display small selects as radio buttons

app/models/champs/drop_down_list_champ.rb

@@ -1,2 +1,3 @@
 class Champs::DropDownListChamp < Champ
+  THRESHOLD_NB_OPTIONS_AS_RADIO = 3
 end

app/models/drop_down_list.rb

@@ -8,6 +8,10 @@ class DropDownList < ApplicationRecord
     result.blank? ? [] : [''] + result
   end
 
+  def enabled_non_empty_options
+    (options - disabled_options).reject(&:empty?)
+  end
+
   def disabled_options
     options.filter { |v| (v =~ /^--.*--$/).present? }
   end

app/views/shared/dossiers/editable_champs/_drop_down_list.html.haml

@@ -1,5 +1,15 @@
 - if champ.drop_down_list && champ.drop_down_list.options.any?
-  = form.select :value,
-    champ.drop_down_list.options,
-    disabled: champ.drop_down_list.disabled_options,
-    required: champ.mandatory?
+  - enabled_non_empty_options = champ.drop_down_list.enabled_non_empty_options
+  - if enabled_non_empty_options.size > Champs::DropDownListChamp::THRESHOLD_NB_OPTIONS_AS_RADIO
+    = form.select :value,
+      champ.drop_down_list.options,
+      disabled: champ.drop_down_list.disabled_options,
+      required: champ.mandatory?
+  - else
+    %fieldset.radios
+      %legend.mandatory-explanation
+        Sélectionnez une des valeurs
+      - enabled_non_empty_options.each do |option|
+        %label
+          = form.radio_button :value, option
+          = option