Add MQTT monitor with Home Assistant autodiscovery

Poll lifepo4wered-cli every 30s (configurable), publish all registers as
one JSON state payload, and announce sensors/binary sensor via MQTT
discovery. run.sh pulls broker credentials from the Supervisor mqtt
service (Mosquitto addon) with manual overrides in addon options.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/stubs/paho/mqtt/client.py

@@ -0,0 +1,41 @@
+"""Minimal paho-mqtt stand-in for end-to-end smoke tests without a broker.
+
+Every publish is appended to the file named by $STUB_MQTT_LOG as
+"<topic>\t<payload>".
+"""
+
+import os
+
+
+class CallbackAPIVersion:
+    VERSION1 = 1
+    VERSION2 = 2
+
+
+class Client:
+    def __init__(self, *args, **kwargs):
+        self.on_connect = None
+        self._log = open(os.environ["STUB_MQTT_LOG"], "a")
+
+    def username_pw_set(self, username, password=None):
+        pass
+
+    def will_set(self, topic, payload=None, qos=0, retain=False):
+        pass
+
+    def connect(self, host, port=1883, keepalive=60):
+        pass
+
+    def loop_start(self):
+        if self.on_connect:
+            self.on_connect(self, None, {}, 0, None)
+
+    def loop_stop(self):
+        pass
+
+    def disconnect(self):
+        self._log.close()
+
+    def publish(self, topic, payload=None, qos=0, retain=False):
+        self._log.write("%s\t%s\n" % (topic, payload))
+        self._log.flush()

tests/test_monitor.py

@@ -0,0 +1,97 @@
+import json
+import os
+import sys
+import unittest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..",
+                                "hassio-addon-lifepo4wered"))
+
+import lifepo4wered_monitor as mon
+
+
+class ParseOutputTest(unittest.TestCase):
+    def test_parses_sample_output(self):
+        values = mon.parse_cli_output(mon.SAMPLE_OUTPUT)
+        self.assertEqual(values["VIN"], 4709)
+        self.assertEqual(values["VBAT"], 3233)
+        self.assertEqual(values["IOUT"], 1355)
+        self.assertEqual(values["PI_RUNNING"], 1)
+        self.assertEqual(len(values), 36)
+
+    def test_skips_malformed_lines(self):
+        values = mon.parse_cli_output("VIN = 5000\ngarbage line\nVBAT = abc\n")
+        self.assertEqual(values, {"VIN": 5000})
+
+    def test_handles_negative_values(self):
+        values = mon.parse_cli_output("IOUT_OFFSET = -12\n")
+        self.assertEqual(values["IOUT_OFFSET"], -12)
+
+
+class DiscoveryTest(unittest.TestCase):
+    def setUp(self):
+        self.messages = dict(mon.discovery_messages(
+            discovery_prefix="homeassistant",
+            state_topic="lifepo4wered/state",
+            availability_topic="lifepo4wered/availability",
+        ))
+
+    def test_main_voltage_sensor(self):
+        topic = "homeassistant/sensor/lifepo4wered/vin/config"
+        self.assertIn(topic, self.messages)
+        cfg = self.messages[topic]
+        self.assertEqual(cfg["device_class"], "voltage")
+        self.assertEqual(cfg["unit_of_measurement"], "V")
+        self.assertEqual(cfg["state_class"], "measurement")
+        self.assertIn("value_json.VIN", cfg["value_template"])
+        self.assertNotIn("entity_category", cfg)
+
+    def test_current_sensor(self):
+        cfg = self.messages["homeassistant/sensor/lifepo4wered/iout/config"]
+        self.assertEqual(cfg["device_class"], "current")
+        self.assertEqual(cfg["unit_of_measurement"], "A")
+
+    def test_external_power_binary_sensor(self):
+        topic = "homeassistant/binary_sensor/lifepo4wered/external_power/config"
+        self.assertIn(topic, self.messages)
+        cfg = self.messages[topic]
+        self.assertEqual(cfg["device_class"], "power")
+        self.assertIn("VIN_THRESHOLD", cfg["value_template"])
+
+    def test_diagnostic_entities_are_categorized(self):
+        cfg = self.messages["homeassistant/sensor/lifepo4wered/vbat_shdn/config"]
+        self.assertEqual(cfg["entity_category"], "diagnostic")
+        self.assertEqual(cfg["unit_of_measurement"], "V")
+
+    def test_skipped_registers_have_no_entity(self):
+        for key in ("i2c_reg_ver", "dco_rsel", "vbat_offset", "cfg_write"):
+            self.assertNotIn(
+                "homeassistant/sensor/lifepo4wered/%s/config" % key,
+                self.messages)
+
+    def test_common_fields(self):
+        for topic, cfg in self.messages.items():
+            self.assertEqual(cfg["state_topic"], "lifepo4wered/state")
+            self.assertEqual(cfg["availability_topic"],
+                             "lifepo4wered/availability")
+            self.assertTrue(cfg["unique_id"].startswith("lifepo4wered_"),
+                            topic)
+            self.assertEqual(cfg["device"]["identifiers"], ["lifepo4wered_pi"])
+            json.dumps(cfg)  # must be serializable
+
+    def test_unique_ids_are_unique(self):
+        ids = [cfg["unique_id"] for cfg in self.messages.values()]
+        self.assertEqual(len(ids), len(set(ids)))
+
+
+class ReadValuesTest(unittest.TestCase):
+    def test_fake_mode(self):
+        os.environ["LIFEPO4WERED_FAKE"] = "1"
+        try:
+            values = mon.read_values()
+        finally:
+            del os.environ["LIFEPO4WERED_FAKE"]
+        self.assertEqual(values["VOUT"], 4993)
+
+
+if __name__ == "__main__":
+    unittest.main()