Add explicit locale during tests

This hopefully fixes an issue in travis where the locale would sometimes
change to German during the different tests.

wger/core/tests/base_testcase.py

@@ -23,6 +23,7 @@
 from django.conf import settings
 from django.core.cache import cache
 from django.test import TestCase
+from django.utils.translation import activate
 from django.urls import (
     NoReverseMatch,
     reverse
@@ -129,6 +130,9 @@ def setUp(self):
         # Don't check reCaptcha's entries
         os.environ['RECAPTCHA_TESTING'] = 'True'
 
+        # Explicitly set the locale to en, otherwise the CI might make problems
+        activate('en')
+
         # Test the mobile templates
         if os.environ.get('TEST_MOBILE') == 'True':
             settings.FLAVOURS = ('mobile',)