FIX: Don't suggest invalid username

lib/user_name_suggester.rb

@@ -42,14 +42,21 @@ module UserNameSuggester
     # 2. removes unallowed leading characters
     name.gsub!(/^\W+/, "")
     # 3. removes unallowed trailing characters
-    name.gsub!(/[^A-Za-z0-9]+$/, "")
+    name = remove_unallowed_trailing_characters(name)
     # 4. unify special characters
     name.gsub!(/[-_.]{2,}/, "_")
     name
   end
 
+  def self.remove_unallowed_trailing_characters(name)
+    name.gsub!(/[^A-Za-z0-9]+$/, "")
+    name
+  end
+
   def self.rightsize_username(name)
-    name.ljust(User.username_length.begin, '1')[0, User.username_length.end]
+    name = name[0, User.username_length.end]
+    name = remove_unallowed_trailing_characters(name)
+    name.ljust(User.username_length.begin, '1')
   end
 
 end

spec/components/user_name_suggester_spec.rb

@@ -93,6 +93,15 @@ describe UserNameSuggester do
     it 'should handle typical facebook usernames' do
       expect(UserNameSuggester.suggest('roger.nelson.3344913')).to eq('roger.nelson.33')
     end
+
+    it 'removes underscore at the end of long usernames that get truncated' do
+      expect(UserNameSuggester.suggest('uuuuuuuuuuuuuu_u')).to_not end_with('_')
+    end
+
+    it "adds number if it's too short after removing trailing underscore" do
+      User.stubs(:username_length).returns(8..8)
+      expect(UserNameSuggester.suggest('uuuuuuu_u')).to eq('uuuuuuu1')
+    end
   end
 
 end