diff --git a/json-schema_builder.gemspec b/json-schema_builder.gemspec
index 040ee6f..7df32fc 100644
--- a/json-schema_builder.gemspec
+++ b/json-schema_builder.gemspec
@@ -26,4 +26,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'appraisal'
   spec.add_dependency 'activesupport', '>= 4.0'
   spec.add_dependency 'json-schema', '>= 2.1'
+  spec.add_dependency 'ostruct'
 end
diff --git a/lib/json/schema_builder/rspec_helper/deep_open_struct.rb b/lib/json/schema_builder/rspec_helper/deep_open_struct.rb
index b6ceb31..166e4c4 100644
--- a/lib/json/schema_builder/rspec_helper/deep_open_struct.rb
+++ b/lib/json/schema_builder/rspec_helper/deep_open_struct.rb
@@ -3,12 +3,8 @@ module SchemaBuilder
     module RSpecHelper
       class DeepOpenStruct < OpenStruct
         def initialize(hash = { })
-          @table = { }
-          hash.each_pair do |key, value|
-            key = key.to_sym
-            @table[key] = _transform value
-            new_ostruct_member key
-          end
+          transformed = hash.transform_keys(&:to_sym).transform_values { |v| _transform(v) }
+          super(transformed)
         end
 
         def ==(other)
diff --git a/spec/unit/dsl_spec.rb b/spec/unit/dsl_spec.rb
index 2105f13..6226ef0 100644
--- a/spec/unit/dsl_spec.rb
+++ b/spec/unit/dsl_spec.rb
@@ -27,12 +27,12 @@ def initialize(*args); end
       end
 
       it 'should dispatch to entity' do
-        expect(instance).to receive(:entity).with(:something, 1, foo: :bar).and_call_original
+        expect(instance).to receive(:entity).with(:something, 1, { foo: :bar }).and_call_original
         instance.something 1, foo: :bar
       end
 
       it 'should allow unnamed entities' do
-        expect(instance).to receive(:entity).with(:something, nil, foo: :bar).and_call_original
+        expect(instance).to receive(:entity).with(:something, nil, { foo: :bar }).and_call_original
         instance.something foo: :bar
       end
     end
@@ -60,7 +60,7 @@ def initialize(*args); end
 
       it 'should set the parent' do
         expect(instance.class).to receive(:new)
-          .with('name', parent: kind_of(klass)).and_call_original
+          .with('name', { parent: kind_of(klass) }).and_call_original
 
         entity = instance.entity :something, 'name'
         expect(entity).to be_a klass
diff --git a/spec/unit/entity_spec.rb b/spec/unit/entity_spec.rb
index 8b5e45e..913a3a2 100644
--- a/spec/unit/entity_spec.rb
+++ b/spec/unit/entity_spec.rb
@@ -130,7 +130,7 @@ def example
 
       it "should #{ validator }" do
         expect(JSON::Validator).to receive(validator)
-          .with subject.as_json, { }, working: true, opts: true
+          .with subject.as_json, { }, { working: true, opts: true }
         subject.send validator, { }, opts: true
       end
     end
diff --git a/spec/unit/schema_spec.rb b/spec/unit/schema_spec.rb
index 1a9b8f3..4567d21 100644
--- a/spec/unit/schema_spec.rb
+++ b/spec/unit/schema_spec.rb
@@ -181,7 +181,7 @@ def example
     describe "##{ validator }" do
       it "should #{ validator }" do
         expect(JSON::Validator).to receive(validator)
-          .with schema.as_json, { }, opts: true
+          .with schema.as_json, { }, { opts: true }
         schema.send validator, { }, opts: true
       end
     end