Adds a ticker to the QuotedItem.

spec/unit/quoted_item_spec.rb

@@ -1,18 +1,58 @@
-class QuotedItem
-  def initialize
-
+class QuotedItem    
+  attr_reader :ticker
+
+  def initialize(ticker) 
+    validate_ticker(ticker)
+    @ticker = ticker
   end
-
+
+  private
+
+  def validate_ticker(ticker)
+    unless ticker.class == String
+      raise ArgumentError, "Ticker must be a valid string", caller
+    end
+    raise ArgumentError, "Ticker cannot be blank", caller if ticker == "" 
+  end  
 end         
 
 describe QuotedItem do
-  it "exists" do
-    subject.should be_true
-  end                     
-
-  describe ".new" do
-    it "creates an instance" do
-      QuotedItem.new.should be_instance_of QuotedItem
+  context "when created with valid attributes" do
+    subject do
+      QuotedItem.new("TEST.L")
+    end
+
+    it "creates an instance" do      
+      subject.should be_instance_of QuotedItem
+    end                    
+
+    it "has a ticker" do
+      subject.ticker.should == "TEST.L"
+    end                          
+  end
+
+  context "when created with invalid attributes" do
+    it "raises an ArgumentError when there are no attributes" do      
+      expect {QuotedItem.new()}.to raise_error ArgumentError
     end                    
+
+    describe "raises an ArgumentError with invalid ticker types" do
+      def invalid_ticker_helper(ticker_type, message)
+        expect {QuotedItem.new(ticker_type)}.to raise_error ArgumentError, 
+          message        
+      end
+
+      it "like nil" do      
+        invalid_ticker_helper(nil, "Ticker must be a valid string")
+      end                    
+
+      it "like an integer" do      
+        invalid_ticker_helper(10, "Ticker must be a valid string")
+      end                          
+
+      it "like a blank string" do      
+        invalid_ticker_helper("", "Ticker cannot be blank")
+      end                        
+    end    
   end
 end