diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 217ebf7..627f35e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -39,6 +39,18 @@ jobs:
       - uses: astral-sh/setup-uv@v3
       - run: ./script/test.sh go
 
+  test-go-legacy-cog:
+    name: Test Go with legacy Cog
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - uses: astral-sh/setup-uv@v3
+      - run: ./script/test.sh go -legacy-cog
+
   build-python:
     name: Build & verify python package
     runs-on: ubuntu-latest
diff --git a/script/test.sh b/script/test.sh
index d661109..9ffa9a0 100755
--- a/script/test.sh
+++ b/script/test.sh
@@ -9,31 +9,31 @@ base_dir="$(git rev-parse --show-toplevel)"
 cd "$base_dir"
 
 test_go() {
-    go test ./...
+    go test ./... "$@"
 }
 
 test_python() {
     cd "$base_dir/python"
     uv sync --all-extras
-    .venv/bin/pytest
+    .venv/bin/pytest "$@"
 }
 
 if [ $# -eq 0 ]; then
     test_go
     test_python
 else
-    for c in "$@"; do
-        case "$c" in
-            go)
-                test_go
-                ;;
-            python)
-                test_python
-                ;;
-            *)
-                echo "Unknown test $c"
-                exit 1
-                ;;
-        esac
-    done
+    t=$1
+    shift
+    case "$t" in
+        go)
+            test_go "$@"
+            ;;
+        python)
+            test_python "$@"
+            ;;
+        *)
+            echo "Unknown test $t"
+            exit 1
+            ;;
+    esac
 fi