Merge pull request juju#18715 from nvinuesa/fix_relation_departing_ci

juju#18715

This patch fixes the relation departing unit CI test that was failing only on AWS.
The reason is that after the patch
juju#18614 the logs are no longer received for the removed unit, making the check on logs impossible for the test to succeed.
The fix was therefore to check the values of the `related-units` field in the yaml output of juju show-unit.

## QA steps

Run (on AWS):

```
$ ./main.sh -c aws relations test_relation_departing_unit
```

## Links


**Jira card:** JUJU-7486

tests/suites/relations/relation_departing_unit.sh

@@ -12,38 +12,30 @@ run_relation_departing_unit() {
 
 	echo "Deploy 2 departer instances"
 	juju deploy ./testcharms/charms/departer -n 2
+
 	wait_for "departer" "$(idle_condition "departer" 0 0)"
 	wait_for "departer" "$(idle_condition "departer" 0 1)"
 
+	check_contains "$(juju show-unit departer/0 | yq '.departer/0.relation-info[0].related-units')" 'departer/1'
+	check_contains "$(juju show-unit departer/1 | yq '.departer/1.relation-info[0].related-units')" 'departer/0'
+
 	echo "Remove departer/1"
 	juju remove-unit departer/1
 
 	attempt=10
 	while [[ ${attempt} -gt 0 ]]; do
 		attempt=$((attempt - 1))
-		sleep 10
+
 		echo "Check departer/1 is departing the relation"
-		got=$(juju debug-log --replay --include unit-departer-0 | grep 'Remote unit departer/1 is departing the relation' || true)
-		if [ -z "${got}" ]; then
-			# shellcheck disable=SC2046
-			echo $(red "expected departer/0 to be notified that departer/1 went away")
-			if [[ ${attempt} -eq 0 ]]; then
-				exit 1
-			else
-				continue
-			fi
-		fi
-		got=$(juju debug-log --replay --include unit-departer-1 | grep 'Local unit is departing the relation' || true)
-		if [ -z "${got}" ]; then
+		got=$(juju show-unit departer/0 | yq '.departer/0.relation-info[0].related-units' || true)
+		if [ "${got}" != null ]; then
 			# shellcheck disable=SC2046
-			echo $(red "expected departer/1 to be notified that it is going away")
+			echo $(red "expected departer/1 to be removed from departer/0 related-units")
 			if [[ ${attempt} -eq 0 ]]; then
 				exit 1
-			else
-				continue
 			fi
 		fi
-		break
+		sleep 2
 	done
 
 	destroy_model "${model_name}"