diff --git a/testdefs.sh b/testdefs.sh
index c5f68ef6..64768d1b 100644
--- a/testdefs.sh
+++ b/testdefs.sh
@@ -402,7 +402,8 @@ servald_restful_http_server_started() {
 # Utility function:
 #  - fetch the daemon's HTTP server port number
 get_servald_http_server_port() {
-   push_and_set_instance $2 || return $?
+   local _instance="$2"
+   [ -z "$_instance" ] || push_and_set_instance $_instance || return $?
    local _var="$1"
    local _port=$(<"$SERVALINSTANCE_PATH/proc/http_port")
    assert --message="instance $instance_name HTTP server port number is known" [ -n "$_port" ]
@@ -410,7 +411,7 @@ get_servald_http_server_port() {
       eval "$_var=\$_port"
       tfw_log "$_var=$_port"
    fi
-   pop_instance
+   [ -z "$_instance" ] || pop_instance
    return 0
 }
 
diff --git a/testdefs_meshms.sh b/testdefs_meshms.sh
index a4298bb6..609b3b34 100644
--- a/testdefs_meshms.sh
+++ b/testdefs_meshms.sh
@@ -20,6 +20,46 @@ meshms_create_message() {
    create_file --label="$1" - $2 | sed -e '/^$/d'
 }
 
+MESHMS_USE_RESTFUL=false
+
+meshms_use_restful() {
+   setup_curl 7
+   MESHMS_USE_RESTFUL=true
+   MESHMS_RESTFUL_USER="$1"
+   MESHMS_RESTFUL_PASSWORD="$2"
+   get_servald_restful_http_server_port MESHMS_RESTFUL_PORT
+}
+
+meshms_list_messages() {
+   local sid_sender=${1?}
+   local sid_recipient=${2?}
+   if $MESHMS_USE_RESTFUL; then
+      executeOk curl \
+            --silent --fail --show-error \
+            --output meshms_list_messages.json \
+            --basic --user "$MESHMS_RESTFUL_USER:$MESHMS_RESTFUL_PASSWORD" \
+            "http://$addr_localhost:$MESHMS_RESTFUL_PORT/restful/meshms/$sid_sender/$sid_recipient/messagelist.json"
+   else
+      executeOk_servald meshms list messages $sid_sender $sid_recipient
+   fi
+}
+
+meshms_send_message() {
+   local sid_sender=${1?}
+   local sid_recipient=${2?}
+   local text="${3?}"
+   if $MESHMS_USE_RESTFUL; then
+      executeOk curl \
+            --silent --fail --show-error \
+            --output meshms_send_message.json \
+            --basic --user "$MESHMS_RESTFUL_USER:$MESHMS_RESTFUL_PASSWORD" \
+            --form "message=$text;type=text/plain;charset=utf-8" \
+            "http://$addr_localhost:$MESHMS_RESTFUL_PORT/restful/meshms/$sid_sender/$sid_recipient/sendmessage"
+   else
+      executeOk_servald meshms send message $sid_sender $sid_recipient "$text"
+   fi
+}
+
 # Add a sequence of messages of varying sizes up to 1 KiB.
 meshms_add_messages() {
    local sid1="${1?}"
@@ -48,19 +88,19 @@ meshms_add_messages() {
       case $sym in
       '>')
          MESSAGE[$n]=">"
-         executeOk_servald meshms send message $sid1 $sid2 "${TEXT[$n]}"
+         meshms_send_message $sid1 $sid2 "${TEXT[$n]}"
          let ++sent_since_ack
          let ++NSENT
          ;;
       '<')
          MESSAGE[$n]="<"
-         executeOk_servald meshms send message $sid2 $sid1 "${TEXT[$n]}"
+         meshms_send_message $sid2 $sid1 "${TEXT[$n]}"
          let ++NRECV
          ;;
       'A')
          MESSAGE[$n]=ACK
          [ $i -ne 0 -a $sent_since_ack -eq 0 ] && error "two ACKs in a row (at position $i)"
-         executeOk_servald meshms list messages $sid2 $sid1
+         meshms_send_messages $sid2 $sid1
          let ++NACK
          ;;
       *)
diff --git a/tests/meshmsjava b/tests/meshmsjava
index 28739d04..fc1078b9 100755
--- a/tests/meshmsjava
+++ b/tests/meshmsjava
@@ -199,9 +199,13 @@ doc_MeshmsListMessagesNewSinceArrival="Java API list newly arriving MeshMS messa
 setup_MeshmsListMessagesNewSinceArrival() {
    set_extra_config() {
       executeOk_servald config set api.restful.newsince_timeout 360s \
-                               set api.restful.newsince_poll_ms 1000
+                               set api.restful.newsince_poll_ms 1000 \
+                               set api.restful.users.harry.password potter
    }
    setup
+   # Use REST interface to send messages, not CLI, in order to avoid a database
+   # locking storm
+   meshms_use_restful harry potter
    meshms_add_messages $SIDA1 $SIDA2 '><>A>'
    let NROWS=NSENT+NRECV+(NACK?1:0)
    executeJavaOk org.servalproject.test.Meshms meshms-list-messages "$SIDA1" "$SIDA2"
diff --git a/tests/meshmsrestful b/tests/meshmsrestful
index 9da566aa..4453463c 100755
--- a/tests/meshmsrestful
+++ b/tests/meshmsrestful
@@ -350,6 +350,9 @@ setup_MeshmsListMessagesNewSinceArrival() {
                                set api.restful.newsince_poll_ms 1000
    }
    setup
+   # Use REST interface to send messages, not CLI, in order to avoid a database
+   # locking storm
+   meshms_use_restful harry potter
    meshms_add_messages $SIDA1 $SIDA2 '><>A>'
    let NROWS=NSENT+NRECV+(NACK?1:0)
    executeOk curl \