Add method to Note to create notes about status changes.

spec/models/note_spec.rb

@@ -70,6 +70,25 @@ describe Note do
     end
   end
 
+  describe '#create_status_change_note' do
+    let(:project)  { Factory.create(:project) }
+    let(:thing)    { Factory.create(:issue, :project => project) }
+    let(:author)   { Factory(:user) }
+    let(:status)   { 'new_status' }
+
+    subject { Note.create_status_change_note(thing, author, status) }
+
+    it 'creates and saves a Note' do
+      should be_a Note
+      subject.id.should_not be_nil
+    end
+
+    its(:noteable) { should == thing }
+    its(:project)  { should == thing.project }
+    its(:author)   { should == author }
+    its(:note)     { should =~ /Status changed to #{status}/ }
+  end
+
   describe :authorization do
     before do
       @p1 = project