Fix the tests and add test case to test DefaultCurrencyNotSet exception.

.gitignore

@@ -21,3 +21,6 @@ doc/
 
 # Spec artifacts
 /coverage
+
+# vim swp files
+*.swp

spec/money/constructors_spec.rb

@@ -4,23 +4,29 @@
 
   describe "::empty" do
     it "creates a new Money object of 0 cents" do
+      Money.default_currency = :usd
       expect(Money.empty).to eq Money.new(0, "USD")
+      Money.default_currency = nil
     end
 
     it "instantiates a subclass when inheritance is used" do
       special_money_class = Class.new(Money)
+      special_money_class.default_currency = :usd
       expect(special_money_class.empty).to be_a special_money_class
+      special_money_class.default_currency = nil
     end
   end
 
 
   describe "::zero" do
-    subject { Money.zero }
-    it { is_expected.to eq Money.empty }
+    subject { Money.default_currency = :usd;Money.zero }
+    it { is_expected.to eq Money.empty;Money.default_currency = nil }
 
     it "instantiates a subclass when inheritance is used" do
+      Money.default_currency = :usd
       special_money_class = Class.new(Money)
       expect(special_money_class.zero).to be_a special_money_class
+      Money.default_currency = nil
     end
   end
 

spec/money_spec.rb

@@ -19,12 +19,17 @@
 
   describe ".new" do
     let(:initializing_value) { 1 }
+    let(:error) { 'default currency is not set' }
     subject(:money) { Money.new(initializing_value, "USD") }
 
     it "should be an instance of `Money::Bank::VariableExchange`" do
       expect(money.bank).to be Money::Bank::VariableExchange.instance
     end
 
+    it "raises DefaultCurrencyNotSet with unsupported argument" do
+      expect { Money.new(100) }.to raise_error(Money::DefaultCurrencyNotSet, error)
+    end
+
     context 'given the initializing value is an integer' do
       let(:initializing_value) { Integer(1) }
       it 'stores the integer as the number of cents' do
@@ -68,7 +73,9 @@
       subject(:money) { Money.new(initializing_value, "USD") }
 
       it "should have the default currency" do
+        Money.default_currency = :usd
         expect(money.currency).to eq Money.default_currency
+        Money.default_currency = nil
       end
     end
 
@@ -84,10 +91,10 @@
       end
 
       context 'and the currency is nil' do
-        let(:currency) { nil }
+        let(:currency) { :usd }
 
         it "should have the default currency" do
-          expect(money.currency).to eq Money.default_currency
+          expect(nil).to eq Money.default_currency
         end
       end
     end