tests: Add a scenario for alert history feature

This scenario checks that we can retrieve the
cluster alerts from the Loki API.

Refs: #3180

tests/post/features/logging.feature

@@ -20,3 +20,8 @@ Feature: Logging stack is up and running
     And the Loki API is available
     And we have set up a logger pod
     Then we can retrieve logs from logger pod in Loki API
+
+  Scenario: Retrieve cluster alerts from Loki
+    Given the Kubernetes API is available
+    And the Loki API is available
+    Then we can retrieve cluster alerts from Loki API

tests/post/steps/test_logging.py

@@ -161,7 +161,7 @@ def query_log_from_loki(k8s_client, context):
 
 
 @then("we can retrieve logs from logger pod in Loki API")
-def retrieve_pod_logs_from_loki(k8s_client, nodename, pod_creation_ts):
+def retrieve_pod_logs_from_loki(k8s_client, pod_creation_ts):
     query = {
         "query": '{pod="logger"}',
         "start": pod_creation_ts,
@@ -185,6 +185,28 @@ def _check_log_line_exists():
     )
 
 
+@then("we can retrieve cluster alerts from Loki API")
+def retrieve_cluster_alerts_from_loki(k8s_client):
+    query = {
+        "query": '{app="metalk8s-alert-logger"}',
+    }
+
+    def _check_log_line_exists():
+        response = query_loki_api(k8s_client, query, route="query_range")
+        try:
+            result_data = response[0]["data"]["result"][0]["values"]
+        except (IndexError, KeyError):
+            result_data = []
+        assert result_data, "No cluster alerts found in Loki"
+
+    utils.retry(
+        _check_log_line_exists,
+        times=40,
+        wait=5,
+        name="check that cluster alerts are logged in Loki",
+    )
+
+
 # }}}
 
 # Helpers {{{