test: Retry asserting number of Finit children for a while

Signed-off-by: Jacques de Laval <jacques@de-laval.se>

test/test_start_stop_service/test.sh

@@ -2,6 +2,11 @@
 
 set -eu
 
+assert_num_children() {
+    texec ps -opid,ppid,args
+    assert "$1 services are running" "$(texec pgrep -P 1 | wc -l)" -eq "$1"
+}
+
 # Test
 say 'Set up a service'
 cp "$TEST_DIR"/service.sh test_root/bin
@@ -10,20 +15,16 @@ texec sh -c "echo 'service [2345] kill:20 log /bin/service.sh' > $FINIT_CONF"
 
 say 'Reload Finit'
 texec kill -SIGHUP 1
-sleep 1
 
-service_pids=$(texec pgrep -P 1 | wc -l)
-assert 'One service is running' "$service_pids" -eq 1
+retry 'assert_num_children 1'
 
 say 'Remove the service'
 texec sh -c "echo > $FINIT_CONF"
 
 say 'Reload Finit'
 texec kill -SIGHUP 1
-sleep 1
 
-service_pids=$(texec pgrep -P 1 | wc -l)
-assert 'Zero services are running' "$service_pids" -eq 0
+retry 'assert_num_children 0'
 
 # Teardown
 rm -f test_root/bin/service.sh