[mod] add test.pybabel to cover issues in translation tasks

We need to cover issue related to pybabel/translation tasks.  By example there
was an issue [1] (fixed [2]) when upgrading jinja2 from 3.0.3 to 3.1.0 [3] that
has not been covered by the CI tests.

[1] https://github.com/searxng/searxng/runs/5688624325?check_suite_focus=true#step:6:348
[2] https://github.com/searxng/searxng/pull/1011
[3] https://github.com/searxng/searxng/pull/1008

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

manage

@@ -745,6 +745,13 @@ test.rst() {
     done
 }
 
+test.pybabel() {
+    TEST_BABEL_FOLDER="build/test/pybabel"
+    build_msg TEST "[extract messages] pybabel"
+    mkdir -p "${TEST_BABEL_FOLDER}"
+    pyenv.cmd pybabel extract -F babel.cfg -o "${TEST_BABEL_FOLDER}/messages.pot" searx
+}
+
 test.clean() {
     build_msg CLEAN  "test stuff"
     rm -rf geckodriver.log .coverage coverage/