Do it in in your spec_helper:
config.before :each, type: :controller do
request.env['HTTP_ACCEPT_LANGUAGE'] = "en"
end
Try this for both controller and feature specs:
config.before(:each) do |example|
if [:controller, :feature].include?(example.metadata[:type])
request.env['HTTP_ACCEPT_LANGUAGE'] = "en" # ugly
end
end