diff --git a/.devel/tinytest.R b/.devel/tinytest.R
index 67d1d77e..c6cf571d 100644
--- a/.devel/tinytest.R
+++ b/.devel/tinytest.R
@@ -9,6 +9,8 @@ library("tinytest")
 library("stringi")
 library("methods")
 
+str(stringi::stri_info())
+
 # options(encoding="UTF-8")  # e.g., on Windows
 cat(stri_info(short=TRUE), "\n")
 
diff --git a/.github/workflows/r-icu-system.yml b/.github/workflows/r-icu-system.yml
index 2e282f8a..f7a277b2 100644
--- a/.github/workflows/r-icu-system.yml
+++ b/.github/workflows/r-icu-system.yml
@@ -33,5 +33,5 @@ jobs:
     - name: Test stringi
       run: |
         Rscript -e 'source(".devel/tinytest.R")'
-        LC_ALL="C" Rscript -e 'source(".devel/tinytest.R")'
-        LC_ALL="pl_PL" Rscript -e 'source(".devel/tinytest.R")'
+        LC_ALL="C.UTF-8" Rscript -e 'source(".devel/tinytest.R")'
+        LC_ALL="pl_PL.UTF-8" Rscript -e 'source(".devel/tinytest.R")'