diff --git a/db/seeds/development.rb b/db/seeds/development.rb
index 4a3d77e5..6fc8e050 100644
--- a/db/seeds/development.rb
+++ b/db/seeds/development.rb
@@ -3,7 +3,7 @@ FactoryGirl.create(:consumer)
 FactoryGirl.create(:consumer, name: 'openSAP')
 
 # users
-%w(admin external_user teacher).each { |factory_name| FactoryGirl.create(factory_name) }
+[:admin, :external_user, :teacher].each { |factory_name| FactoryGirl.create(factory_name) }
 
 # execution environments
 ExecutionEnvironment.create_factories
diff --git a/spec/factories/file_type.rb b/spec/factories/file_type.rb
index 5832083e..d1ec9baf 100644
--- a/spec/factories/file_type.rb
+++ b/spec/factories/file_type.rb
@@ -181,7 +181,7 @@ FactoryGirl.define do
     singleton_file_type
   end
 
-  %w(binary executable renderable).each do |attribute|
+  [:binary, :executable, :renderable].each do |attribute|
     trait(attribute) { send(attribute, true) }
   end
 
diff --git a/spec/factories/shared_traits.rb b/spec/factories/shared_traits.rb
index 109f02b8..ea39e926 100644
--- a/spec/factories/shared_traits.rb
+++ b/spec/factories/shared_traits.rb
@@ -1,5 +1,5 @@
 FactoryGirl.define do
-  %w(admin external_user teacher).each do |factory_name|
+  [:admin, :external_user, :teacher].each do |factory_name|
     trait :"created_by_#{factory_name}" do
       association :user, factory: factory_name
     end
diff --git a/spec/models/submission_spec.rb b/spec/models/submission_spec.rb
index a5c15960..71ee0841 100644
--- a/spec/models/submission_spec.rb
+++ b/spec/models/submission_spec.rb
@@ -18,7 +18,7 @@ describe Submission do
     expect(described_class.create.errors[:user_type]).to be_present
   end
 
-  %w(download render run test).each do |action|
+  [:download, :render, :run, :test].each do |action|
     describe "##{action}_url" do
       let(:url) { @submission.send(:"#{action}_url") }