: '/data/attributes/name' },
+                  detail: 'cannot be nil'
+                }
+              ]
+          }
+          assert_equal serializable_resource.as_json, expected_errors_object
+        end
+
+        def test_active_model_with_multiple_errors
+          options = {
+              serializer: ActiveModel::Serializer::ErrorSerializer,
+              adapter: :'json_api/error'
+          }
+
+          @resource.errors.add(:name, 'cannot be nil')
+          @resource.errors.add(:name, 'must be longer')
+          @resource.errors.add(:id, 'must be a uuid')
+
+          serializable_resource = ActiveModel::SerializableResource.new(@resource, options)
+          assert_equal serializable_resource.serializer_instance.attributes, {}
+          assert_equal serializable_resource.serializer_instance.object, @resource
+
+          expected_errors_object =
+            { 'errors'.freeze =>
+              [
+                { :source => { :pointer => '/data/attributes/name' }, :detail => 'cannot be nil' },
+                { :source => { :pointer => '/data/attributes/name' }, :detail => 'must be longer' },
+                { :source => { :pointer => '/data/attributes/id' }, :detail => 'must be a uuid' }
+              ]
+          }
+          assert_equal serializable_resource.as_json, expected_errors_object
+        end
+      end
+    end
+  end
+end

test/fixtures/poro.rb

@@ -27,6 +27,17 @@ class Model < ActiveModelSerializers::Model
   end
 end
 
+# see
+# https://github.com/rails/rails/blob/4-2-stable/activemodel/lib/active_model/errors.rb
+# The below allows you to do:
+#
+#   model = ModelWithErrors.new
+#   model.validate!            # => ["cannot be nil"]
+#   model.errors.full_messages # => ["name cannot be nil"]
+class ModelWithErrors < ::ActiveModelSerializers::Model
+  attr_accessor :name
+end
+
 class Profile < Model
 end
 

test/lint_test.rb

@@ -27,6 +27,15 @@ module ActiveModel
         def updated_at
         end
 
+        def errors
+        end
+
+        def self.human_attribute_name(attr, options = {})
+        end
+
+        def self.lookup_ancestors
+        end
+
         def self.model_name
           @_model_name ||= ActiveModel::Name.new(self)
         end

test/serializable_resource_test.rb

@@ -31,5 +31,37 @@ module ActiveModel
     def test_use_adapter_with_adapter_option_as_false
       refute ActiveModel::SerializableResource.new(@resource, { adapter: false }).use_adapter?
     end
+
+    class SerializableResourceErrorsTest < Minitest::Test
+      def test_serializable_resource_with_errors
+        options = nil
+        resource = ModelWithErrors.new
+        resource.errors.add(:name, 'must be awesome')
+        serializable_resource = ActiveModel::SerializableResource.new(resource)
+        expected_response_document =
+          { 'errors'.freeze =>
+            [
+              { :source => { :pointer => '/data/attributes/name' }, :detail => 'must be awesome' }
+            ]
+        }
+        assert_equal serializable_resource.as_json(options), expected_response_document
+      end
+
+      def test_serializable_resource_with_collection_containing_errors
+        options = nil
+        resources = []
+        resources << resource = ModelWithErrors.new
+        resource.errors.add(:title, 'must be amazing')
+        resources << ModelWithErrors.new
+        serializable_resource = ActiveModel::SerializableResource.new(resources)
+        expected_response_document =
+          { 'errors'.freeze =>
+            [
+              { :source => { :pointer => '/data/attributes/title' }, :detail => 'must be amazing' }
+            ]
+        }
+        assert_equal serializable_resource.as_json(options), expected_response_document
+      end
+    end
   end
 end