diff --git a/cashtab/scripts/test.js b/cashtab/scripts/test.js
--- a/cashtab/scripts/test.js
+++ b/cashtab/scripts/test.js
@@ -5,6 +5,7 @@
 process.env.NODE_ENV = 'test';
 process.env.PUBLIC_URL = '';
 process.env.TZ = 'UTC';
+process.env.LANG = 'en_US.UTF-8';
 
 // Makes the script crash on unhandled rejections instead of silently
 // ignoring them. In the future, promise rejections that are not handled will