Validate roadmap_epics_state

app/models/user_preference.rb

@@ -51,3 +51,5 @@ class UserPreference < ActiveRecord::Base
     "#{field_key}_notes_filter"
   end
 end
+
+UserPreference.prepend(EE::UserPreference)

ee/app/controllers/groups/roadmap_controller.rb

@@ -38,10 +38,11 @@ module Groups
       return unless current_user
 
       preference = current_user.user_preference
-      state_id = Epic.states[params[:state]]
 
-      if params[:state].present? && state_id != preference.roadmap_epics_state
-        preference.update(roadmap_epics_state: state_id)
+      if params[:state].present?
+        preference.roadmap_epics_state = Epic.states[params[:state]]
+
+        preference.save if preference.changed? && Gitlab::Database.read_write?
       end
 
       Epic.states.key(preference.roadmap_epics_state)

ee/app/models/ee/user_preference.rb

+module EE
+  module UserPreference
+    extend ActiveSupport::Concern
+
+    prepended do
+      validates :roadmap_epics_state, allow_nil: true, inclusion: {
+        in: ::Epic.states.values, message: "%{value} is not a valid epic state"
+      }
+    end
+  end
+end

ee/spec/models/user_preference_spec.rb

+require 'spec_helper'
+
+describe UserPreference do
+  let(:user_preference) { create(:user_preference) }
+
+  shared_examples 'updates roadmap_epics_state' do |state|
+    it 'saves roadmap_epics_state in user_preference' do
+      user_preference.update(roadmap_epics_state: state)
+
+      expect(user_preference.reload.roadmap_epics_state).to eq(state)
+    end
+  end
+
+  describe 'roadmap_epics_state' do
+    context 'when set to open epics' do
+      it_behaves_like 'updates roadmap_epics_state', Epic.states[:opened]
+    end
+
+    context 'when set to closed epics' do
+      it_behaves_like 'updates roadmap_epics_state', Epic.states[:closed]
+    end
+
+    context 'when reset to all epics' do
+      it_behaves_like 'updates roadmap_epics_state', nil
+    end
+  end
+end