test(sensors-*): add --test hooks and fixture-based unit tests

The three `sensors-*` plugins talk to `psutil.sensors_*()` directly
instead of parsing a shell command, so they previously had no
fixture-based tests. Give each a `--test` hook that loads the return
value from a JSON fixture mirroring psutil's shape:

  sensors-battery      {"percent": ..., "secsleft": ..., "power_plugged": ...}
                        or `null` for "no battery installed"
  sensors-fans         {"<group>": [{"label": ..., "current": ...}]}
  sensors-temperatures {"<group>": [{"label": ..., "current": ...,
                                     "high": ..., "critical": ...}]}

Each plugin gains a declarative `TESTS` list that exercises the
obvious nominal / warn / crit / no-sensors cases plus a few edge
cases inspired by psutil's own test suite
(`tests/test_linux.py::TestSensors*`):

- sensors-battery: `power_plugged = None`, `secsleft = -1`
  (POWER_TIME_UNKNOWN)
- sensors-temperatures: the `coretemp-and-acpitz-nominal` fixture
  mixes sensors with and without threshold metadata

Real host captures also ship as additional fixtures so the suite
exercises real-world quirks the synthetic data would miss:

- sensors-temperatures `dell-laptop-real-capture`: nvme reports
  `high = critical = 65261.85` (kelvin 65535 minus 273.15, a
  "no threshold configured" sentinel) and `dell_ddv` reports
  `high = 0.0` for the same reason.
- sensors-temperatures `coolermaster-real-capture`: two acpitz
  zones plus `coretemp` Package + 6 cores, all nominal.
- sensors-fans `dell-laptop-real-capture`: labelled `dell_ddv` fans
  plus the unlabelled `dell_smm` re-exposure of the same data.
- sensors-fans `coolermaster-real-capture`: the "no fans detected"
  branch on a fanless desktop.
- sensors-battery `dell-laptop-real-capture`: 79 % plugged in and
  charging.
- sensors-battery `coolermaster-real-capture`: the "no battery
  installed" branch on a desktop.

Two related fixes to the plugins:

- **sensors-temperatures**: `_sanitize_threshold()` now rejects
  sentinel "no threshold" values reported by real hardware:
  `None`, `<= 0`, or above 200 C. Both the Dell `dell_ddv` zero and
  the NVMe 65261.85 kelvin-overflow value used to trip the plugin
  into STATE_WARN on any real host that runs those drivers; now
  both are silently ignored and only real thresholds drive state.
  Also bumps `__version__`.
- **sensors-battery**: the message string now ends with the state
  marker (`[WARNING]` / `[CRITICAL]`), matching what sensors-fans
  and sensors-temperatures already do per entry.

Author: markuslf

…n-client-list/unit-test/stdout/EXAMPLE01 …unit-test/stdout/five-clients-four-userscheck-plugins/openvpn-client-list/unit-test/stdout/EXAMPLE01 renamed to check-plugins/openvpn-client-list/unit-test/stdout/five-clients-four-users check-plugins/openvpn-client-list/unit-test/stdout/EXAMPLE01 renamed to check-plugins/openvpn-client-list/unit-test/stdout/five-clients-four-users

@@ -11,11 +11,13 @@
 """See the check's README for more details."""
 
 import argparse
+import json
 import sys
 
 import lib.args
 import lib.base
 import lib.human
+import lib.lftest
 from lib.globals import STATE_OK, STATE_UNKNOWN
 
 try:
@@ -24,9 +26,21 @@ except ImportError:
     print('Python module "psutil" is not installed.')
     sys.exit(STATE_UNKNOWN)
 
+# psutil 5.x exposes sbattery under psutil._common, psutil 6+ under
+# psutil._ntuples. Fall back to a plain namedtuple if neither is
+# available.
+try:
+    from psutil._ntuples import sbattery
+except ImportError:
+    try:
+        from psutil._common import sbattery
+    except ImportError:
+        from collections import namedtuple
+        sbattery = namedtuple('sbattery', ['percent', 'secsleft', 'power_plugged'])
+
 
 __author__ = 'Linuxfabrik GmbH, Zurich/Switzerland'
-__version__ = '2026040801'
+__version__ = '2026041301'
 
 DESCRIPTION = """Reports battery status information including charge percentage, time remaining, and
 power source (AC or battery). Returns OK if no battery is installed or if metrics
@@ -64,6 +78,13 @@ def parse_args():
         default=DEFAULT_CRIT,
     )
 
+    parser.add_argument(
+        '--test',
+        help=lib.args.help('--test'),
+        dest='TEST',
+        type=lib.args.csv,
+    )
+
     parser.add_argument(
         '-w',
         '--warning',
@@ -77,6 +98,21 @@ def parse_args():
     return args
 
 
+def _load_battery_fixture(raw_json):
+    """Convert a test fixture into the shape that `psutil.sensors_battery()`
+    returns: an `sbattery(percent, secsleft, power_plugged)` namedtuple,
+    or `None` if the fixture represents "no battery installed".
+    """
+    data = json.loads(raw_json)
+    if data is None:
+        return None
+    return sbattery(
+        percent=data['percent'],
+        secsleft=data.get('secsleft', -2),  # psutil.POWER_TIME_UNLIMITED == -2
+        power_plugged=data.get('power_plugged'),
+    )
+
+
 def main():
     """The main function. This is where the magic happens."""
 
@@ -86,11 +122,15 @@ def main():
     except SystemExit:
         sys.exit(STATE_UNKNOWN)
 
-    if not hasattr(psutil, 'sensors_battery'):
+    if args.TEST is None and not hasattr(psutil, 'sensors_battery'):
         lib.base.cu('Platform not supported.')
 
     # fetch data
-    batt = psutil.sensors_battery()
+    if args.TEST is None:
+        batt = psutil.sensors_battery()
+    else:
+        stdout, _, _ = lib.lftest.test(args.TEST)
+        batt = _load_battery_fixture(stdout)
     if batt is None:
         lib.base.oao('No battery installed.', STATE_OK, always_ok=args.ALWAYS_OK)
 
@@ -121,6 +161,7 @@ def main():
         _min=0,
     )
     state = lib.base.get_state(batt.percent, args.WARN, args.CRIT, 'le')
+    msg += lib.base.state2str(state, prefix=' ')
 
     # over and out
     lib.base.oao(msg, state, perfdata, always_ok=args.ALWAYS_OK)

check-plugins/sensors-battery/sensors-battery

@@ -0,0 +1,108 @@
+#!/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
+
+import sys
+sys.path.insert(0, '..')
+
+import unittest
+
+from lib.globals import STATE_CRIT, STATE_OK, STATE_WARN
+import lib.lftest
+
+
+# The sensors-battery plugin calls `psutil.sensors_battery()` directly.
+# `--test` reads a JSON fixture that mirrors psutil's return shape:
+#
+#     null                                      (no battery installed)
+#     {"percent": <float>, "secsleft": <int>,   (battery present; -2
+#      "power_plugged": <bool>}                 means POWER_TIME_UNLIMITED)
+TESTS = [
+    {
+        'id': 'ok-no-battery',
+        'test': 'stdout/no-battery,,0',
+        'assert-retc': STATE_OK,
+        'assert-in': ['No battery installed.'],
+    },
+    {
+        'id': 'ok-plugged-in-charging',
+        'test': 'stdout/plugged-in-charging,,0',
+        'assert-retc': STATE_OK,
+        'assert-in': ['65.5%', 'plugged in and charging'],
+    },
+    {
+        'id': 'ok-plugged-in-full',
+        'test': 'stdout/plugged-in-full,,0',
+        'assert-retc': STATE_OK,
+        'assert-in': ['100.0%', 'plugged in and fully charged'],
+    },
+    {
+        'id': 'warn-discharging-15-percent',
+        'test': 'stdout/discharging-15-percent,,0',
+        'params': '--warning 20 --critical 5',
+        'assert-retc': STATE_WARN,
+        'assert-in': ['15.0%', 'not plugged in and discharging', '[WARNING]'],
+    },
+    {
+        'id': 'crit-discharging-3-percent',
+        'test': 'stdout/discharging-3-percent,,0',
+        'params': '--warning 20 --critical 5',
+        'assert-retc': STATE_CRIT,
+        'assert-in': ['3.0%', 'not plugged in and discharging', '[CRITICAL]'],
+    },
+    {
+        'id': 'ok-always-ok-masks-crit',
+        'test': 'stdout/discharging-3-percent,,0',
+        'params': '--warning 20 --critical 5 --always-ok',
+        'assert-retc': STATE_OK,
+        'assert-in': ['3.0%'],
+    },
+    {
+        # Real capture from a Dell XPS laptop plugged into AC, 79%.
+        'id': 'ok-dell-laptop-real-capture',
+        'test': 'stdout/dell-laptop-real-capture,,0',
+        'assert-retc': STATE_OK,
+        'assert-in': ['79.27%', 'plugged in and charging'],
+    },
+    {
+        # Edge case from psutil's own tests: the AC/online file is
+        # missing and /BAT0/status returns an unparseable value, so
+        # power_plugged comes back as None. secsleft is also unknown
+        # (POWER_TIME_UNKNOWN == -1). The plugin currently reports
+        # the percent and falls through the "not plugged" branch.
+        'id': 'warn-power-plugged-undetermined',
+        'test': 'stdout/power-plugged-undetermined,,0',
+        'params': '--warning 50 --critical 20',
+        'assert-retc': STATE_WARN,
+        'assert-in': ['42.0%', '[WARNING]'],
+    },
+    {
+        # Real capture from a "Cooler Master" desktop: psutil returns
+        # None for sensors_battery() and the plugin emits the
+        # "No battery installed." branch.
+        'id': 'ok-coolermaster-real-capture',
+        'test': 'stdout/coolermaster-real-capture,,0',
+        'assert-retc': STATE_OK,
+        'assert-in': ['No battery installed.'],
+    },
+]
+
+
+class TestCheck(unittest.TestCase):
+
+    check = '../sensors-battery'
+
+    def test(self):
+        for t in TESTS:
+            with self.subTest(id=t['id']):
+                lib.lftest.run(self, self.check, t)
+
+
+if __name__ == '__main__':
+    unittest.main()

check-plugins/sensors-battery/unit-test/run

@@ -0,0 +1 @@
+null

check-plugins/sensors-battery/unit-test/stdout/coolermaster-real-capture

@@ -0,0 +1 @@
+{"percent": 79.26515930113052, "secsleft": -2, "power_plugged": true}

check-plugins/sensors-battery/unit-test/stdout/dell-laptop-real-capture

@@ -0,0 +1 @@
+{"percent": 15.0, "secsleft": 2400, "power_plugged": false}

check-plugins/sensors-battery/unit-test/stdout/discharging-15-percent

@@ -0,0 +1 @@
+{"percent": 3.0, "secsleft": 420, "power_plugged": false}

check-plugins/sensors-battery/unit-test/stdout/discharging-3-percent

@@ -0,0 +1 @@
+null

check-plugins/sensors-battery/unit-test/stdout/no-battery

@@ -0,0 +1 @@
+{"percent": 65.5, "secsleft": -2, "power_plugged": true}

check-plugins/sensors-battery/unit-test/stdout/plugged-in-charging

@@ -0,0 +1 @@
+{"percent": 100.0, "secsleft": -2, "power_plugged": true}