User#add_user_token

app/models/user.rb

@@ -16,4 +16,7 @@ class User < ActiveRecord::Base
     end
   end
 
+  def add_user_token(token)
+    user_tokens.find_or_create_by_token(token)
+  end
 end

spec/models/user_spec.rb

@@ -47,4 +47,28 @@ describe User do
 
     end
   end
+
+  describe '#add_user_token' do
+    before { user.save }
+
+    context "when user doesn't have given token" do
+      let(:token) { Factory.attributes_for(:user_token)[:token] }
+
+      it 'returns created UserToken' do
+        ut = user.add_user_token(token)
+        ut.should be_kind_of(UserToken)
+        ut.id.should_not be(nil)
+      end
+    end
+
+    context "when user doesn't have given token" do
+      let(:existing_token) { Factory(:user_token, :user => user) }
+      let(:token) { existing_token.token }
+
+      it 'returns existing UserToken' do
+        ut = user.add_user_token(token)
+        ut.should == existing_token
+      end
+    end
+  end
 end