tests: add option to indicate which language to install in the base

do_tests.py

@@ -158,6 +158,10 @@
         c.has_section('odoo_scripts') and
         c.has_option('odoo_scripts', 'image') and
         c.get('odoo_scripts', 'image')) or os.path.basename(project_path)
+    languages = (
+        c.has_section('odoo_scripts') and
+        c.has_option('odoo_scripts', 'load-language') and
+        c.get('odoo_scripts', 'load-language')) or None
     image = "%s/%s:latest" % (registry, project)
     logging.debug("Docker image: %s", image)
 
@@ -231,6 +235,9 @@
         if nmspc.docker:
             install_args = list(args)
             install_args.append('--install-default')
+            if languages:
+                install_args.append('--load-language')
+                install_args.append(languages)
             if install_log_level:
                 install_args.append('--log-level')
                 install_args.append(install_log_level)