test(mysql-storage-engines): add happy-path container test against MariaDB 10.11

Spin up quay.io/sclorg/mariadb-1011-c10s, seed the `test` database
with one empty InnoDB table so the plugin sees the default storage
engine in use (otherwise it warns "InnoDB is enabled but isn't
being used"), then run the plugin from the host and assert
STATE_OK + "Everything is ok.".

Author: markuslf

check-plugins/mysql-storage-engines/unit-test/run

@@ -0,0 +1,126 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8; py-indent-offset: 4 -*-
+#
+# Author:  Linuxfabrik GmbH, Zurich, Switzerland
+# Contact: info (at) linuxfabrik (dot) ch
+#          https://www.linuxfabrik.ch/
+# License: The Unlicense, see LICENSE file.
+
+# https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CONTRIBUTING.md
+
+"""Integration tests for the mysql-storage-engines check plugin.
+
+The plugin opens a real `pymysql` connection and introspects
+`information_schema.tables`, `SHOW ENGINES`, `SHOW VARIABLES` and
+`SHOW DATABASES`, so a static fixture cannot drive it - we spin up
+an actual MariaDB server and let the plugin talk to it over TCP.
+
+Container source: `quay.io/sclorg/mariadb-1011-c10s` - the Red Hat /
+CentOS Stream 10 sclorg packaging of MariaDB 10.11 LTS.
+
+Per CONTRIBUTING's "Combine container tests with fixtures" rule,
+this file holds only the happy-path integration test. We seed the
+container's `test` DB with one empty InnoDB table so the plugin sees
+at least one table on the default engine - otherwise it would warn
+"InnoDB is enabled but isn't being used. Add skip-innodb to ...".
+
+Requirements:
+- podman (or docker) with a reachable socket
+- `pip install testcontainers`
+- `tools/run-unit-tests` auto-sets `CONTAINER_HOST` and
+  `TESTCONTAINERS_RYUK_DISABLED`
+"""
+
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+
+sys.path.insert(0, '..')
+
+import lib.lftest
+from lib.globals import STATE_OK
+
+
+IMAGES = [
+    ('quay.io/sclorg/mariadb-1011-c10s', 'MariaDB 10.11'),
+]
+
+
+class TestCheck(unittest.TestCase):
+    pass
+
+
+def _check_image(test, image_pair):
+    image, label = image_pair
+    print(f'\n=== Testing {label} ({image}) ===', flush=True)
+    with lib.lftest.run_container(
+        image,
+        env={
+            'MYSQL_ROOT_PASSWORD': 'test',
+            'MYSQL_USER': 'test',
+            'MYSQL_PASSWORD': 'test',
+            'MYSQL_DATABASE': 'test',
+        },
+        ports=[3306],
+        command='run-mysqld --port=3306',
+        wait_log='port: 3306',
+        wait_log_timeout=180,
+    ) as container:
+        host = container.get_container_host_ip()
+        port = container.get_exposed_port(3306)
+
+        # Seed an empty InnoDB table so the plugin sees the default
+        # storage engine "in use" and does not warn about it.
+        container.exec([
+            'sh', '-c',
+            'mysql -utest -ptest test -e '
+            '"CREATE TABLE seed_innodb (id INT PRIMARY KEY) ENGINE=InnoDB"',
+        ])
+
+        with tempfile.NamedTemporaryFile(
+            mode='w',
+            suffix='.cnf',
+            delete=False,
+        ) as cnf:
+            cnf.write(
+                f'[client]\n'
+                f'host={host}\n'
+                f'port={port}\n'
+                f'user=test\n'
+                f'password=test\n'
+                f'database=test\n'
+            )
+            defaults_file = cnf.name
+
+        try:
+            cmd = [
+                'python3', '../mysql-storage-engines',
+                f'--defaults-file={defaults_file}',
+            ]
+            print(f'Run plugin: {" ".join(cmd)}', flush=True)
+            result = subprocess.run(
+                cmd,
+                cwd=os.path.dirname(os.path.abspath(__file__)),
+                capture_output=True,
+                text=True,
+            )
+        finally:
+            os.unlink(defaults_file)
+
+        combined = result.stdout + result.stderr
+        print(f'Script output:\n{combined.strip()}', flush=True)
+
+        # A freshly booted server has no user tables, so the plugin
+        # finds no fragmented tables, no auto-increment hotspots and
+        # no unused storage engines to recommend disabling.
+        test.assertEqual(result.returncode, STATE_OK)
+        test.assertIn('Everything is ok.', combined)
+
+
+lib.lftest.attach_each(TestCheck, IMAGES, _check_image, id_func=lambda it: it[1])
+
+
+if __name__ == '__main__':
+    unittest.main()