Resolve model specs with coercion fix

app/models/conference.rb

@@ -893,11 +893,12 @@ def get_events_per_week_by_state
 
     # Completed weeks
     events_per_week.each do |week, values|
+      week = week.respond_to?(:strftime) ? week : Date.parse(week)
       values.each do |state, value|
         next unless %i[confirmed unconfirmed].include?(state)
 
         result[state.to_s.capitalize] = {} unless result[state.to_s.capitalize]
-        result[state.to_s.capitalize][DateTime.parse(week).strftime('%W').to_i] = value
+        result[state.to_s.capitalize][week.strftime('%W').to_i] = value
       end
     end