Try using the capybara rspec matcher have_select(locator, options = {}) instead:
#Find a select box by (label) name or id and assert the given text is selected
Then /^"([^"]*)" should be selected for "([^"]*)"$/ do |selected_text, dropdown|
expect(page).to have_select(dropdown, :selected => selected_text)
end
#Find a select box by (label) name or id and assert the expected option is present
Then /^"([^"]*)" should contain "([^"]*)"$/ do |dropdown, text|
expect(page).to have_select(dropdown, :options => [text])
end