diff --git a/.github/workflows/ruby_event_store-outbox_test.yml b/.github/workflows/ruby_event_store-outbox_test.yml
index 02d569776e..0086256831 100644
--- a/.github/workflows/ruby_event_store-outbox_test.yml
+++ b/.github/workflows/ruby_event_store-outbox_test.yml
@@ -96,16 +96,6 @@ jobs:
         ruby-version: "${{ env.RUBY_VERSION }}"
         bundler-cache: true
         working-directory: "${{ env.WORKING_DIRECTORY }}"
-    - run: |
-        nix-shell --run "locale" -E"
-          with import <nixpkgs> { };
-          mkShell {
-            inputsFrom = [
-              (import ../../support/nix/redis.nix)
-            ];
-          }
-        "
-      working-directory: "${{ env.WORKING_DIRECTORY }}"
     - run: |
         nix-shell --run "make test" -E"
           with import <nixpkgs> { };
diff --git a/support/nix/redis.nix b/support/nix/redis.nix
index 5c31dfc792..748485e9ce 100644
--- a/support/nix/redis.nix
+++ b/support/nix/redis.nix
@@ -1,11 +1,15 @@
 with import <nixpkgs> {};
 
 mkShell {
-  buildInputs = [ redis ];
+  buildInputs = [ redis glibcLocales ];
 
   shellHook = ''
     ${builtins.readFile ./pushtrap.sh}
 
+    LOCALE_ARCHIVE = "${glibcLocales}/lib/locale/locale-archive"
+    LANG = "en_US.UTF-8"
+    LC_ALL = "en_US.UTF-8"
+
     TMP=$(mktemp -d)
     SOCKET=$TMP/redis.sock
     PIDFILE=$TMP/redis.pid