Allow nil to be used as a default_currency

lib/money/currency.rb

@@ -33,6 +33,9 @@ def initialize(method, currency, attribute)
  # Thrown when an unknown currency is requested.
  class UnknownCurrency < ArgumentError; end
 
+ # Thrown when currency is not provided.
+ class NoCurrency < ArgumentError; end
+
  class << self
  def new(id)
  id = id.to_s.downcase

lib/money/money.rb

@@ -156,7 +156,9 @@ def self.default_currency
  @using_deprecated_default_currency = false
  end
 
- if @default_currency.respond_to?(:call)
+ if @default_currency.nil?
+ nil
+ elsif @default_currency.respond_to?(:call)
  Money::Currency.new(@default_currency.call)
  else
  Money::Currency.new(@default_currency)
@@ -338,7 +340,7 @@ class << self
  # Money.new(100, "USD") #=> #<Money @fractional=100 @currency="USD">
  # Money.new(100, "EUR") #=> #<Money @fractional=100 @currency="EUR">
  #
- def initialize( obj, currency = Money.default_currency, options = {})
+ def initialize(obj, currency = Money.default_currency, options = {})
  # For backwards compatability, if options is not a Hash, treat it as a bank parameter
  unless options.is_a?(Hash)
  options = { bank: options }
@@ -352,6 +354,7 @@ def initialize( obj, currency = Money.default_currency, options = {})
 
  # BigDecimal can be Infinity and NaN, money of that amount does not make sense
  raise ArgumentError, 'must be initialized with a finite value' unless @fractional.finite?
+ raise Currency::NoCurrency, 'must be provide a currency' if @currency.nil?
  end
 
  # Assuming using a currency using dollars:

spec/money_spec.rb

@@ -70,6 +70,21 @@
  it "should have the default currency" do
  expect(money.currency).to eq Money.default_currency
  end
+
+ context 'without a default' do
+ around do |example|
+ default_currency = Money.default_currency
+ Money.default_currency = nil
+
+ example.run
+
+ Money.default_currency = default_currency
+ end
+
+ it 'should throw an NoCurrency Error' do
+ expect { money }.to raise_error(Money::Currency::NoCurrency)
+ end
+ end
  end
 
  context 'given a currency is provided' do