diff --git a/README.md b/README.md
index 63a8e06..3cf953d 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,7 @@ like to upgrade to, then change your docker image to match:
 
 ### "One shot" mode
 
-If you just want to perform the upgrade without starting PostgreSQL
+If you just want to perform the upgrade without running PostgreSQL
 afterwards, then you can use "[One Shot](https://github.com/pgautoupgrade/docker-pgautoupgrade/issues/13)" mode.
 
 To do that, add an environment variable called `PGAUTO_ONESHOT`
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 8549adc..a032f9a 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -575,9 +575,11 @@ _main() {
 
 			UPGRADE_PERFORMED=1
 
-			echo "**********************************************************"
-			echo "Automatic upgrade process finished with no errors reported"
-			echo "**********************************************************"
+			echo "***************************************************************************************"
+			echo "Automatic upgrade process finished upgrading the data format to PostgreSQL ${PGTARGET}."
+			echo "The database has not yet been reindexed nor updated the query planner stats.  Those    "
+			echo "will be done by a background task shortly.                                             "
+			echo "***************************************************************************************"
 		fi
 
 		### The main pgautoupgrade scripting ends here ###
@@ -614,6 +616,9 @@ _main() {
 			fi
 		fi
 	fi
+
+	# Run a sync before exiting, just to ensure everything is flushed to disk before docker terminates the process
+	sync
 }
 
 if ! _is_sourced; then
diff --git a/pgautoupgrade-postupgrade.sh b/pgautoupgrade-postupgrade.sh
index 4e628d3..3c6afa6 100755
--- a/pgautoupgrade-postupgrade.sh
+++ b/pgautoupgrade-postupgrade.sh
@@ -84,4 +84,7 @@ else
 	echo "*************************************************************************************************"
 	echo "Post upgrade tasks have finished successfully.  PostgreSQL should now be fully updated and online"
 	echo "*************************************************************************************************"
-fi
\ No newline at end of file
+fi
+
+# Run a sync before exiting, just to ensure everything is flushed to disk before docker terminates the process
+sync
\ No newline at end of file
diff --git a/test.sh b/test.sh
index 2b22615..4ed757f 100755
--- a/test.sh
+++ b/test.sh
@@ -6,6 +6,20 @@ FAILURE=0
 # Array of PostgreSQL versions for testing
 PG_VERSIONS=(9.5 9.6 10 11 12 13 14 15 16 17)
 
+# Useful output display
+banner() {
+    set +x
+    CHAR=$1
+    MSG=$2
+    NUMSTARS=$((${#MSG}+1))
+    echo
+    for i in $(seq 2 "$NUMSTARS"); do printf "%s" "${CHAR}"; done; echo
+    echo "${MSG}"
+    for i in $(seq 2 "$NUMSTARS"); do printf "%s" "${CHAR}"; done; echo
+    echo
+    set -x
+}
+
 # Stop any existing containers from previous test runs
 test_down() {
     docker compose -f test/docker-compose-pgauto.yml down
@@ -31,21 +45,42 @@ test_run() {
     # Verify the PostgreSQL data files are now the target version
     PGVER=$(sudo cat postgres-data/PG_VERSION)
     if [ "$PGVER" != "${TARGET}" ]; then
-        echo
-        echo "****************************************************************************"
-        echo "Automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} FAILED!"
-        echo "****************************************************************************"
-        echo
+        banner '*' "Standard automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} FAILED!"
         FAILURE=1
     else
-        echo
-        echo "*******************************************************************************"
-        echo "Automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} SUCCEEDED!"
-        echo "*******************************************************************************"
-        echo
+        banner '*' "Standard automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} SUCCEEDED!"
     fi
 
-    # Shut down containers from previous test runs
+    # Shut down any containers that are still running
+    docker compose -f docker-compose-pgauto.yml down --remove-orphans
+
+    # Delete the upgraded PostgreSQL data directory
+    sudo rm -rf postgres-data
+
+    ##
+    ## Tests for one shot mode
+    ##
+    banner '-' "Testing 'one shot' automatic upgrade mode for PostgreSQL ${VERSION} to ${TARGET}"
+
+    # Create the PostgreSQL database using a specific version of PostgreSQL
+    docker compose -f "docker-compose-pg${VERSION}.yml" run --rm server create_db
+
+    # Shut down all of the containers
+    docker compose -f "docker-compose-pg${VERSION}.yml" down --remove-orphans
+
+    # Run the PostgreSQL container in one shot mode
+    TARGET_TAG="${TARGET}-${FLAVOR}" docker compose -f docker-compose-pgauto.yml run --rm -e PGAUTO_ONESHOT=yes postgres
+
+    # Verify the PostgreSQL data files are now the target version
+    PGVER=$(sudo cat postgres-data/PG_VERSION)
+    if [ "$PGVER" != "${TARGET}" ]; then
+        banner '*' "'One shot' automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} FAILED!"
+        FAILURE=1
+    else
+        banner '*' "'One shot' automatic upgrade of PostgreSQL from version ${VERSION} to ${TARGET} SUCCEEDED!"
+    fi
+
+    # Shut down any containers that are still running
     docker compose -f docker-compose-pgauto.yml down
 
     # If running on CI, delete the Postgres Docker image to avoid space problems
@@ -76,12 +111,8 @@ done
 
 # Check for failure
 if [ "${FAILURE}" -ne 0 ]; then
-    echo
-    echo "FAILURE: Automatic upgrade of PostgreSQL failed in one of the tests. Please investigate."
-    echo
+    banner ' ' "FAILURE: Automatic upgrade of PostgreSQL failed in one of the tests. Please investigate."
     exit 1
 else
-    echo
-    echo "SUCCESS: Automatic upgrade testing of PostgreSQL to all versions up to $PGTARGET passed without issue."
-    echo
+    banner ' ' "SUCCESS: Automatic upgrade testing of PostgreSQL to all versions up to $PGTARGET passed without issue."
 fi
diff --git a/test/docker-compose-pg10.yml b/test/docker-compose-pg10.yml
index 5736de3..1517d4e 100644
--- a/test/docker-compose-pg10.yml
+++ b/test/docker-compose-pg10.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg11.yml b/test/docker-compose-pg11.yml
index 5983813..3037db5 100644
--- a/test/docker-compose-pg11.yml
+++ b/test/docker-compose-pg11.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg12.yml b/test/docker-compose-pg12.yml
index b76b1e1..f8a7459 100644
--- a/test/docker-compose-pg12.yml
+++ b/test/docker-compose-pg12.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg13.yml b/test/docker-compose-pg13.yml
index 63f5331..d854e70 100644
--- a/test/docker-compose-pg13.yml
+++ b/test/docker-compose-pg13.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg14.yml b/test/docker-compose-pg14.yml
index 039d12a..94d982a 100644
--- a/test/docker-compose-pg14.yml
+++ b/test/docker-compose-pg14.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg15.yml b/test/docker-compose-pg15.yml
index ac73007..0cc83d2 100644
--- a/test/docker-compose-pg15.yml
+++ b/test/docker-compose-pg15.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg16.yml b/test/docker-compose-pg16.yml
index 2f29927..96e0bed 100644
--- a/test/docker-compose-pg16.yml
+++ b/test/docker-compose-pg16.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg9.5.yml b/test/docker-compose-pg9.5.yml
index dd37bd7..92ad396 100644
--- a/test/docker-compose-pg9.5.yml
+++ b/test/docker-compose-pg9.5.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pg9.6.yml b/test/docker-compose-pg9.6.yml
index ee2db83..228e5f6 100644
--- a/test/docker-compose-pg9.6.yml
+++ b/test/docker-compose-pg9.6.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on:
diff --git a/test/docker-compose-pgauto.yml b/test/docker-compose-pgauto.yml
index 495903c..f3cb600 100644
--- a/test/docker-compose-pgauto.yml
+++ b/test/docker-compose-pgauto.yml
@@ -1,4 +1,3 @@
-version: "2.1"
 x-redash-service: &redash-service
   image: redash/redash:10.1.0.b50633
   depends_on: