diff --git a/group/description_test.go b/group/description_test.go
index 0812e72..4335713 100644
--- a/group/description_test.go
+++ b/group/description_test.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"os"
+	"path/filepath"
 	"reflect"
 	"testing"
 )
@@ -204,6 +205,14 @@ func TestWritableGroups(t *testing.T) {
 		t.Errorf("GetDescription: got %v", err)
 	}
 
+	fi, err := os.Stat(filepath.Join(Directory, "test.json"))
+	if err != nil {
+		t.Errorf("Stat: %v", err)
+	}
+	if mode := fi.Mode(); mode != 0o600 {
+		t.Errorf("Mode is 0o%03o (expected 0o600)\n", mode)
+	}
+
 	desc, token, err := GetSanitisedDescription("test")
 	if err != nil || token == "" {
 		t.Errorf("GetSanitisedDescription: got %v", err)