diff --git a/.github/workflows/e2e-cache.yml b/.github/workflows/e2e-cache.yml
index 1601de11..07a1c644 100644
--- a/.github/workflows/e2e-cache.yml
+++ b/.github/workflows/e2e-cache.yml
@@ -144,7 +144,7 @@ jobs:
         if: matrix.os == 'windows-latest'
         run: bash "$GITHUB_WORKSPACE/__tests__/check-dir.sh" "$HOME/AppData/Local/Coursier/Cache"
       - name: Check files to cache on ubuntu-latest
-        if: matrix.os == 'ubuntu-latest'
+        if: matrix.os == 'ubuntu-22.04'
         run: bash "$GITHUB_WORKSPACE/__tests__/check-dir.sh" "$HOME/.cache/coursier"
   sbt-restore:
     runs-on: ${{ matrix.os }}
@@ -177,7 +177,7 @@ jobs:
         if: matrix.os == 'windows-latest'
         run: bash "$GITHUB_WORKSPACE/__tests__/check-dir.sh" "$HOME/AppData/Local/Coursier/Cache"
       - name: Confirm that ~/.cache/coursier directory has been made
-        if: matrix.os == 'ubuntu-latest'
+        if: matrix.os == 'ubuntu-22.04'
         run: bash "$GITHUB_WORKSPACE/__tests__/check-dir.sh" "$HOME/.cache/coursier"
   gradle1-save:
     runs-on: ${{ matrix.os }}
diff --git a/__tests__/check-dir.sh b/__tests__/check-dir.sh
index 9e2f3276..30da05fd 100755
--- a/__tests__/check-dir.sh
+++ b/__tests__/check-dir.sh
@@ -10,6 +10,11 @@
 # tilde-expansion pitfalls.
 set -eu
 
+if [ "$#" -lt 1 ]; then
+  echo "Usage: check-dir.sh <dir> [present|absent]" >&2
+  exit 2
+fi
+
 dir=$1
 mode=${2:-present}