tests/main/interfaces-process-control: retry check for process being …

…terminated

We are sending a SIGTERM to the test process, and so its handling and test
process termination is asynchronous and there is no guarantee the test process
exits immediately. Retry the check a couple of times to account for this.

The problem was often seen to happen on openSUSE:

Error: 2024-01-17 21:36:40 Error executing google:opensuse-tumbleweed-64:tests/main/interfaces-process-control (jan172104-345478) :
-----
+ echo 'The interface is disconnected by default'
The interface is disconnected by default
+ snap interfaces -i process-control
+ MATCH -- '- +process-control-consumer:process-control'

'snap interfaces' is deprecated; use 'snap connections'.
+ echo 'When the plug is connected'
When the plug is connected
+ snap connect process-control-consumer:process-control
+ echo 'Then the snap is able to kill an existing process'
Then the snap is able to kill an existing process
+ pid=31252
+ sleep 5m
+ kill -s 0 31252
+ process-control-consumer.signal SIGTERM 31252
+ not kill -s 0 31252
-----

Signed-off-by: Maciej Borzecki <[email protected]>

tests/main/interfaces-process-control/task.yaml

@@ -28,7 +28,7 @@ execute: |
     pid=$!
     kill -s 0 "$pid"
     process-control-consumer.signal SIGTERM "$pid"
-    not kill -s 0 "$pid"
+    retry -n 10 not kill -s 0 "$pid"
 
     if [ "$(snap debug confinement)" = partial ] ; then
         exit