MeshCore-mqtt-observer/test/README.md

Host unit tests

Fast, hardware-free unit tests for the fork's pure logic, run on the host with GoogleTest via PlatformIO's native environment. They cover the extractable observer/WebConfig logic (validation, preset table, topic templates, key parsing) — the parts that don't depend on the ESP32, radio, or network stack. Integration behavior (AsyncTCP transport, WiFi/MQTT, SoftAP) is exercised separately; see "Local testing without hardware" in MQTT_IMPLEMENTATION.md.

Running

pio test -e native                      # all suites
pio test -e native -f test_webconfig_keys   # a single suite

A green [PASSED] per suite means GoogleTest returned 0 (all assertions passed). PlatformIO's "0 test cases" line is just its Unity-style counter and does not reflect the GoogleTest count — run the built binary directly (.pio/build/native/program) to see the per-assertion breakdown.

Suites

Suite	Source under test	Covers
test_mqtt_presets	src/helpers/MQTTPresets.h	preset lookup; table integrity (unique names, non-empty URLs, JWT-audience invariant, names fit the slot buffer); mqttPresetNeedsSlotCredentials; slot-count constants
test_observer_validation	src/helpers/MQTTObserverValidation.h	IATA (exactly 3 alphanumerics), owner key (64 hex), NTP hostname, and the buffer-fit check behind the #17 length validation — including boundaries and nulls
test_webconfig_keys	src/helpers/WebConfigKeys.h	POST-key allowlist, secret detection, admin-password classification/validation, slot-index bounds, and the short-key out-of-bounds guard (attacker-supplied keys)
test_topic_template	src/helpers/MQTTTopicTemplate.h	{iata}/{device}/{token}/{type} expansion, overflow/NUL-termination, and a buffer-size fuzz
test_mqtt_topic_router	src/helpers/MQTTTopicRouter.h	complete preset/custom topic-routing contract; MeshRank all types except raw; required identifiers; invalid inputs/slots; exact buffer boundaries
test_mqtt_connection_policy	src/helpers/MQTTConnectionPolicy.h	reconnect guard/backoff/stagger and breaker transitions; stable reset; JWT lifetime/renewal policy; exact timing boundaries and 32-bit millis() rollover; WiFi current-outage start sticky across STA reconnect attempts
test_alert_fault_policy	src/helpers/AlertFaultPolicy.h	WiFi/MQTT fault edge detector; OutageSnapshot (down / started_ms / initiating reason) fed to tick and formatWifiAlert; reason-8 reconnects change neither duration nor initiating reason; flap between status polls; down at millis()==0; packed 64-bit cross-task word; rate-limit floor and first-fire; 5 s poll cadence and millis() rollover
test_mqtt_packet_queue_policy	src/helpers/MQTTPacketQueuePolicy.h	queue-full eviction; stale-disconnect flush; adaptive drain limits; bounded QoS0 retries; exact timing boundaries and 32-bit millis() rollover
test_mqtt_packet_filter	src/helpers/MQTTPacketFilter.h	per-slot 0-15 allowlist parsing/formatting, numeric and named spellings; exact bounds; membership; candidate/eligible split and retry-completion policy; pre-queue union gate; default-mask detection
test_mqtt_runtime_buffer_lifecycle	src/helpers/MQTTRuntimeBufferLifecycle.h	idempotent allocation/release; partial-allocation degradation; retry of only missing buffers
test_mqtt_prefs_codec	src/helpers/MQTTPrefsStorage.h, src/helpers/MQTTPrefsCodec.h	binary pre-slot/3-slot/6-slot migration fixtures; v1 header integrity; downgrade preservation; shortest-payload write policy (default filters stay downgrade-readable)
test_mqtt_prefs_serializer	src/helpers/MQTTPrefsSerializer.h, src/helpers/ConfigSerializer.*	semantic nested /mqtt.json round trips; numeric slot keys; required/future version handling; strict length/overflow/duplicate rejection; safe semantic repair; scratch-before-live loading
test_mqtt_prefs_atomic_store	src/helpers/MQTTPrefsAtomicStore.h, src/helpers/MQTTPrefsRecovery.h	production JSON begin/write/checksum-finish/schema-verify/commit orchestration; first-migration and rename-boundary recovery; legacy /node_prefs handoff; failure cleanup and original-file preservation
test_mqtt_payload_builder	src/helpers/MQTTPayloadBuilder.cpp	status/packet/raw JSON contracts; optional fields; escaping; RX metrics and path; score handling; exact buffer bounds; maximum representative payloads
test_utils	src/Utils.cpp	Utils::toHex (upstream)

Conventions (and how to add a suite)

• Each test/test_<name>/ directory builds into its own GoogleTest program and must define its own main() (::testing::InitGoogleTest + RUN_ALL_TESTS).
• Tests are host-only: include only pure headers. Arduino/crypto stubs live in test/mocks/ (on the include path via -I test/mocks).
• Firmware headers are included from src (via -I src, e.g. #include "helpers/MQTTPresets.h"). Some are guarded or ESP-flavored, so a suite may need shims before the include — e.g. test_mqtt_presets does #define WITH_MQTT_BRIDGE 1 (the preset table is behind that flag) and #define PROGMEM (the embedded CA-cert strings are PROGMEM-qualified).
• To add a suite: create test/test_<name>/test_<name>.cpp with a main(), and add any host-only source it links to the native env's build_src_filter in platformio.ini (header-only code needs no source entry). No other wiring.
• Keep logic testable by extracting pure functions into headers (as MQTTObserverValidation.h / WebConfigKeys.h / MQTTTopicTemplate.h do) and having the firmware call the same functions.