[tests] Skip test gracefully if i18n package is missing

Bug: T225632
Change-Id: I2f588752ae86a410203ff5b722a8e35b14523032
---
M tests/l10n_tests.py
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tests/l10n_tests.py b/tests/l10n_tests.py
index 52bb522..d063f3a 100644
--- a/tests/l10n_tests.py
+++ b/tests/l10n_tests.py
@@ -61,10 +61,6 @@
             return test_template
 
         # create test methods for package messages processed by unittest
-        if not i18n.messages_available():
-            raise unittest.SkipTest("i18n messages package '{}' not available."
-                                    .format(i18n._messages_package_name))
-
         site = pywikibot.Site(dct['code'], dct['family'])
         codes = site.family.languages_by_size
         del site
@@ -92,6 +88,14 @@
     family = 'wikipedia'
     code = 'en'
 
+    @classmethod
+    def setUpClass(cls):
+        """Skip test gracefully if i18n package is missing."""
+        super(TestValidTemplate, cls).setUpClass()
+        if not i18n.messages_available():
+            raise unittest.SkipTest("i18n messages package '{}' not available."
+                                    .format(i18n._messages_package_name))
+
 
 class TestSites(TestCase):
 

