Add test to check if smartctl-exporter snap is being installed

tests/functional/test_charm.py

@@ -262,6 +262,19 @@ async def test_redfish_client_timeout_config(self, app, unit, ops_test, provided
         assert config["redfish_client_timeout"] == int(new_timeout)
 
         await app.reset_config(["collect-timeout"])
+
+    async def test_smarctl_exporter_snap_available(self, ops_test, app, unit):
+        """Test if smartctl exporter snap is installed and ranning on the unit."""
+        snap_name = "smartctl-exporter"
+        cmd = f"snap list {snap_name}"
+        results = await run_command_on_unit(ops_test, unit.name, cmd)
+        assert results.get("return-code") == 0
+        assert snap_name in results.get("stdout").strip()
+
+        check_active_cmd = "systemctl is-active snap.smartctl-exporter.smartctl-exporter"
+        results = await run_command_on_unit(ops_test, unit.name, check_active_cmd)
+        assert results.get("return-code") == 0
+        assert results.get("stdout").strip() == "active"
 
     async def test_metrics_available(self, app, unit, ops_test):
         """Test if metrics are available at the expected endpoint on unit."""