test for namespaced associations + bug fixed

lib/active_model/serializer.rb

@@ -116,7 +116,7 @@ end
       def build_serializer_class(resource, options)
         "".tap do |klass_name|
           klass_name << "#{options[:namespace]}::" if options[:namespace]
-          klass_name << prefix.to_s.classify       if options[:prefix]
+          klass_name << options[:prefix].to_s.classify       if options[:prefix]
           klass_name << "#{resource.class.name}Serializer"
         end
       end

lib/active_model/serializer/associations.rb

@@ -38,8 +38,8 @@ module ActiveModel
         @embed_objects = embed == :object || embed == :objects
       end
 
-      def serializer_from_object(object)
+      def serializer_from_object(object, options = {})
-        Serializer.serializer_for(object)
+        Serializer.serializer_for(object, options)
       end
 
       def default_serializer
@@ -47,7 +47,7 @@ module ActiveModel
       end
 
       def build_serializer(object, options = {})
-        serializer_class(object).new(object, options.merge(self.options))
+        serializer_class(object, options).new(object, options.merge(self.options))
       end
 
       class HasOne < Association
@@ -57,8 +57,8 @@ module ActiveModel
           @key ||= "#{name}_id"
         end
 
-        def serializer_class(object)
+        def serializer_class(object, options = {})
-          serializer_from_options || serializer_from_object(object) || default_serializer
+          serializer_from_options || serializer_from_object(object, options) || default_serializer
         end
 
         def build_serializer(object, options = {})
@@ -74,7 +74,7 @@ module ActiveModel
           @key ||= "#{name.to_s.singularize}_ids"
         end
 
-        def serializer_class(object)
+        def serializer_class(object, _ = {})
           if use_array_serializer?
             ArraySerializer
           else

test/fixtures/poro.rb

@@ -74,9 +74,7 @@ class WebLogLowerCamelSerializer < WebLogSerializer
   format_keys :lower_camel
 end
 
-class ShortUserSerializer < ActiveModel::Serializer
+class ShortProfileSerializer < ::ProfileSerializer; end
-  attributes :name
-end
 
 module TestNamespace
   class ProfileSerializer < ::ProfileSerializer; end

test/unit/active_model/serializer/associations/build_serializer_test.rb

@@ -7,6 +7,7 @@ module ActiveModel
         def setup
           @association = Association::HasOne.new('post', serializer: PostSerializer)
           @post = Post.new({ title: 'Title 1', body: 'Body 1', date: '1/1/2000' })
+          @user = User.new
         end
 
         def test_build_serializer_for_array_called_twice
@@ -15,6 +16,20 @@ module ActiveModel
             assert_instance_of(PostSerializer, serializer)
           end
         end
+
+        def test_build_serializer_from_in_a_namespace
+          assoc      = Association::HasOne.new('profile')
+          serializer = TestNamespace::UserSerializer.new(@user).build_serializer(assoc)
+
+          assert_instance_of(TestNamespace::ProfileSerializer, serializer)
+        end
+
+        def test_build_serializer_with_prefix
+          assoc      = Association::HasOne.new('profile', prefix: :short)
+          serializer = UserSerializer.new(@user).build_serializer(assoc)
+
+          assert_instance_of(ShortProfileSerializer, serializer)
+        end
       end
     end
   end