Maybe/test/lib/money/currency_test.rb

require "test_helper"

class Money::CurrencyTest < ActiveSupport::TestCase
    setup do
        @currency = Money::Currency.new(:usd)
    end

    test "has many currencies" do
        assert_operator Money::Currency.all.count, :>, 100
    end

    test "can test equality of currencies" do
        assert_equal Money::Currency.new(:usd), Money::Currency.new(:usd)
        assert_not_equal Money::Currency.new(:usd), Money::Currency.new(:eur)
    end

    test "can get metadata about a currency" do
        assert_equal "USD", @currency.iso_code
        assert_equal "United States Dollar", @currency.name
        assert_equal "$", @currency.symbol
        assert_equal 1, @currency.priority
        assert_equal "Cent", @currency.minor_unit
        assert_equal 100, @currency.minor_unit_conversion
        assert_equal 1, @currency.smallest_denomination
        assert_equal ".", @currency.separator
        assert_equal ",", @currency.delimiter
        assert_equal "%u%n", @currency.default_format
        assert_equal 2, @currency.default_precision
    end

    test "can extract cents string from amount" do
        value1 = Money.new(100)
        value2 = Money.new(100.1)
        value3 = Money.new(100.12)
        value4 = Money.new(100.123)
        value5 = Money.new(200, :jpy)

        assert_equal "00", value1.cents_str
        assert_equal "10", value2.cents_str
        assert_equal "12", value3.cents_str
        assert_equal "12", value4.cents_str
        assert_equal "", value5.cents_str

        assert_equal "", value4.cents_str(0)
        assert_equal "1", value4.cents_str(1)
        assert_equal "12", value4.cents_str(2)
        assert_equal "123", value4.cents_str(3)
    end
end