refactor(groupe instructeur): add valid_rule? method

Co-authored-by: LeSim <mail@simon.lehericey.net>

app/models/groupe_instructeur.rb

@@ -73,9 +73,12 @@ class GroupeInstructeur < ApplicationRecord
   end
 
   def invalid_rule?
-    rule = routing_rule
-    return true if !((rule.is_a?(Logic::Eq) || rule.is_a?(Logic::NotEq)) && rule.left.is_a?(Logic::ChampValue) && rule.right.is_a?(Logic::Constant))
-    return true if !routing_rule_matches_tdc?
+    !valid_rule?
+  end
+
+  def valid_rule?
+    return false if routing_rule.nil?
+    ([routing_rule.left, routing_rule, routing_rule.right] in [ChampValue, Eq | NotEq, Constant]) && routing_rule_matches_tdc?
   end
 
   def non_unique_rule?

spec/models/routing_engine_spec.rb

@@ -28,7 +28,7 @@ describe RoutingEngine, type: :model do
       context 'without any matching rules' do
         before do
           procedure.groupe_instructeurs.each do |gi|
-            gi.update(routing_rule: constant(false))
+            gi.update(routing_rule: ds_eq(constant(false), constant(false)))
           end
         end