diff --git a/tools/confidence_test.sh b/tools/confidence_test.sh
index ea4dd00..a2f1656 100755
--- a/tools/confidence_test.sh
+++ b/tools/confidence_test.sh
@@ -191,27 +191,25 @@ gpg --import keyrings/live/pubring.gpg
 
 # Pick a GID to use:
 # This users's default group:
-DEFAULT_GID_NAME=$(id -gn)
+DEFAULT_GID_NUM=$(id -g)
 # Pick a group that is not the default group:
-TEST_GID_NUM=$(id -G | fmt -1 | tail -n +2 | grep -xv "$(id -u)" | head -n 1)
-TEST_GID_NAME=$(python -c 'import grp; print grp.getgrgid('"$TEST_GID_NUM"').gr_name')
-echo "DEFAULT_GID_NAME=$DEFAULT_GID_NAME"
+TEST_GID_NUM=$(id -G | fmt -1 |  grep -xv "$(id -u)" | grep -xv "$(id -g)" | head -1)
+echo "DEFAULT_GID_NUM=$DEFAULT_GID_NUM"
 echo "TEST_GID_NUM=$TEST_GID_NUM"
-echo "TEST_GID_NAME=$TEST_GID_NAME"
 
 PHASE 'Bob postdeploys... default.'
 blackbox_postdeploy
 assert_file_exists secret.txt
 assert_file_exists secret.txt.gpg
 assert_file_md5hash secret.txt "08a3fa763a05c018a38e9924363b97e7"
-assert_file_group secret.txt "$DEFAULT_GID_NAME"
+assert_file_group secret.txt "$DEFAULT_GID_NUM"
 
 PHASE 'Bob postdeploys... with a GID.'
 blackbox_postdeploy "$TEST_GID_NUM"
 assert_file_exists secret.txt
 assert_file_exists secret.txt.gpg
 assert_file_md5hash secret.txt "08a3fa763a05c018a38e9924363b97e7"
-assert_file_group secret.txt "$TEST_GID_NAME"
+assert_file_group secret.txt "$TEST_GID_NUM"
 
 PHASE 'Bob cleans up the secret.'
 rm secret.txt
diff --git a/tools/test_functions.sh b/tools/test_functions.sh
index 87ebdf8..a0177ec 100755
--- a/tools/test_functions.sh
+++ b/tools/test_functions.sh
@@ -63,10 +63,10 @@ function assert_file_group() {
 
   case $(uname -s) in
     Darwin|FreeBSD )
-      found=$(stat -f '%Sg' "$file")
+      found=$(stat -f '%Dg' "$file")
       ;;
     Linux )
-      found=$(stat -c '%G' "$file")
+      found=$(stat -c '%g' "$file")
       ;;
     CYGWIN* )
       echo "ASSERT_FILE_GROUP: Running on Cygwin. Not being tested."