1..7
# ->configure()
ok 1 - ->configure() throws an InvalidArgumentException if a currency does not exist
ok 2 - ->configure() can restrict the number of currencies with the currencies option
# ->render()
ok 3 - ->render() renders all currencies as option tags
ok 4 - ->render() renders all currencies as option tags
ok 5 - ->render() does not output ICU dummy data
# add_empty
ok 6 - ->render() renders an empty option if add_empty is true
ok 7 - ->render() renders an empty option if add_empty is true
# Looks like everything went fine.