fix user_name_suggester spec

spec/components/user_name_suggester_spec.rb

@@ -10,6 +10,9 @@ describe UserNameSuggester do
   end
 
   describe '.suggest' do
+    before do
+      User.stubs(:username_length).returns(3..15)
+    end
 
     it "doesn't raise an error on nil username" do
       UserNameSuggester.suggest(nil).should be_nil
@@ -67,4 +70,4 @@ describe UserNameSuggester do
     end
   end
 
-end
+end