diff --git a/tests/gantry_common_options_spec.sh b/tests/gantry_common_options_spec.sh
index a031cb9..3da56c2 100644
--- a/tests/gantry_common_options_spec.sh
+++ b/tests/gantry_common_options_spec.sh
@@ -62,6 +62,7 @@ Describe 'common-options'
       The stderr should satisfy spec_expect_no_message "${SKIP_REMOVING_IMAGES}"
       The stderr should satisfy spec_expect_no_message "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_no_message "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
       The stderr should satisfy spec_expect_no_message "${SLEEP_SECONDS_BEFORE_NEXT_UPDATE}"
     End
   End
@@ -129,6 +130,52 @@ Describe 'common-options'
       The stderr should satisfy spec_expect_message    "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_no_message "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_message    "Post update"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
+      The stderr should satisfy spec_expect_no_message "${SLEEP_SECONDS_BEFORE_NEXT_UPDATE}"
+    End
+  End
+  Describe "test_common_SLEEP_SECONDS" "container_test:false"
+    TEST_NAME="test_common_SLEEP_SECONDS"
+    IMAGE_WITH_TAG=$(get_image_with_tag "${SUITE_NAME}")
+    SERVICE_NAME="gantry-test-$(unique_id)"
+    test_common_SLEEP_SECONDS() {
+      local TEST_NAME="${1}"
+      local SERVICE_NAME="${2}"
+      reset_gantry_env "${SERVICE_NAME}"
+      export GANTRY_SLEEP_SECONDS="5"
+      timeout --preserve-status 15 bash -c "run_gantry ${TEST_NAME}"
+    }
+    BeforeEach "common_setup_no_new_image ${TEST_NAME} ${IMAGE_WITH_TAG} ${SERVICE_NAME}"
+    AfterEach "common_cleanup ${TEST_NAME} ${IMAGE_WITH_TAG} ${SERVICE_NAME}"
+    It 'run_test'
+      When run test_common_SLEEP_SECONDS "${TEST_NAME}" "${SERVICE_NAME}"
+      The status should be failure
+      The stdout should satisfy display_output
+      The stderr should satisfy display_output
+      The stderr should satisfy spec_expect_multiple_messages "${SKIP_UPDATING}.*${SERVICE_NAME}.*${SKIP_REASON_CURRENT_IS_LATEST}"
+      The stderr should satisfy spec_expect_no_message        "${PERFORM_UPDATING}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_SKIP_JOBS}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_INSPECT_FAILURE}"
+      The stderr should satisfy spec_expect_multiple_messages "${NUM_SERVICES_NO_NEW_IMAGES}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_UPDATING}"
+      The stderr should satisfy spec_expect_no_message        "${ADDING_OPTIONS}"
+      The stderr should satisfy spec_expect_no_message        "${UPDATED}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_no_message        "${NO_UPDATES}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_no_message        "${ROLLING_BACK}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_no_message        "${FAILED_TO_ROLLBACK}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_no_message        "${ROLLED_BACK}.*${SERVICE_NAME}"
+      The stderr should satisfy spec_expect_multiple_messages "${NO_SERVICES_UPDATED}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_UPDATED}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_UPDATE_FAILED}"
+      The stderr should satisfy spec_expect_no_message        "${NUM_SERVICES_ERRORS}"
+      The stderr should satisfy spec_expect_multiple_messages "${NO_IMAGES_TO_REMOVE}"
+      The stderr should satisfy spec_expect_no_message        "${REMOVING_NUM_IMAGES}"
+      The stderr should satisfy spec_expect_no_message        "${SKIP_REMOVING_IMAGES}"
+      The stderr should satisfy spec_expect_no_message        "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message        "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      # Check messages between iterations.
+      The stderr should satisfy spec_expect_message           "${SCHEDULE_NEXT_UPDATE_AT}"
+      The stderr should satisfy spec_expect_message           "${SLEEP_SECONDS_BEFORE_NEXT_UPDATE}"
     End
   End
   Describe "test_common_SLEEP_SECONDS_not_a_number" "container_test:false"
@@ -171,6 +218,7 @@ Describe 'common-options'
       The stderr should satisfy spec_expect_no_message "${SKIP_REMOVING_IMAGES}"
       The stderr should satisfy spec_expect_no_message "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_no_message "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
       The stderr should satisfy spec_expect_no_message "${SLEEP_SECONDS_BEFORE_NEXT_UPDATE}"
     End
   End
diff --git a/tests/gantry_service_single_spec.sh b/tests/gantry_service_single_spec.sh
index 53f0599..061963b 100644
--- a/tests/gantry_service_single_spec.sh
+++ b/tests/gantry_service_single_spec.sh
@@ -57,6 +57,7 @@ Describe 'service-single-service'
       The stderr should satisfy spec_expect_no_message "${SKIP_REMOVING_IMAGES}"
       The stderr should satisfy spec_expect_no_message "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_no_message "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
     End
   End
   Describe "test_new_image_yes" "container_test:true"
@@ -97,6 +98,7 @@ Describe 'service-single-service'
       The stderr should satisfy spec_expect_no_message "${SKIP_REMOVING_IMAGES}"
       The stderr should satisfy spec_expect_message    "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_no_message "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
     End
   End
   Describe "test_new_image_no_digest" "container_test:true"
@@ -148,6 +150,7 @@ Describe 'service-single-service'
       # Failed to removing the old image due to it has no digest.
       The stderr should satisfy spec_expect_no_message "${REMOVED_IMAGE}.*${IMAGE_WITH_TAG}"
       The stderr should satisfy spec_expect_message    "${FAILED_TO_REMOVE_IMAGE}.*${IMAGE_WITH_TAG}"
+      The stderr should satisfy spec_expect_no_message "${SCHEDULE_NEXT_UPDATE_AT}"
     End
   End
 End # Describe 'Simple'
diff --git a/tests/spec_gantry_test_helper.sh b/tests/spec_gantry_test_helper.sh
index 848716b..08f2cc3 100644
--- a/tests/spec_gantry_test_helper.sh
+++ b/tests/spec_gantry_test_helper.sh
@@ -15,6 +15,8 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #
 
+set -a
+
 # Constant strings for checks.
 export MUST_BE_A_NUMBER="must be a number"
 export SKIP_UPDATING_ALL="Skip updating all services"
@@ -51,6 +53,7 @@ export REMOVING_NUM_IMAGES="Removing [0-9]+ image\(s\)"
 export SKIP_REMOVING_IMAGES="Skip removing images"
 export REMOVED_IMAGE="Removed image"
 export FAILED_TO_REMOVE_IMAGE="Failed to remove image"
+export SCHEDULE_NEXT_UPDATE_AT="Schedule next update at"
 export SLEEP_SECONDS_BEFORE_NEXT_UPDATE="Sleep [0-9]+ seconds before next update"
 
 display_output() {
@@ -155,6 +158,10 @@ spec_expect_message() {
   _expect_message "${spec_expect_message:-""}" "${1}"
 }
 
+spec_expect_multiple_messages() {
+  _expect_multiple_messages "${spec_expect_multiple_messages:-""}" "${1}"
+}
+
 spec_expect_no_message() {
   _expect_no_message "${spec_expect_no_message:-""}" "${1}"
 }
@@ -387,6 +394,22 @@ _handle_failure() {
   echo -e "${RED}ERROR${NO_COLOR} ${MESSAGE}"
 }
 
+_expect_multiple_messages() {
+  TEXT="${1}"
+  MESSAGE="${2}"
+  local GREEN='\033[0;32m'
+  local NO_COLOR='\033[0m'
+  if ! ACTUAL_MSG=$(echo "${TEXT}" | grep -Po "${MESSAGE}"); then
+    _handle_failure "Failed to find expected message \"${MESSAGE}\"."
+    return 1
+  fi
+  if ! COUNT=$(echo "${TEXT}" | grep -Poc "${MESSAGE}"); then
+    _handle_failure "Failed to find multiple expected messages \"${MESSAGE}\" COUNT=${COUNT}."
+    return 1
+  fi
+  echo -e "${GREEN}EXPECTED${NO_COLOR} found ${COUNT} messages: ${ACTUAL_MSG}"
+}
+
 _expect_message() {
   TEXT="${1}"
   MESSAGE="${2}"
@@ -598,6 +621,11 @@ _get_script_dir() {
   # SC3054 (warning): In POSIX sh, array references are undefined.
   # shellcheck disable=SC3054
   SCRIPT_DIR="$( cd "$(dirname "${BASH_SOURCE[0]}")" || return 1; pwd -P )"
+  if [ -d "${SCRIPT_DIR}/.git" ]; then
+    # We may reach here if SCRIPT_DIR is "pwd -P".
+    # Assume .git is in the project root folder, but not in the tests folder.
+    SCRIPT_DIR="${SCRIPT_DIR}/tests"
+  fi
   echo "${SCRIPT_DIR}"
 }
 
@@ -707,3 +735,5 @@ run_gantry() {
   ENTRYPOINT=$(_get_entrypoint) || return 1
   ${ENTRYPOINT} "${STACK}"
 }
+
+set +a