3 files changed, 24 insertions, 4 deletions
diff --git a/app/models/concerns/checksum_support.rb b/app/models/concerns/checksum_support.rb
index a76995b0f..92103798e 100644
--- a/app/models/concerns/checksum_support.rb
+++ b/app/models/concerns/checksum_support.rb
@@ -24,10 +24,29 @@ module ChecksumSupport
     self.attributes.values
   end
 
+  def checksum_replace_nil_or_empty_values values
+    # Replace empty array by nil & nil by VALUE_FOR_NIL_ATTRIBUTE
+    values
+      .map { |x| x.present? && x || VALUE_FOR_NIL_ATTRIBUTE }
+      .map do |item|
+        item =
+          if item.kind_of?(Array)
+            checksum_replace_nil_or_empty_values(item)
+          else
+            item
+          end
+      end
+  end
+
   def current_checksum_source
-    source = self.checksum_attributes.map{ |x| x unless x.try(:empty?) }
-    source = source.map{ |x| x || VALUE_FOR_NIL_ATTRIBUTE }
-    source.map(&:to_s).join(SEPARATOR)
+    source = checksum_replace_nil_or_empty_values(self.checksum_attributes)
+    source.map{ |item|
+      if item.kind_of?(Array)
+        item.map{ |x| x.kind_of?(Array) ? "(#{x.join(',')})" : x }.join(',')
+      else
+        item
+      end
+    }.join(SEPARATOR)
   end
 
   def set_current_checksum_source
diff --git a/app/models/concerns/min_max_values_validation.rb b/app/models/concerns/min_max_values_validation.rb
index 9b2e0d548..eff779d81 100644
--- a/app/models/concerns/min_max_values_validation.rb
+++ b/app/models/concerns/min_max_values_validation.rb
@@ -2,6 +2,7 @@ module MinMaxValuesValidation
   extend ActiveSupport::Concern
 
   included do
+    validates_presence_of :minimum, :maximum
     validate :min_max_values_validation
   end
 
diff --git a/app/models/concerns/timetable_support.rb b/app/models/concerns/timetable_support.rb
index 8c49723fe..5242abc33 100644
--- a/app/models/concerns/timetable_support.rb
+++ b/app/models/concerns/timetable_support.rb
@@ -101,7 +101,7 @@ module TimetableSupport
       period.period_start = Date.parse(item['period_start'])
       period.period_end   = Date.parse(item['period_end'])
 
-      period.save if period === ActiveRecord::Base && period.changed?
+      period.save if period.is_a?(ActiveRecord::Base) && period.changed?
 
       item['id'] = period.id
     end