add integration test forcing mechanism=debian

- test is failing

plugins/modules/locale_gen.py

@@ -117,7 +117,7 @@ def __init_module__(self):
                 apply_change=self.apply_change_debian,
             ),
             glibc=dict(
-                available=ETC_LOCALE_GEN,
+                available=SUPPORTED_LOCALES,
                 apply_change=self.apply_change_glibc,
             ),
         )
@@ -151,7 +151,7 @@ def assert_available(self):
         checking either :
         * if the locale is present in /etc/locales.gen
         * or if the locale is present in /usr/share/i18n/SUPPORTED"""
-        regexp = r'^#?\s*(?P<locale>\S+[\._\S]+) (?P<charset>\S+)\s*$'
+        regexp = r'^\s*#?\s*(?P<locale>\S+[\._\S]+) (?P<charset>\S+)\s*$'
         locales_available = self.MECHANISMS[self.vars.mechanism]["available"]
 
         re_compiled = re.compile(regexp)

tests/integration/targets/locale_gen/tasks/main.yml

@@ -12,7 +12,25 @@
   ansible.builtin.meta: end_play
   when: ansible_distribution not in ('Ubuntu', 'Debian')
 
-- include_tasks: basic.yml
+- name: Run tests auto-detecting mechanism
+  ansible.builtin.include_tasks: basic.yml
+  loop: "{{ locale_list_basic }}"
+  loop_control:
+    loop_var: locale_basic
+
+- name: Remove /etc/locale.gen
+  ansible.builtin.file:
+    path: /etc/locale.gen
+    state: absent
+
+- name: Ensure /var/lib/locales/supported.d exists
+  ansible.builtin.file:
+    path: /var/lib/locales/supported.d
+    state: directory
+    recurse: true
+
+- name: Force mechanism to be debian
+  ansible.builtin.include_tasks: basic.yml
   loop: "{{ locale_list_basic }}"
   loop_control:
     loop_var: locale_basic