update tests

tests/dictionaries/88valid_enum_variable_optional/00-base.xml

@@ -0,0 +1,22 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<rougail>
+    <variables>
+        <family name="general">
+            <variable name="mode_conteneur_actif" type="string" description="No change">
+                <value>a</value>
+            </variable>
+            <variable name="var" type="string" description="New variable" multi="True">
+                <value>a</value>
+                <value>b</value>
+                <value>c</value>
+            </variable>
+        </family>
+    </variables>
+    <constraints>
+        <check name="valid_enum" target="mode_conteneur_actif">
+            <param type="variable" optional="True">var</param>
+        </check>
+    </constraints>
+</rougail>
+<!-- vim: ts=4 sw=4 expandtab
+-->