value.scan(/%\{(\w+)\}/) do
assert_includes variables, Regexp.last_match(1), "#{key} uses unknown interpolation variable #{Regexp.last_match(1)}"
value.scan(/%\{(\w+)\}/) do
assert_includes variables, Regexp.last_match(1), "#{key} uses unknown interpolation variable #{Regexp.last_match(1)}"