diff --git a/src/machine/machine-varlink.c b/src/machine/machine-varlink.c
index 8f0e4f9363..3affc5265c 100644
--- a/src/machine/machine-varlink.c
+++ b/src/machine/machine-varlink.c
@@ -236,6 +236,8 @@ int lookup_machine_by_name_or_pid(sd_varlink *link, Manager *manager, const char
         assert(manager);
         assert(ret_machine);
 
+        /* This returns 0 on success, 1 on error and it is replied, and a negative errno otherwise. */
+
         if (machine_name) {
                 r = lookup_machine_by_name(link, manager, machine_name, &machine);
                 if (r == -EINVAL)
@@ -340,7 +342,7 @@ int vl_method_kill(sd_varlink *link, sd_json_variant *parameters, sd_varlink_met
         r = lookup_machine_by_name_or_pid(link, manager, p.machine_name, p.pid, &machine);
         if (r == -ESRCH)
                 return sd_varlink_error(link, "io.systemd.Machine.NoSuchMachine", NULL);
-        if (r < 0)
+        if (r != 0)
                 return r;
 
         if (isempty(p.swhom))
diff --git a/src/machine/machined-varlink.c b/src/machine/machined-varlink.c
index b43f586587..536aee507d 100644
--- a/src/machine/machined-varlink.c
+++ b/src/machine/machined-varlink.c
@@ -448,7 +448,7 @@ static int vl_method_list(sd_varlink *link, sd_json_variant *parameters, sd_varl
                 r = lookup_machine_by_name_or_pid(link, m, p.machine_name, p.pid, &machine);
                 if (r == -ESRCH)
                         return sd_varlink_error(link, "io.systemd.Machine.NoSuchMachine", NULL);
-                if (r < 0)
+                if (r != 0)
                         return r;
 
                 return list_machine_one(link, machine, /* more= */ false);
@@ -496,7 +496,7 @@ static int lookup_machine_and_call_method(sd_varlink *link, sd_json_variant *par
         r = lookup_machine_by_name_or_pid(link, manager, p.machine_name, p.pid, &machine);
         if (r == -ESRCH)
                 return sd_varlink_error(link, "io.systemd.Machine.NoSuchMachine", NULL);
-        if (r < 0)
+        if (r != 0)
                 return r;
 
         return method(link, parameters, flags, machine);
@@ -561,7 +561,8 @@ static int vl_method_list_images(sd_varlink *link, sd_json_variant *parameters,
         struct params {
                 const char *image_name;
                 bool acquire_metadata;
-        };
+        } p = {};
+        int r;
 
         static const sd_json_dispatch_field dispatch_table[] = {
                 { "name",            SD_JSON_VARIANT_STRING,    sd_json_dispatch_const_string, offsetof(struct params, image_name),        0 },
@@ -570,11 +571,6 @@ static int vl_method_list_images(sd_varlink *link, sd_json_variant *parameters,
                 {}
         };
 
-        _cleanup_hashmap_free_ Hashmap *images = NULL;
-        struct params p = {};
-        Image *image;
-        int r;
-
         assert(link);
         assert(parameters);
 
@@ -583,22 +579,24 @@ static int vl_method_list_images(sd_varlink *link, sd_json_variant *parameters,
                 return r;
 
         if (p.image_name) {
+                _cleanup_(image_unrefp) Image *found = NULL;
+
                 if (!image_name_is_valid(p.image_name))
                         return sd_varlink_error_invalid_parameter_name(link, "name");
 
-                r = image_find(IMAGE_MACHINE, p.image_name, /* root = */ NULL, &image);
+                r = image_find(IMAGE_MACHINE, p.image_name, /* root = */ NULL, &found);
                 if (r == -ENOENT)
                         return sd_varlink_error(link, "io.systemd.MachineImage.NoSuchImage", NULL);
                 if (r < 0)
                         return log_debug_errno(r, "Failed to find image: %m");
 
-                return list_image_one_and_maybe_read_metadata(link, image, /* more = */ false, p.acquire_metadata);
+                return list_image_one_and_maybe_read_metadata(link, found, /* more = */ false, p.acquire_metadata);
         }
 
         if (!FLAGS_SET(flags, SD_VARLINK_METHOD_MORE))
                 return sd_varlink_error(link, SD_VARLINK_ERROR_EXPECTED_MORE, NULL);
 
-        images = hashmap_new(&image_hash_ops);
+        _cleanup_hashmap_free_ Hashmap *images = hashmap_new(&image_hash_ops);
         if (!images)
                 return -ENOMEM;
 
@@ -606,7 +604,7 @@ static int vl_method_list_images(sd_varlink *link, sd_json_variant *parameters,
         if (r < 0)
                 return log_debug_errno(r, "Failed to discover images: %m");
 
-        Image *previous = NULL;
+        Image *image, *previous = NULL;
         HASHMAP_FOREACH(image, images) {
                 if (previous) {
                         r = list_image_one_and_maybe_read_metadata(link, previous, /* more = */ true, p.acquire_metadata);
diff --git a/test/units/TEST-13-NSPAWN.machined.sh b/test/units/TEST-13-NSPAWN.machined.sh
index 92daf70acf..987ecfee90 100755
--- a/test/units/TEST-13-NSPAWN.machined.sh
+++ b/test/units/TEST-13-NSPAWN.machined.sh
@@ -12,7 +12,7 @@ export PAGER=
 at_exit() {
     set +e
 
-    machinectl status long-running >/dev/null && machinectl kill --signal=KILL long-running
+    machinectl status long-running &>/dev/null && machinectl kill --signal=KILL long-running
     mountpoint -q /var/lib/machines && timeout 10 sh -c "until umount /var/lib/machines; do sleep .5; done"
     [[ -n "${NSPAWN_FRAGMENT:-}" ]] && rm -f "/etc/systemd/nspawn/$NSPAWN_FRAGMENT" "/var/lib/machines/$NSPAWN_FRAGMENT"
     rm -f /run/systemd/nspawn/*.nspawn
@@ -60,11 +60,13 @@ EOF
 
 long_running_machine_start() {
     # shellcheck disable=SC2015
-    machinectl status long-running >/dev/null && return 0 || true
+    machinectl status long-running &>/dev/null && return 0 || true
+
+    # Ensure the service stopped.
+    systemctl stop systemd-nspawn@long-running.service 2>/dev/null || :
 
     rm -f /var/lib/machines/long-running/ready
-    # sometime `machinectl start` returns 1 and then do a success
-    machinectl start long-running || machinectl start long-running
+    machinectl start long-running
     # !!!! DO NOT REMOVE THIS TEST
     # The test makes sure that the long-running's init script has enough time to start and registered signal traps
     timeout 30 bash -c "until test -e /var/lib/machines/long-running/ready; do sleep .5; done"
@@ -120,7 +122,7 @@ timeout 10 bash -c "until test -e /var/lib/machines/long-running/reboot; do slee
 rm -f /var/lib/machines/long-running/terminate
 machinectl terminate long-running
 timeout 10 bash -c "until test -e /var/lib/machines/long-running/terminate; do sleep .5; done"
-timeout 10 bash -c "while machinectl status long-running; do sleep .5; done"
+timeout 10 bash -c "while machinectl status long-running &>/dev/null; do sleep .5; done"
 # Restart container
 long_running_machine_start
 # Test for 'machinectl kill'
@@ -261,11 +263,11 @@ varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List
 
 pid=$(varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List '{"name":"long-running"}' | jq '.leader.pid')
 varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List '{"name":"long-running"}' >/tmp/expected
-varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List "{\"pid\":$pid}" >/tmp/got
-diff -u /tmp/expected /tmp/got
-
-varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List "{\"name\":\"long-running\", \"pid\":$pid}"
+varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List "{\"pid\":$pid}" | diff /tmp/expected -
+varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List "{\"name\":\"long-running\", \"pid\":$pid}" | diff /tmp/expected -
 (! varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List "{\"name\":\"non-existent\", \"pid\":$pid}")
+(! varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List '{"name":""}')
+(! varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List '{"name":"ah@??.hmm"}')
 
 # test io.systemd.Machine.Kill
 # sending TRAP signal
@@ -273,10 +275,6 @@ rm -f /var/lib/machines/long-running/trap
 varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.Kill '{"name":"long-running", "whom": "leader", "signal": 5}'
 timeout 30 bash -c "until test -e /var/lib/machines/long-running/trap; do sleep .5; done"
 
-# sending KILL signal
-varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.Kill '{"name":"long-running", "signal": 9}'
-timeout 30 bash -c "while varlinkctl call /run/systemd/machine/io.systemd.Machine io.systemd.Machine.List '{\"name\":\"long-running\"}'; do sleep 0.5; done"
-
 # test io.systemd.Machine.Terminate
 long_running_machine_start
 rm -f /var/lib/machines/long-running/terminate