move @rounding_method from VariableExchange to Base

lib/money/bank/base.rb

@@ -41,6 +41,13 @@ def self.instance
         @@singleton ||= self.new
       end
 
+      attr_reader :rounding_method
+
+      # Initializes a new Money::Bank::Base object. An optional block can be
+      # passed to dictate the rounding method that +exchange_with+ can use.
+      def initialize(&block)
+        @rounding_method = block
+      end
 
       # @deprecated +#exchange+ will be removed in v3.2.0, use +#exchange_with+
       #

lib/money/bank/variable_exchange.rb

@@ -25,7 +25,7 @@ class VariableExchange < Base
       def initialize(&block)
         @rates = {}
         @mutex = Mutex.new
-        @rounding_method = block
+        super
       end
 
 

spec/bank/base_spec.rb

@@ -1,11 +1,18 @@
 require "spec_helper"
 
 describe Money::Bank::Base do
-
   before :each do
     @bank = Money::Bank::Base.new
   end
 
+  describe '#new with &block' do
+    it 'should store @rounding_method' do
+      proc = Proc.new{|n| n.ceil}
+      bank = Money::Bank::Base.new(&proc)
+      bank.rounding_method.should == proc
+    end
+  end
+
   describe '#exchange' do
     it 'should raise NotImplementedError' do
       lambda { @bank.exchange(100, 'USD', 'EUR') }.should raise_exception(NotImplementedError)
@@ -53,5 +60,4 @@
       lambda{@bank.send(:same_currency?, 'AAA', 'BBB')}.should raise_exception(Money::Currency::UnknownCurrency)
     end
   end
-
 end