Merge branch 'dev' into dashboard_dns_lookup_delay

esphome/components/api/api.proto

@@ -27,9 +27,6 @@ service APIConnection {
   rpc subscribe_logs (SubscribeLogsRequest) returns (void) {}
   rpc subscribe_homeassistant_services (SubscribeHomeassistantServicesRequest) returns (void) {}
   rpc subscribe_home_assistant_states (SubscribeHomeAssistantStatesRequest) returns (void) {}
-  rpc get_time (GetTimeRequest) returns (GetTimeResponse) {
-    option (needs_authentication) = false;
-  }
   rpc execute_service (ExecuteServiceRequest) returns (void) {}
   rpc noise_encryption_set_key (NoiseEncryptionSetKeyRequest) returns (NoiseEncryptionSetKeyResponse) {}
 
@@ -809,12 +806,12 @@ message HomeAssistantStateResponse {
 // ==================== IMPORT TIME ====================
 message GetTimeRequest {
   option (id) = 36;
-  option (source) = SOURCE_BOTH;
+  option (source) = SOURCE_SERVER;
 }
 
 message GetTimeResponse {
   option (id) = 37;
-  option (source) = SOURCE_BOTH;
+  option (source) = SOURCE_CLIENT;
   option (no_delay) = true;
 
   fixed32 epoch_seconds = 1;

esphome/components/api/api_connection.cpp

@@ -42,6 +42,8 @@ static constexpr uint8_t MAX_PING_RETRIES = 60;
 static constexpr uint16_t PING_RETRY_INTERVAL = 1000;
 static constexpr uint32_t KEEPALIVE_DISCONNECT_TIMEOUT = (KEEPALIVE_TIMEOUT_MS * 5) / 2;
 
+static constexpr auto ESPHOME_VERSION_REF = StringRef::from_lit(ESPHOME_VERSION);
+
 static const char *const TAG = "api.connection";
 #ifdef USE_CAMERA
 static const int CAMERA_STOP_STREAM = 5000;
@@ -1081,12 +1083,6 @@ void APIConnection::on_get_time_response(const GetTimeResponse &value) {
 }
 #endif
 
-bool APIConnection::send_get_time_response(const GetTimeRequest &msg) {
-  GetTimeResponse resp;
-  resp.epoch_seconds = ::time(nullptr);
-  return this->send_message(resp, GetTimeResponse::MESSAGE_TYPE);
-}
-
 #ifdef USE_BLUETOOTH_PROXY
 void APIConnection::subscribe_bluetooth_le_advertisements(const SubscribeBluetoothLEAdvertisementsRequest &msg) {
   bluetooth_proxy::global_bluetooth_proxy->subscribe_api_connection(this, msg.flags);
@@ -1376,9 +1372,8 @@ bool APIConnection::send_hello_response(const HelloRequest &msg) {
   HelloResponse resp;
   resp.api_version_major = 1;
   resp.api_version_minor = 12;
-  // Temporary string for concatenation - will be valid during send_message call
+  // Send only the version string - the client only logs this for debugging and doesn't use it otherwise
-  std::string server_info = App.get_name() + " (esphome v" ESPHOME_VERSION ")";
+  resp.set_server_info(ESPHOME_VERSION_REF);
-  resp.set_server_info(StringRef(server_info));
   resp.set_name(StringRef(App.get_name()));
 
 #ifdef USE_API_PASSWORD
@@ -1425,8 +1420,6 @@ bool APIConnection::send_device_info_response(const DeviceInfoRequest &msg) {
   std::string mac_address = get_mac_address_pretty();
   resp.set_mac_address(StringRef(mac_address));
 
-  // Compile-time StringRef constants
-  static constexpr auto ESPHOME_VERSION_REF = StringRef::from_lit(ESPHOME_VERSION);
   resp.set_esphome_version(ESPHOME_VERSION_REF);
 
   resp.set_compilation_time(App.get_compilation_time_ref());

esphome/components/api/api_connection.h

@@ -219,7 +219,6 @@ class APIConnection final : public APIServerConnection {
 #ifdef USE_API_HOMEASSISTANT_STATES
   void subscribe_home_assistant_states(const SubscribeHomeAssistantStatesRequest &msg) override;
 #endif
-  bool send_get_time_response(const GetTimeRequest &msg) override;
 #ifdef USE_API_SERVICES
   void execute_service(const ExecuteServiceRequest &msg) override;
 #endif

esphome/components/api/api_pb2.cpp

@@ -921,14 +921,6 @@ bool GetTimeResponse::decode_32bit(uint32_t field_id, Proto32Bit value) {
   }
   return true;
 }
-void GetTimeResponse::encode(ProtoWriteBuffer buffer) const {
-  buffer.encode_fixed32(1, this->epoch_seconds);
-  buffer.encode_string(2, this->timezone_ref_);
-}
-void GetTimeResponse::calculate_size(ProtoSize &size) const {
-  size.add_fixed32(1, this->epoch_seconds);
-  size.add_length(1, this->timezone_ref_.size());
-}
 #ifdef USE_API_SERVICES
 void ListEntitiesServicesArgument::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_string(1, this->name_ref_);

esphome/components/api/api_pb2.h

@@ -1180,10 +1180,6 @@ class GetTimeResponse final : public ProtoDecodableMessage {
 #endif
   uint32_t epoch_seconds{0};
   std::string timezone{};
-  StringRef timezone_ref_{};
-  void set_timezone(const StringRef &ref) { this->timezone_ref_ = ref; }
-  void encode(ProtoWriteBuffer buffer) const override;
-  void calculate_size(ProtoSize &size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif

esphome/components/api/api_pb2_dump.cpp

@@ -1113,13 +1113,7 @@ void GetTimeRequest::dump_to(std::string &out) const { out.append("GetTimeReques
 void GetTimeResponse::dump_to(std::string &out) const {
   MessageDumpHelper helper(out, "GetTimeResponse");
   dump_field(out, "epoch_seconds", this->epoch_seconds);
-  out.append("  timezone: ");
+  dump_field(out, "timezone", this->timezone);
-  if (!this->timezone_ref_.empty()) {
-    out.append("'").append(this->timezone_ref_.c_str()).append("'");
-  } else {
-    out.append("'").append(this->timezone).append("'");
-  }
-  out.append("\n");
 }
 #ifdef USE_API_SERVICES
 void ListEntitiesServicesArgument::dump_to(std::string &out) const {

esphome/components/api/api_pb2_service.cpp

@@ -160,15 +160,6 @@ void APIServerConnectionBase::read_message(uint32_t msg_size, uint32_t msg_type,
       break;
     }
 #endif
-    case GetTimeRequest::MESSAGE_TYPE: {
-      GetTimeRequest msg;
-      // Empty message: no decode needed
-#ifdef HAS_PROTO_MESSAGE_DUMP
-      ESP_LOGVV(TAG, "on_get_time_request: %s", msg.dump().c_str());
-#endif
-      this->on_get_time_request(msg);
-      break;
-    }
     case GetTimeResponse::MESSAGE_TYPE: {
       GetTimeResponse msg;
       msg.decode(msg_data, msg_size);
@@ -656,11 +647,6 @@ void APIServerConnection::on_subscribe_home_assistant_states_request(const Subsc
   }
 }
 #endif
-void APIServerConnection::on_get_time_request(const GetTimeRequest &msg) {
-  if (this->check_connection_setup_() && !this->send_get_time_response(msg)) {
-    this->on_fatal_error();
-  }
-}
 #ifdef USE_API_SERVICES
 void APIServerConnection::on_execute_service_request(const ExecuteServiceRequest &msg) {
   if (this->check_authenticated_()) {

esphome/components/api/api_pb2_service.h

@@ -71,7 +71,7 @@ class APIServerConnectionBase : public ProtoService {
 #ifdef USE_API_HOMEASSISTANT_STATES
   virtual void on_home_assistant_state_response(const HomeAssistantStateResponse &value){};
 #endif
-  virtual void on_get_time_request(const GetTimeRequest &value){};
+
   virtual void on_get_time_response(const GetTimeResponse &value){};
 
 #ifdef USE_API_SERVICES
@@ -226,7 +226,6 @@ class APIServerConnection : public APIServerConnectionBase {
 #ifdef USE_API_HOMEASSISTANT_STATES
   virtual void subscribe_home_assistant_states(const SubscribeHomeAssistantStatesRequest &msg) = 0;
 #endif
-  virtual bool send_get_time_response(const GetTimeRequest &msg) = 0;
 #ifdef USE_API_SERVICES
   virtual void execute_service(const ExecuteServiceRequest &msg) = 0;
 #endif
@@ -348,7 +347,6 @@ class APIServerConnection : public APIServerConnectionBase {
 #ifdef USE_API_HOMEASSISTANT_STATES
   void on_subscribe_home_assistant_states_request(const SubscribeHomeAssistantStatesRequest &msg) override;
 #endif
-  void on_get_time_request(const GetTimeRequest &msg) override;
 #ifdef USE_API_SERVICES
   void on_execute_service_request(const ExecuteServiceRequest &msg) override;
 #endif

esphome/components/ethernet/ethernet_component.cpp

@@ -300,6 +300,7 @@ void EthernetComponent::loop() {
         this->state_ = EthernetComponentState::CONNECTING;
         this->start_connect_();
       } else {
+        this->finish_connect_();
         // When connected and stable, disable the loop to save CPU cycles
         this->disable_loop();
       }
@@ -486,10 +487,35 @@ void EthernetComponent::got_ip6_event_handler(void *arg, esp_event_base_t event_
 }
 #endif /* USE_NETWORK_IPV6 */
 
+void EthernetComponent::finish_connect_() {
+#if USE_NETWORK_IPV6
+  // Retry IPv6 link-local setup if it failed during initial connect
+  // This handles the case where min_ipv6_addr_count is NOT set (or is 0),
+  // allowing us to reach CONNECTED state with just IPv4.
+  // If IPv6 setup failed in start_connect_() because the interface wasn't ready:
+  // - Bootup timing issues (#10281)
+  // - Cable unplugged/network interruption (#10705)
+  // We can now retry since we're in CONNECTED state and the interface is definitely up.
+  if (!this->ipv6_setup_done_) {
+    esp_err_t err = esp_netif_create_ip6_linklocal(this->eth_netif_);
+    if (err == ESP_OK) {
+      ESP_LOGD(TAG, "IPv6 link-local address created (retry succeeded)");
+    }
+    // Always set the flag to prevent continuous retries
+    // If IPv6 setup fails here with the interface up and stable, it's
+    // likely a persistent issue (IPv6 disabled at router, hardware
+    // limitation, etc.) that won't be resolved by further retries.
+    // The device continues to work with IPv4.
+    this->ipv6_setup_done_ = true;
+  }
+#endif /* USE_NETWORK_IPV6 */
+}
+
 void EthernetComponent::start_connect_() {
   global_eth_component->got_ipv4_address_ = false;
 #if USE_NETWORK_IPV6
   global_eth_component->ipv6_count_ = 0;
+  this->ipv6_setup_done_ = false;
 #endif /* USE_NETWORK_IPV6 */
   this->connect_begin_ = millis();
   this->status_set_warning(LOG_STR("waiting for IP configuration"));
@@ -545,9 +571,27 @@ void EthernetComponent::start_connect_() {
     }
   }
 #if USE_NETWORK_IPV6
+  // Attempt to create IPv6 link-local address
+  // We MUST attempt this here, not just in finish_connect_(), because with
+  // min_ipv6_addr_count set, the component won't reach CONNECTED state without IPv6.
+  // However, this may fail with ESP_FAIL if the interface is not up yet:
+  // - At bootup when link isn't ready (#10281)
+  // - After disconnection/cable unplugged (#10705)
+  // We'll retry in finish_connect_() if it fails here.
   err = esp_netif_create_ip6_linklocal(this->eth_netif_);
   if (err != ESP_OK) {
-    ESPHL_ERROR_CHECK(err, "Enable IPv6 link local failed");
+    if (err == ESP_ERR_ESP_NETIF_INVALID_PARAMS) {
+      // This is a programming error, not a transient failure
+      ESPHL_ERROR_CHECK(err, "esp_netif_create_ip6_linklocal invalid parameters");
+    } else {
+      // ESP_FAIL means the interface isn't up yet
+      // This is expected and non-fatal, happens in multiple scenarios:
+      // - During reconnection after network interruptions (#10705)
+      // - At bootup when the link isn't ready yet (#10281)
+      // We'll retry once we reach CONNECTED state and the interface is up
+      ESP_LOGW(TAG, "esp_netif_create_ip6_linklocal failed: %s", esp_err_to_name(err));
+      // Don't mark component as failed - this is a transient error
+    }
   }
 #endif /* USE_NETWORK_IPV6 */
 
@@ -638,7 +682,9 @@ void EthernetComponent::get_eth_mac_address_raw(uint8_t *mac) {
 std::string EthernetComponent::get_eth_mac_address_pretty() {
   uint8_t mac[6];
   get_eth_mac_address_raw(mac);
-  return str_snprintf("%02X:%02X:%02X:%02X:%02X:%02X", 17, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+  char buf[18];
+  format_mac_addr_upper(mac, buf);
+  return std::string(buf);
 }
 
 eth_duplex_t EthernetComponent::get_duplex_mode() {

esphome/components/ethernet/ethernet_component.h

@@ -102,6 +102,7 @@ class EthernetComponent : public Component {
 #endif /* LWIP_IPV6 */
 
   void start_connect_();
+  void finish_connect_();
   void dump_connect_params_();
   /// @brief Set `RMII Reference Clock Select` bit for KSZ8081.
   void ksz8081_set_clock_reference_(esp_eth_mac_t *mac);
@@ -144,6 +145,7 @@ class EthernetComponent : public Component {
   bool got_ipv4_address_{false};
 #if LWIP_IPV6
   uint8_t ipv6_count_{0};
+  bool ipv6_setup_done_{false};
 #endif /* LWIP_IPV6 */
 
   // Pointers at the end (naturally aligned)

esphome/components/ina2xx_base/__init__.py

@@ -18,6 +18,7 @@ from esphome.const import (
     DEVICE_CLASS_TEMPERATURE,
     DEVICE_CLASS_VOLTAGE,
     STATE_CLASS_MEASUREMENT,
+    STATE_CLASS_TOTAL_INCREASING,
     UNIT_AMPERE,
     UNIT_CELSIUS,
     UNIT_VOLT,
@@ -162,7 +163,7 @@ INA2XX_SCHEMA = cv.Schema(
                 unit_of_measurement=UNIT_WATT_HOURS,
                 accuracy_decimals=8,
                 device_class=DEVICE_CLASS_ENERGY,
-                state_class=STATE_CLASS_MEASUREMENT,
+                state_class=STATE_CLASS_TOTAL_INCREASING,
             ),
             key=CONF_NAME,
         ),
@@ -170,7 +171,8 @@ INA2XX_SCHEMA = cv.Schema(
             sensor.sensor_schema(
                 unit_of_measurement=UNIT_JOULE,
                 accuracy_decimals=8,
-                state_class=STATE_CLASS_MEASUREMENT,
+                device_class=DEVICE_CLASS_ENERGY,
+                state_class=STATE_CLASS_TOTAL_INCREASING,
             ),
             key=CONF_NAME,
         ),

esphome/components/md5/md5.cpp

@@ -1,4 +1,3 @@
-#include <cstdio>
 #include <cstring>
 #include "md5.h"
 #ifdef USE_MD5
@@ -44,7 +43,9 @@ void MD5Digest::get_bytes(uint8_t *output) { memcpy(output, this->digest_, 16);
 
 void MD5Digest::get_hex(char *output) {
   for (size_t i = 0; i < 16; i++) {
-    sprintf(output + i * 2, "%02x", this->digest_[i]);
+    uint8_t byte = this->digest_[i];
+    output[i * 2] = format_hex_char(byte >> 4);
+    output[i * 2 + 1] = format_hex_char(byte & 0x0F);
   }
 }
 

esphome/components/wifi/wifi_component.cpp

@@ -593,7 +593,7 @@ void WiFiComponent::check_scanning_finished() {
   for (auto &res : this->scan_result_) {
     char bssid_s[18];
     auto bssid = res.get_bssid();
-    sprintf(bssid_s, "%02X:%02X:%02X:%02X:%02X:%02X", bssid[0], bssid[1], bssid[2], bssid[3], bssid[4], bssid[5]);
+    format_mac_addr_upper(bssid.data(), bssid_s);
 
     if (res.get_matches()) {
       ESP_LOGI(TAG, "- '%s' %s" LOG_SECRET("(%s) ") "%s", res.get_ssid().c_str(),

esphome/components/wifi_info/wifi_info_text_sensor.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "esphome/core/component.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/text_sensor/text_sensor.h"
 #include "esphome/components/wifi/wifi_component.h"
 #ifdef USE_WIFI
@@ -106,8 +107,8 @@ class BSSIDWiFiInfo : public PollingComponent, public text_sensor::TextSensor {
     wifi::bssid_t bssid = wifi::global_wifi_component->wifi_bssid();
     if (memcmp(bssid.data(), last_bssid_.data(), 6) != 0) {
       std::copy(bssid.begin(), bssid.end(), last_bssid_.begin());
-      char buf[30];
+      char buf[18];
-      sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X", bssid[0], bssid[1], bssid[2], bssid[3], bssid[4], bssid[5]);
+      format_mac_addr_upper(bssid.data(), buf);
       this->publish_state(buf);
     }
   }

esphome/core/helpers.cpp

@@ -255,23 +255,22 @@ size_t parse_hex(const char *str, size_t length, uint8_t *data, size_t count) {
 }
 
 std::string format_mac_address_pretty(const uint8_t *mac) {
-  return str_snprintf("%02X:%02X:%02X:%02X:%02X:%02X", 17, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+  char buf[18];
+  format_mac_addr_upper(mac, buf);
+  return std::string(buf);
 }
 
-static char format_hex_char(uint8_t v) { return v >= 10 ? 'a' + (v - 10) : '0' + v; }
 std::string format_hex(const uint8_t *data, size_t length) {
   std::string ret;
   ret.resize(length * 2);
   for (size_t i = 0; i < length; i++) {
-    ret[2 * i] = format_hex_char((data[i] & 0xF0) >> 4);
+    ret[2 * i] = format_hex_char(data[i] >> 4);
     ret[2 * i + 1] = format_hex_char(data[i] & 0x0F);
   }
   return ret;
 }
 std::string format_hex(const std::vector<uint8_t> &data) { return format_hex(data.data(), data.size()); }
 
-static char format_hex_pretty_char(uint8_t v) { return v >= 10 ? 'A' + (v - 10) : '0' + v; }
-
 // Shared implementation for uint8_t and string hex formatting
 static std::string format_hex_pretty_uint8(const uint8_t *data, size_t length, char separator, bool show_length) {
   if (data == nullptr || length == 0)
@@ -280,7 +279,7 @@ static std::string format_hex_pretty_uint8(const uint8_t *data, size_t length, c
   uint8_t multiple = separator ? 3 : 2;  // 3 if separator is not \0, 2 otherwise
   ret.resize(multiple * length - (separator ? 1 : 0));
   for (size_t i = 0; i < length; i++) {
-    ret[multiple * i] = format_hex_pretty_char((data[i] & 0xF0) >> 4);
+    ret[multiple * i] = format_hex_pretty_char(data[i] >> 4);
     ret[multiple * i + 1] = format_hex_pretty_char(data[i] & 0x0F);
     if (separator && i != length - 1)
       ret[multiple * i + 2] = separator;
@@ -591,7 +590,9 @@ bool HighFrequencyLoopRequester::is_high_frequency() { return num_requests > 0;
 std::string get_mac_address() {
   uint8_t mac[6];
   get_mac_address_raw(mac);
-  return str_snprintf("%02x%02x%02x%02x%02x%02x", 12, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+  char buf[13];
+  format_mac_addr_lower_no_sep(mac, buf);
+  return std::string(buf);
 }
 
 std::string get_mac_address_pretty() {

esphome/core/helpers.h

@@ -380,6 +380,35 @@ template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0> optional<
   return parse_hex<T>(str.c_str(), str.length());
 }
 
+/// Convert a nibble (0-15) to lowercase hex char
+inline char format_hex_char(uint8_t v) { return v >= 10 ? 'a' + (v - 10) : '0' + v; }
+
+/// Convert a nibble (0-15) to uppercase hex char (used for pretty printing)
+/// This always uses uppercase (A-F) for pretty/human-readable output
+inline char format_hex_pretty_char(uint8_t v) { return v >= 10 ? 'A' + (v - 10) : '0' + v; }
+
+/// Format MAC address as XX:XX:XX:XX:XX:XX (uppercase)
+inline void format_mac_addr_upper(const uint8_t *mac, char *output) {
+  for (size_t i = 0; i < 6; i++) {
+    uint8_t byte = mac[i];
+    output[i * 3] = format_hex_pretty_char(byte >> 4);
+    output[i * 3 + 1] = format_hex_pretty_char(byte & 0x0F);
+    if (i < 5)
+      output[i * 3 + 2] = ':';
+  }
+  output[17] = '\0';
+}
+
+/// Format MAC address as xxxxxxxxxxxxxx (lowercase, no separators)
+inline void format_mac_addr_lower_no_sep(const uint8_t *mac, char *output) {
+  for (size_t i = 0; i < 6; i++) {
+    uint8_t byte = mac[i];
+    output[i * 2] = format_hex_char(byte >> 4);
+    output[i * 2 + 1] = format_hex_char(byte & 0x0F);
+  }
+  output[12] = '\0';
+}
+
 /// Format the six-byte array \p mac into a MAC address.
 std::string format_mac_address_pretty(const uint8_t mac[6]);
 /// Format the byte array \p data of length \p len in lowercased hex.

esphome/core/scheduler.cpp

@@ -345,7 +345,7 @@ void HOT Scheduler::call(uint32_t now) {
     // Execute callback without holding lock to prevent deadlocks
     // if the callback tries to call defer() again
     if (!this->should_skip_item_(item.get())) {
-      this->execute_item_(item.get(), now);
+      now = this->execute_item_(item.get(), now);
     }
     // Recycle the defer item after execution
     this->recycle_item_(std::move(item));
@@ -483,7 +483,7 @@ void HOT Scheduler::call(uint32_t now) {
     // Warning: During callback(), a lot of stuff can happen, including:
     //  - timeouts/intervals get added, potentially invalidating vector pointers
     //  - timeouts/intervals get cancelled
-    this->execute_item_(item.get(), now);
+    now = this->execute_item_(item.get(), now);
 
     LockGuard guard{this->lock_};
 
@@ -568,11 +568,11 @@ void HOT Scheduler::pop_raw_() {
 }
 
 // Helper to execute a scheduler item
-void HOT Scheduler::execute_item_(SchedulerItem *item, uint32_t now) {
+uint32_t HOT Scheduler::execute_item_(SchedulerItem *item, uint32_t now) {
   App.set_current_component(item->component);
   WarnIfComponentBlockingGuard guard{item->component, now};
   item->callback();
-  guard.finish();
+  return guard.finish();
 }
 
 // Common implementation for cancel operations

esphome/core/scheduler.h

@@ -254,7 +254,7 @@ class Scheduler {
   }
 
   // Helper to execute a scheduler item
-  void execute_item_(SchedulerItem *item, uint32_t now);
+  uint32_t execute_item_(SchedulerItem *item, uint32_t now);
 
   // Helper to check if item should be skipped
   bool should_skip_item_(SchedulerItem *item) const {

requirements.txt

@@ -12,7 +12,7 @@ platformio==6.1.18  # When updating platformio, also update /docker/Dockerfile
 esptool==5.0.2
 click==8.1.7
 esphome-dashboard==20250904.0
-aioesphomeapi==40.1.0
+aioesphomeapi==40.2.1
 zeroconf==0.147.2
 puremagic==1.30
 ruamel.yaml==0.18.15 # dashboard_import

script/api_protobuf/api_protobuf.py

@@ -848,10 +848,17 @@ class FixedArrayBytesType(TypeInfo):
 
     @property
     def public_content(self) -> list[str]:
+        len_type = (
+            "uint8_t"
+            if self.array_size <= 255
+            else "uint16_t"
+            if self.array_size <= 65535
+            else "size_t"
+        )
         # Add both the array and length fields
         return [
             f"uint8_t {self.field_name}[{self.array_size}]{{}};",
-            f"uint8_t {self.field_name}_len{{0}};",
+            f"{len_type} {self.field_name}_len{{0}};",
         ]
 
     @property

tests/unit_tests/conftest.py

@@ -9,8 +9,10 @@ not be part of a unit test suite.
 
 """
 
+from collections.abc import Generator
 from pathlib import Path
 import sys
+from unittest.mock import Mock, patch
 
 import pytest
 
@@ -43,3 +45,45 @@ def setup_core(tmp_path: Path) -> Path:
     """Set up CORE with test paths."""
     CORE.config_path = str(tmp_path / "test.yaml")
     return tmp_path
+
+
+@pytest.fixture
+def mock_write_file_if_changed() -> Generator[Mock, None, None]:
+    """Mock write_file_if_changed for storage_json."""
+    with patch("esphome.storage_json.write_file_if_changed") as mock:
+        yield mock
+
+
+@pytest.fixture
+def mock_copy_file_if_changed() -> Generator[Mock, None, None]:
+    """Mock copy_file_if_changed for core.config."""
+    with patch("esphome.core.config.copy_file_if_changed") as mock:
+        yield mock
+
+
+@pytest.fixture
+def mock_run_platformio_cli() -> Generator[Mock, None, None]:
+    """Mock run_platformio_cli for platformio_api."""
+    with patch("esphome.platformio_api.run_platformio_cli") as mock:
+        yield mock
+
+
+@pytest.fixture
+def mock_run_platformio_cli_run() -> Generator[Mock, None, None]:
+    """Mock run_platformio_cli_run for platformio_api."""
+    with patch("esphome.platformio_api.run_platformio_cli_run") as mock:
+        yield mock
+
+
+@pytest.fixture
+def mock_decode_pc() -> Generator[Mock, None, None]:
+    """Mock _decode_pc for platformio_api."""
+    with patch("esphome.platformio_api._decode_pc") as mock:
+        yield mock
+
+
+@pytest.fixture
+def mock_run_external_command() -> Generator[Mock, None, None]:
+    """Mock run_external_command for platformio_api."""
+    with patch("esphome.platformio_api.run_external_command") as mock:
+        yield mock

tests/unit_tests/core/test_config.py

@@ -1,15 +1,34 @@
 """Unit tests for core config functionality including areas and devices."""
 
 from collections.abc import Callable
+import os
 from pathlib import Path
+import types
 from typing import Any
+from unittest.mock import MagicMock, Mock, patch
 
 import pytest
 
 from esphome import config_validation as cv, core
-from esphome.const import CONF_AREA, CONF_AREAS, CONF_DEVICES
+from esphome.const import (
-from esphome.core import config
+    CONF_AREA,
-from esphome.core.config import Area, validate_area_config
+    CONF_AREAS,
+    CONF_BUILD_PATH,
+    CONF_DEVICES,
+    CONF_ESPHOME,
+    CONF_NAME,
+    CONF_NAME_ADD_MAC_SUFFIX,
+    KEY_CORE,
+)
+from esphome.core import CORE, config
+from esphome.core.config import (
+    Area,
+    preload_core_config,
+    valid_include,
+    valid_project_name,
+    validate_area_config,
+    validate_hostname,
+)
 
 from .common import load_config_from_fixture
 
@@ -245,3 +264,307 @@ def test_add_platform_defines_priority() -> None:
         f"_add_platform_defines priority ({config._add_platform_defines.priority}) must be lower than "
         f"globals priority ({globals_to_code.priority}) to fix issue #10431 (sensor count bug with lambdas)"
     )
+
+
+def test_valid_include_with_angle_brackets() -> None:
+    """Test valid_include accepts angle bracket includes."""
+    assert valid_include("<ArduinoJson.h>") == "<ArduinoJson.h>"
+
+
+def test_valid_include_with_valid_file(tmp_path: Path) -> None:
+    """Test valid_include accepts valid include files."""
+    CORE.config_path = str(tmp_path / "test.yaml")
+    include_file = tmp_path / "include.h"
+    include_file.touch()
+
+    assert valid_include(str(include_file)) == str(include_file)
+
+
+def test_valid_include_with_valid_directory(tmp_path: Path) -> None:
+    """Test valid_include accepts valid directories."""
+    CORE.config_path = str(tmp_path / "test.yaml")
+    include_dir = tmp_path / "includes"
+    include_dir.mkdir()
+
+    assert valid_include(str(include_dir)) == str(include_dir)
+
+
+def test_valid_include_invalid_extension(tmp_path: Path) -> None:
+    """Test valid_include rejects files with invalid extensions."""
+    CORE.config_path = str(tmp_path / "test.yaml")
+    invalid_file = tmp_path / "file.txt"
+    invalid_file.touch()
+
+    with pytest.raises(cv.Invalid, match="Include has invalid file extension"):
+        valid_include(str(invalid_file))
+
+
+def test_valid_project_name_valid() -> None:
+    """Test valid_project_name accepts valid project names."""
+    assert valid_project_name("esphome.my_project") == "esphome.my_project"
+
+
+def test_valid_project_name_no_namespace() -> None:
+    """Test valid_project_name rejects names without namespace."""
+    with pytest.raises(cv.Invalid, match="project name needs to have a namespace"):
+        valid_project_name("my_project")
+
+
+def test_valid_project_name_multiple_dots() -> None:
+    """Test valid_project_name rejects names with multiple dots."""
+    with pytest.raises(cv.Invalid, match="project name needs to have a namespace"):
+        valid_project_name("esphome.my.project")
+
+
+def test_validate_hostname_valid() -> None:
+    """Test validate_hostname accepts valid hostnames."""
+    config = {CONF_NAME: "my-device", CONF_NAME_ADD_MAC_SUFFIX: False}
+    assert validate_hostname(config) == config
+
+
+def test_validate_hostname_too_long() -> None:
+    """Test validate_hostname rejects hostnames that are too long."""
+    config = {
+        CONF_NAME: "a" * 32,  # 32 chars, max is 31
+        CONF_NAME_ADD_MAC_SUFFIX: False,
+    }
+    with pytest.raises(cv.Invalid, match="Hostnames can only be 31 characters long"):
+        validate_hostname(config)
+
+
+def test_validate_hostname_too_long_with_mac_suffix() -> None:
+    """Test validate_hostname accounts for MAC suffix length."""
+    config = {
+        CONF_NAME: "a" * 25,  # 25 chars, max is 24 with MAC suffix
+        CONF_NAME_ADD_MAC_SUFFIX: True,
+    }
+    with pytest.raises(cv.Invalid, match="Hostnames can only be 24 characters long"):
+        validate_hostname(config)
+
+
+def test_validate_hostname_with_underscore(caplog) -> None:
+    """Test validate_hostname warns about underscores."""
+    config = {CONF_NAME: "my_device", CONF_NAME_ADD_MAC_SUFFIX: False}
+    assert validate_hostname(config) == config
+    assert (
+        "Using the '_' (underscore) character in the hostname is discouraged"
+        in caplog.text
+    )
+
+
+def test_preload_core_config_basic(setup_core: Path) -> None:
+    """Test preload_core_config sets basic CORE attributes."""
+    config = {
+        CONF_ESPHOME: {
+            CONF_NAME: "test_device",
+        },
+        "esp32": {},
+    }
+    result = {}
+
+    platform = preload_core_config(config, result)
+
+    assert CORE.name == "test_device"
+    assert platform == "esp32"
+    assert KEY_CORE in CORE.data
+    assert CONF_BUILD_PATH in config[CONF_ESPHOME]
+
+
+def test_preload_core_config_with_build_path(setup_core: Path) -> None:
+    """Test preload_core_config uses provided build path."""
+    config = {
+        CONF_ESPHOME: {
+            CONF_NAME: "test_device",
+            CONF_BUILD_PATH: "/custom/build/path",
+        },
+        "esp8266": {},
+    }
+    result = {}
+
+    platform = preload_core_config(config, result)
+
+    assert config[CONF_ESPHOME][CONF_BUILD_PATH] == "/custom/build/path"
+    assert platform == "esp8266"
+
+
+def test_preload_core_config_env_build_path(setup_core: Path) -> None:
+    """Test preload_core_config uses ESPHOME_BUILD_PATH env var."""
+    config = {
+        CONF_ESPHOME: {
+            CONF_NAME: "test_device",
+        },
+        "rp2040": {},
+    }
+    result = {}
+
+    with patch.dict(os.environ, {"ESPHOME_BUILD_PATH": "/env/build"}):
+        platform = preload_core_config(config, result)
+
+    assert CONF_BUILD_PATH in config[CONF_ESPHOME]
+    assert "test_device" in config[CONF_ESPHOME][CONF_BUILD_PATH]
+    assert platform == "rp2040"
+
+
+def test_preload_core_config_no_platform(setup_core: Path) -> None:
+    """Test preload_core_config raises when no platform is specified."""
+    config = {
+        CONF_ESPHOME: {
+            CONF_NAME: "test_device",
+        },
+    }
+    result = {}
+
+    # Mock _is_target_platform to avoid expensive component loading
+    with patch("esphome.core.config._is_target_platform") as mock_is_platform:
+        # Return True for known platforms
+        mock_is_platform.side_effect = lambda name: name in [
+            "esp32",
+            "esp8266",
+            "rp2040",
+        ]
+
+        with pytest.raises(cv.Invalid, match="Platform missing"):
+            preload_core_config(config, result)
+
+
+def test_preload_core_config_multiple_platforms(setup_core: Path) -> None:
+    """Test preload_core_config raises when multiple platforms are specified."""
+    config = {
+        CONF_ESPHOME: {
+            CONF_NAME: "test_device",
+        },
+        "esp32": {},
+        "esp8266": {},
+    }
+    result = {}
+
+    # Mock _is_target_platform to avoid expensive component loading
+    with patch("esphome.core.config._is_target_platform") as mock_is_platform:
+        # Return True for known platforms
+        mock_is_platform.side_effect = lambda name: name in [
+            "esp32",
+            "esp8266",
+            "rp2040",
+        ]
+
+        with pytest.raises(cv.Invalid, match="Found multiple target platform blocks"):
+            preload_core_config(config, result)
+
+
+def test_include_file_header(tmp_path: Path, mock_copy_file_if_changed: Mock) -> None:
+    """Test include_file adds include statement for header files."""
+    src_file = tmp_path / "source.h"
+    src_file.write_text("// Header content")
+
+    CORE.build_path = str(tmp_path / "build")
+
+    with patch("esphome.core.config.cg") as mock_cg:
+        # Mock RawStatement to capture the text
+        mock_raw_statement = MagicMock()
+        mock_raw_statement.text = ""
+
+        def raw_statement_side_effect(text):
+            mock_raw_statement.text = text
+            return mock_raw_statement
+
+        mock_cg.RawStatement.side_effect = raw_statement_side_effect
+
+        config.include_file(str(src_file), "test.h")
+
+        mock_copy_file_if_changed.assert_called_once()
+        mock_cg.add_global.assert_called_once()
+        # Check that include statement was added
+        assert '#include "test.h"' in mock_raw_statement.text
+
+
+def test_include_file_cpp(tmp_path: Path, mock_copy_file_if_changed: Mock) -> None:
+    """Test include_file does not add include for cpp files."""
+    src_file = tmp_path / "source.cpp"
+    src_file.write_text("// CPP content")
+
+    CORE.build_path = str(tmp_path / "build")
+
+    with patch("esphome.core.config.cg") as mock_cg:
+        config.include_file(str(src_file), "test.cpp")
+
+        mock_copy_file_if_changed.assert_called_once()
+        # Should not add include statement for .cpp files
+        mock_cg.add_global.assert_not_called()
+
+
+def test_get_usable_cpu_count() -> None:
+    """Test get_usable_cpu_count returns CPU count."""
+    count = config.get_usable_cpu_count()
+    assert isinstance(count, int)
+    assert count > 0
+
+
+def test_get_usable_cpu_count_with_process_cpu_count() -> None:
+    """Test get_usable_cpu_count uses process_cpu_count when available."""
+    # Test with process_cpu_count (Python 3.13+)
+    # Create a mock os module with process_cpu_count
+
+    mock_os = types.SimpleNamespace(process_cpu_count=lambda: 8, cpu_count=lambda: 4)
+
+    with patch("esphome.core.config.os", mock_os):
+        # When process_cpu_count exists, it should be used
+        count = config.get_usable_cpu_count()
+        assert count == 8
+
+    # Test fallback to cpu_count when process_cpu_count not available
+    mock_os_no_process = types.SimpleNamespace(cpu_count=lambda: 4)
+
+    with patch("esphome.core.config.os", mock_os_no_process):
+        count = config.get_usable_cpu_count()
+        assert count == 4
+
+
+def test_list_target_platforms(tmp_path: Path) -> None:
+    """Test _list_target_platforms returns available platforms."""
+    # Create mock components directory structure
+    components_dir = tmp_path / "components"
+    components_dir.mkdir()
+
+    # Create platform and non-platform directories with __init__.py
+    platforms = ["esp32", "esp8266", "rp2040", "libretiny", "host"]
+    non_platforms = ["sensor"]
+
+    for component in platforms + non_platforms:
+        component_dir = components_dir / component
+        component_dir.mkdir()
+        (component_dir / "__init__.py").touch()
+
+    # Create a file (not a directory)
+    (components_dir / "README.md").touch()
+
+    # Create a directory without __init__.py
+    (components_dir / "no_init").mkdir()
+
+    # Mock Path(__file__).parents[1] to return our tmp_path
+    with patch("esphome.core.config.Path") as mock_path:
+        mock_file_path = MagicMock()
+        mock_file_path.parents = [MagicMock(), tmp_path]
+        mock_path.return_value = mock_file_path
+
+        platforms = config._list_target_platforms()
+
+    assert isinstance(platforms, list)
+    # Should include platform components
+    assert "esp32" in platforms
+    assert "esp8266" in platforms
+    assert "rp2040" in platforms
+    assert "libretiny" in platforms
+    assert "host" in platforms
+    # Should not include non-platform components
+    assert "sensor" not in platforms
+    assert "README.md" not in platforms
+    assert "no_init" not in platforms
+
+
+def test_is_target_platform() -> None:
+    """Test _is_target_platform identifies valid platforms."""
+    assert config._is_target_platform("esp32") is True
+    assert config._is_target_platform("esp8266") is True
+    assert config._is_target_platform("rp2040") is True
+    assert config._is_target_platform("invalid_platform") is False
+    assert config._is_target_platform("api") is False  # Component but not platform

tests/unit_tests/test_platformio_api.py

@@ -1,10 +1,16 @@
 """Tests for platformio_api.py path functions."""
 
+import json
+import os
 from pathlib import Path
-from unittest.mock import patch
+import shutil
+from types import SimpleNamespace
+from unittest.mock import MagicMock, Mock, patch
+
+import pytest
 
 from esphome import platformio_api
-from esphome.core import CORE
+from esphome.core import CORE, EsphomeError
 
 
 def test_idedata_firmware_elf_path(setup_core: Path) -> None:
@@ -104,7 +110,9 @@ def test_flash_image_dataclass() -> None:
     assert image.offset == "0x10000"
 
 
-def test_load_idedata_returns_dict(setup_core: Path) -> None:
+def test_load_idedata_returns_dict(
+    setup_core: Path, mock_run_platformio_cli_run
+) -> None:
     """Test _load_idedata returns parsed idedata dict when successful."""
     CORE.build_path = str(setup_core / "build" / "test")
     CORE.name = "test"
@@ -118,12 +126,511 @@ def test_load_idedata_returns_dict(setup_core: Path) -> None:
     idedata_path.parent.mkdir(parents=True, exist_ok=True)
     idedata_path.write_text('{"prog_path": "/test/firmware.elf"}')
 
-    with patch("esphome.platformio_api.run_platformio_cli_run") as mock_run:
+    mock_run_platformio_cli_run.return_value = '{"prog_path": "/test/firmware.elf"}'
-        mock_run.return_value = '{"prog_path": "/test/firmware.elf"}'
 
-        config = {"name": "test"}
+    config = {"name": "test"}
-        result = platformio_api._load_idedata(config)
+    result = platformio_api._load_idedata(config)
 
     assert result is not None
     assert isinstance(result, dict)
     assert result["prog_path"] == "/test/firmware.elf"
+
+
+def test_load_idedata_uses_cache_when_valid(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _load_idedata uses cached data when unchanged."""
+    CORE.build_path = str(setup_core / "build" / "test")
+    CORE.name = "test"
+
+    # Create platformio.ini
+    platformio_ini = setup_core / "build" / "test" / "platformio.ini"
+    platformio_ini.parent.mkdir(parents=True, exist_ok=True)
+    platformio_ini.write_text("content")
+
+    # Create idedata cache file that's newer
+    idedata_path = setup_core / ".esphome" / "idedata" / "test.json"
+    idedata_path.parent.mkdir(parents=True, exist_ok=True)
+    idedata_path.write_text('{"prog_path": "/cached/firmware.elf"}')
+
+    # Make idedata newer than platformio.ini
+    platformio_ini_mtime = platformio_ini.stat().st_mtime
+    os.utime(idedata_path, (platformio_ini_mtime + 1, platformio_ini_mtime + 1))
+
+    config = {"name": "test"}
+    result = platformio_api._load_idedata(config)
+
+    # Should not call _run_idedata since cache is valid
+    mock_run_platformio_cli_run.assert_not_called()
+
+    assert result["prog_path"] == "/cached/firmware.elf"
+
+
+def test_load_idedata_regenerates_when_platformio_ini_newer(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _load_idedata regenerates when platformio.ini is newer."""
+    CORE.build_path = str(setup_core / "build" / "test")
+    CORE.name = "test"
+
+    # Create idedata cache file first
+    idedata_path = setup_core / ".esphome" / "idedata" / "test.json"
+    idedata_path.parent.mkdir(parents=True, exist_ok=True)
+    idedata_path.write_text('{"prog_path": "/old/firmware.elf"}')
+
+    # Create platformio.ini that's newer
+    idedata_mtime = idedata_path.stat().st_mtime
+    platformio_ini = setup_core / "build" / "test" / "platformio.ini"
+    platformio_ini.parent.mkdir(parents=True, exist_ok=True)
+    platformio_ini.write_text("content")
+    # Make platformio.ini newer than idedata
+    os.utime(platformio_ini, (idedata_mtime + 1, idedata_mtime + 1))
+
+    # Mock platformio to return new data
+    new_data = {"prog_path": "/new/firmware.elf"}
+    mock_run_platformio_cli_run.return_value = json.dumps(new_data)
+
+    config = {"name": "test"}
+    result = platformio_api._load_idedata(config)
+
+    # Should call _run_idedata since platformio.ini is newer
+    mock_run_platformio_cli_run.assert_called_once()
+
+    assert result["prog_path"] == "/new/firmware.elf"
+
+
+def test_load_idedata_regenerates_on_corrupted_cache(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _load_idedata regenerates when cache file is corrupted."""
+    CORE.build_path = str(setup_core / "build" / "test")
+    CORE.name = "test"
+
+    # Create platformio.ini
+    platformio_ini = setup_core / "build" / "test" / "platformio.ini"
+    platformio_ini.parent.mkdir(parents=True, exist_ok=True)
+    platformio_ini.write_text("content")
+
+    # Create corrupted idedata cache file
+    idedata_path = setup_core / ".esphome" / "idedata" / "test.json"
+    idedata_path.parent.mkdir(parents=True, exist_ok=True)
+    idedata_path.write_text('{"prog_path": invalid json')
+
+    # Make idedata newer so it would be used if valid
+    platformio_ini_mtime = platformio_ini.stat().st_mtime
+    os.utime(idedata_path, (platformio_ini_mtime + 1, platformio_ini_mtime + 1))
+
+    # Mock platformio to return new data
+    new_data = {"prog_path": "/new/firmware.elf"}
+    mock_run_platformio_cli_run.return_value = json.dumps(new_data)
+
+    config = {"name": "test"}
+    result = platformio_api._load_idedata(config)
+
+    # Should call _run_idedata since cache is corrupted
+    mock_run_platformio_cli_run.assert_called_once()
+
+    assert result["prog_path"] == "/new/firmware.elf"
+
+
+def test_run_idedata_parses_json_from_output(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _run_idedata extracts JSON from platformio output."""
+    config = {"name": "test"}
+
+    expected_data = {
+        "prog_path": "/path/to/firmware.elf",
+        "cc_path": "/path/to/gcc",
+        "extra": {"flash_images": []},
+    }
+
+    # Simulate platformio output with JSON embedded
+    mock_run_platformio_cli_run.return_value = (
+        f"Some preamble\n{json.dumps(expected_data)}\nSome postamble"
+    )
+
+    result = platformio_api._run_idedata(config)
+
+    assert result == expected_data
+
+
+def test_run_idedata_raises_on_no_json(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _run_idedata raises EsphomeError when no JSON found."""
+    config = {"name": "test"}
+
+    mock_run_platformio_cli_run.return_value = "No JSON in this output"
+
+    with pytest.raises(EsphomeError):
+        platformio_api._run_idedata(config)
+
+
+def test_run_idedata_raises_on_invalid_json(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test _run_idedata raises on malformed JSON."""
+    config = {"name": "test"}
+    mock_run_platformio_cli_run.return_value = '{"invalid": json"}'
+
+    # The ValueError from json.loads is re-raised
+    with pytest.raises(ValueError):
+        platformio_api._run_idedata(config)
+
+
+def test_run_platformio_cli_sets_environment_variables(
+    setup_core: Path, mock_run_external_command: Mock
+) -> None:
+    """Test run_platformio_cli sets correct environment variables."""
+    CORE.build_path = str(setup_core / "build" / "test")
+
+    with patch.dict(os.environ, {}, clear=False):
+        mock_run_external_command.return_value = 0
+        platformio_api.run_platformio_cli("test", "arg")
+
+        # Check environment variables were set
+        assert os.environ["PLATFORMIO_FORCE_COLOR"] == "true"
+        assert (
+            setup_core / "build" / "test"
+            in Path(os.environ["PLATFORMIO_BUILD_DIR"]).parents
+            or Path(os.environ["PLATFORMIO_BUILD_DIR"]) == setup_core / "build" / "test"
+        )
+        assert "PLATFORMIO_LIBDEPS_DIR" in os.environ
+        assert "PYTHONWARNINGS" in os.environ
+
+        # Check command was called correctly
+        mock_run_external_command.assert_called_once()
+        args = mock_run_external_command.call_args[0]
+        assert "platformio" in args
+        assert "test" in args
+        assert "arg" in args
+
+
+def test_run_platformio_cli_run_builds_command(
+    setup_core: Path, mock_run_platformio_cli: Mock
+) -> None:
+    """Test run_platformio_cli_run builds correct command."""
+    CORE.build_path = str(setup_core / "build" / "test")
+    mock_run_platformio_cli.return_value = 0
+
+    config = {"name": "test"}
+    platformio_api.run_platformio_cli_run(config, True, "extra", "args")
+
+    mock_run_platformio_cli.assert_called_once_with(
+        "run", "-d", CORE.build_path, "-v", "extra", "args"
+    )
+
+
+def test_run_compile(setup_core: Path, mock_run_platformio_cli_run: Mock) -> None:
+    """Test run_compile with process limit."""
+    from esphome.const import CONF_COMPILE_PROCESS_LIMIT, CONF_ESPHOME
+
+    CORE.build_path = str(setup_core / "build" / "test")
+    config = {CONF_ESPHOME: {CONF_COMPILE_PROCESS_LIMIT: 4}}
+    mock_run_platformio_cli_run.return_value = 0
+
+    platformio_api.run_compile(config, verbose=True)
+
+    mock_run_platformio_cli_run.assert_called_once_with(config, True, "-j4")
+
+
+def test_get_idedata_caches_result(
+    setup_core: Path, mock_run_platformio_cli_run: Mock
+) -> None:
+    """Test get_idedata caches result in CORE.data."""
+    from esphome.const import KEY_CORE
+
+    CORE.build_path = str(setup_core / "build" / "test")
+    CORE.name = "test"
+    CORE.data[KEY_CORE] = {}
+
+    # Create platformio.ini to avoid regeneration
+    platformio_ini = setup_core / "build" / "test" / "platformio.ini"
+    platformio_ini.parent.mkdir(parents=True, exist_ok=True)
+    platformio_ini.write_text("content")
+
+    # Mock platformio to return data
+    idedata = {"prog_path": "/test/firmware.elf"}
+    mock_run_platformio_cli_run.return_value = json.dumps(idedata)
+
+    config = {"name": "test"}
+
+    # First call should load and cache
+    result1 = platformio_api.get_idedata(config)
+    mock_run_platformio_cli_run.assert_called_once()
+
+    # Second call should use cache from CORE.data
+    result2 = platformio_api.get_idedata(config)
+    mock_run_platformio_cli_run.assert_called_once()  # Still only called once
+
+    assert result1 is result2
+    assert isinstance(result1, platformio_api.IDEData)
+    assert result1.firmware_elf_path == "/test/firmware.elf"
+
+
+def test_idedata_addr2line_path_windows(setup_core: Path) -> None:
+    """Test IDEData.addr2line_path on Windows."""
+    raw_data = {"prog_path": "/path/to/firmware.elf", "cc_path": "C:\\tools\\gcc.exe"}
+    idedata = platformio_api.IDEData(raw_data)
+
+    result = idedata.addr2line_path
+    assert result == "C:\\tools\\addr2line.exe"
+
+
+def test_idedata_addr2line_path_unix(setup_core: Path) -> None:
+    """Test IDEData.addr2line_path on Unix."""
+    raw_data = {"prog_path": "/path/to/firmware.elf", "cc_path": "/usr/bin/gcc"}
+    idedata = platformio_api.IDEData(raw_data)
+
+    result = idedata.addr2line_path
+    assert result == "/usr/bin/addr2line"
+
+
+def test_patch_structhash(setup_core: Path) -> None:
+    """Test patch_structhash monkey patches platformio functions."""
+    # Create simple namespace objects to act as modules
+    mock_cli = SimpleNamespace()
+    mock_helpers = SimpleNamespace()
+    mock_run = SimpleNamespace(cli=mock_cli, helpers=mock_helpers)
+
+    # Mock platformio modules
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio.run.cli": mock_cli,
+            "platformio.run.helpers": mock_helpers,
+            "platformio.run": mock_run,
+            "platformio.project.helpers": MagicMock(),
+            "platformio.fs": MagicMock(),
+            "platformio": MagicMock(),
+        },
+    ):
+        # Call patch_structhash
+        platformio_api.patch_structhash()
+
+        # Verify both modules had clean_build_dir patched
+        # Check that clean_build_dir was set on both modules
+        assert hasattr(mock_cli, "clean_build_dir")
+        assert hasattr(mock_helpers, "clean_build_dir")
+
+        # Verify they got the same function assigned
+        assert mock_cli.clean_build_dir is mock_helpers.clean_build_dir
+
+        # Verify it's a real function (not a Mock)
+        assert callable(mock_cli.clean_build_dir)
+        assert mock_cli.clean_build_dir.__name__ == "patched_clean_build_dir"
+
+
+def test_patched_clean_build_dir_removes_outdated(setup_core: Path) -> None:
+    """Test patched_clean_build_dir removes build dir when platformio.ini is newer."""
+    build_dir = setup_core / "build"
+    build_dir.mkdir()
+    platformio_ini = setup_core / "platformio.ini"
+    platformio_ini.write_text("config")
+
+    # Make platformio.ini newer than build_dir
+    build_mtime = build_dir.stat().st_mtime
+    os.utime(platformio_ini, (build_mtime + 1, build_mtime + 1))
+
+    # Track if directory was removed
+    removed_paths: list[str] = []
+
+    def track_rmtree(path: str) -> None:
+        removed_paths.append(path)
+        shutil.rmtree(path)
+
+    # Create mock modules that patch_structhash expects
+    mock_cli = SimpleNamespace()
+    mock_helpers = SimpleNamespace()
+    mock_project_helpers = MagicMock()
+    mock_project_helpers.get_project_dir.return_value = str(setup_core)
+    mock_fs = SimpleNamespace(rmtree=track_rmtree)
+
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio": SimpleNamespace(fs=mock_fs),
+            "platformio.fs": mock_fs,
+            "platformio.project.helpers": mock_project_helpers,
+            "platformio.run": SimpleNamespace(cli=mock_cli, helpers=mock_helpers),
+            "platformio.run.cli": mock_cli,
+            "platformio.run.helpers": mock_helpers,
+        },
+    ):
+        # Call patch_structhash to install the patched function
+        platformio_api.patch_structhash()
+
+        # Call the patched function
+        mock_helpers.clean_build_dir(str(build_dir), [])
+
+        # Verify directory was removed and recreated
+        assert len(removed_paths) == 1
+        assert removed_paths[0] == str(build_dir)
+        assert build_dir.exists()  # makedirs recreated it
+
+
+def test_patched_clean_build_dir_keeps_updated(setup_core: Path) -> None:
+    """Test patched_clean_build_dir keeps build dir when it's up to date."""
+    build_dir = setup_core / "build"
+    build_dir.mkdir()
+    test_file = build_dir / "test.txt"
+    test_file.write_text("test content")
+
+    platformio_ini = setup_core / "platformio.ini"
+    platformio_ini.write_text("config")
+
+    # Make build_dir newer than platformio.ini
+    ini_mtime = platformio_ini.stat().st_mtime
+    os.utime(build_dir, (ini_mtime + 1, ini_mtime + 1))
+
+    # Track if rmtree is called
+    removed_paths: list[str] = []
+
+    def track_rmtree(path: str) -> None:
+        removed_paths.append(path)
+
+    # Create mock modules
+    mock_cli = SimpleNamespace()
+    mock_helpers = SimpleNamespace()
+    mock_project_helpers = MagicMock()
+    mock_project_helpers.get_project_dir.return_value = str(setup_core)
+    mock_fs = SimpleNamespace(rmtree=track_rmtree)
+
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio": SimpleNamespace(fs=mock_fs),
+            "platformio.fs": mock_fs,
+            "platformio.project.helpers": mock_project_helpers,
+            "platformio.run": SimpleNamespace(cli=mock_cli, helpers=mock_helpers),
+            "platformio.run.cli": mock_cli,
+            "platformio.run.helpers": mock_helpers,
+        },
+    ):
+        # Call patch_structhash to install the patched function
+        platformio_api.patch_structhash()
+
+        # Call the patched function
+        mock_helpers.clean_build_dir(str(build_dir), [])
+
+        # Verify rmtree was NOT called
+        assert len(removed_paths) == 0
+
+        # Verify directory and file still exist
+        assert build_dir.exists()
+        assert test_file.exists()
+        assert test_file.read_text() == "test content"
+
+
+def test_patched_clean_build_dir_creates_missing(setup_core: Path) -> None:
+    """Test patched_clean_build_dir creates build dir when it doesn't exist."""
+    build_dir = setup_core / "build"
+    platformio_ini = setup_core / "platformio.ini"
+    platformio_ini.write_text("config")
+
+    # Ensure build_dir doesn't exist
+    assert not build_dir.exists()
+
+    # Track if rmtree is called
+    removed_paths: list[str] = []
+
+    def track_rmtree(path: str) -> None:
+        removed_paths.append(path)
+
+    # Create mock modules
+    mock_cli = SimpleNamespace()
+    mock_helpers = SimpleNamespace()
+    mock_project_helpers = MagicMock()
+    mock_project_helpers.get_project_dir.return_value = str(setup_core)
+    mock_fs = SimpleNamespace(rmtree=track_rmtree)
+
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio": SimpleNamespace(fs=mock_fs),
+            "platformio.fs": mock_fs,
+            "platformio.project.helpers": mock_project_helpers,
+            "platformio.run": SimpleNamespace(cli=mock_cli, helpers=mock_helpers),
+            "platformio.run.cli": mock_cli,
+            "platformio.run.helpers": mock_helpers,
+        },
+    ):
+        # Call patch_structhash to install the patched function
+        platformio_api.patch_structhash()
+
+        # Call the patched function
+        mock_helpers.clean_build_dir(str(build_dir), [])
+
+        # Verify rmtree was NOT called
+        assert len(removed_paths) == 0
+
+        # Verify directory was created
+        assert build_dir.exists()
+
+
+def test_process_stacktrace_esp8266_exception(setup_core: Path, caplog) -> None:
+    """Test process_stacktrace handles ESP8266 exceptions."""
+    config = {"name": "test"}
+
+    # Test exception type parsing
+    line = "Exception (28):"
+    backtrace_state = False
+
+    result = platformio_api.process_stacktrace(config, line, backtrace_state)
+
+    assert "Access to invalid address: LOAD (wild pointer?)" in caplog.text
+    assert result is False
+
+
+def test_process_stacktrace_esp8266_backtrace(
+    setup_core: Path, mock_decode_pc: Mock
+) -> None:
+    """Test process_stacktrace handles ESP8266 multi-line backtrace."""
+    config = {"name": "test"}
+
+    # Start of backtrace
+    line1 = ">>>stack>>>"
+    state = platformio_api.process_stacktrace(config, line1, False)
+    assert state is True
+
+    # Backtrace content with addresses
+    line2 = "40201234 40205678"
+    state = platformio_api.process_stacktrace(config, line2, state)
+    assert state is True
+    assert mock_decode_pc.call_count == 2
+
+    # End of backtrace
+    line3 = "<<<stack<<<"
+    state = platformio_api.process_stacktrace(config, line3, state)
+    assert state is False
+
+
+def test_process_stacktrace_esp32_backtrace(
+    setup_core: Path, mock_decode_pc: Mock
+) -> None:
+    """Test process_stacktrace handles ESP32 single-line backtrace."""
+    config = {"name": "test"}
+
+    line = "Backtrace: 0x40081234:0x3ffb1234 0x40085678:0x3ffb5678"
+    state = platformio_api.process_stacktrace(config, line, False)
+
+    # Should decode both addresses
+    assert mock_decode_pc.call_count == 2
+    mock_decode_pc.assert_any_call(config, "40081234")
+    mock_decode_pc.assert_any_call(config, "40085678")
+    assert state is False
+
+
+def test_process_stacktrace_bad_alloc(
+    setup_core: Path, mock_decode_pc: Mock, caplog
+) -> None:
+    """Test process_stacktrace handles bad alloc messages."""
+    config = {"name": "test"}
+
+    line = "last failed alloc call: 40201234(512)"
+    state = platformio_api.process_stacktrace(config, line, False)
+
+    assert "Memory allocation of 512 bytes failed at 40201234" in caplog.text
+    mock_decode_pc.assert_called_once_with(config, "40201234")
+    assert state is False

tests/unit_tests/test_storage_json.py

@@ -1,12 +1,15 @@
 """Tests for storage_json.py path functions."""
 
+from datetime import datetime
+import json
 from pathlib import Path
 import sys
-from unittest.mock import patch
+from unittest.mock import MagicMock, Mock, patch
 
 import pytest
 
 from esphome import storage_json
+from esphome.const import CONF_DISABLED, CONF_MDNS
 from esphome.core import CORE
 
 
@@ -115,7 +118,9 @@ def test_storage_json_firmware_bin_path_property(setup_core: Path) -> None:
     assert storage.firmware_bin_path == "/path/to/firmware.bin"
 
 
-def test_storage_json_save_creates_directory(setup_core: Path, tmp_path: Path) -> None:
+def test_storage_json_save_creates_directory(
+    setup_core: Path, tmp_path: Path, mock_write_file_if_changed: Mock
+) -> None:
     """Test StorageJSON.save creates storage directory if it doesn't exist."""
     storage_dir = tmp_path / "new_data" / "storage"
     storage_file = storage_dir / "test.json"
@@ -139,11 +144,10 @@ def test_storage_json_save_creates_directory(setup_core: Path, tmp_path: Path) -
         no_mdns=False,
     )
 
-    with patch("esphome.storage_json.write_file_if_changed") as mock_write:
+    storage.save(str(storage_file))
-        storage.save(str(storage_file))
+    mock_write_file_if_changed.assert_called_once()
-        mock_write.assert_called_once()
+    call_args = mock_write_file_if_changed.call_args[0]
-        call_args = mock_write.call_args[0]
+    assert call_args[0] == str(storage_file)
-        assert call_args[0] == str(storage_file)
 
 
 def test_storage_json_from_wizard(setup_core: Path) -> None:
@@ -180,3 +184,477 @@ def test_storage_paths_with_ha_addon(mock_is_ha_addon: bool, tmp_path: Path) ->
     result = storage_json.esphome_storage_path()
     expected = str(Path("/data") / "esphome.json")
     assert result == expected
+
+
+def test_storage_json_as_dict() -> None:
+    """Test StorageJSON.as_dict returns correct dictionary."""
+    storage = storage_json.StorageJSON(
+        storage_version=1,
+        name="test_device",
+        friendly_name="Test Device",
+        comment="Test comment",
+        esphome_version="2024.1.0",
+        src_version=1,
+        address="192.168.1.100",
+        web_port=80,
+        target_platform="ESP32",
+        build_path="/path/to/build",
+        firmware_bin_path="/path/to/firmware.bin",
+        loaded_integrations={"wifi", "api", "ota"},
+        loaded_platforms={"sensor", "binary_sensor"},
+        no_mdns=True,
+        framework="arduino",
+        core_platform="esp32",
+    )
+
+    result = storage.as_dict()
+
+    assert result["storage_version"] == 1
+    assert result["name"] == "test_device"
+    assert result["friendly_name"] == "Test Device"
+    assert result["comment"] == "Test comment"
+    assert result["esphome_version"] == "2024.1.0"
+    assert result["src_version"] == 1
+    assert result["address"] == "192.168.1.100"
+    assert result["web_port"] == 80
+    assert result["esp_platform"] == "ESP32"
+    assert result["build_path"] == "/path/to/build"
+    assert result["firmware_bin_path"] == "/path/to/firmware.bin"
+    assert "api" in result["loaded_integrations"]
+    assert "wifi" in result["loaded_integrations"]
+    assert "ota" in result["loaded_integrations"]
+    assert result["loaded_integrations"] == sorted(
+        ["wifi", "api", "ota"]
+    )  # Should be sorted
+    assert "sensor" in result["loaded_platforms"]
+    assert result["loaded_platforms"] == sorted(
+        ["sensor", "binary_sensor"]
+    )  # Should be sorted
+    assert result["no_mdns"] is True
+    assert result["framework"] == "arduino"
+    assert result["core_platform"] == "esp32"
+
+
+def test_storage_json_to_json() -> None:
+    """Test StorageJSON.to_json returns valid JSON string."""
+    storage = storage_json.StorageJSON(
+        storage_version=1,
+        name="test",
+        friendly_name="Test",
+        comment=None,
+        esphome_version="2024.1.0",
+        src_version=None,
+        address="test.local",
+        web_port=None,
+        target_platform="ESP8266",
+        build_path=None,
+        firmware_bin_path=None,
+        loaded_integrations=set(),
+        loaded_platforms=set(),
+        no_mdns=False,
+    )
+
+    json_str = storage.to_json()
+
+    # Should be valid JSON
+    parsed = json.loads(json_str)
+    assert parsed["name"] == "test"
+    assert parsed["storage_version"] == 1
+
+    # Should end with newline
+    assert json_str.endswith("\n")
+
+
+def test_storage_json_save(tmp_path: Path) -> None:
+    """Test StorageJSON.save writes file correctly."""
+    storage = storage_json.StorageJSON(
+        storage_version=1,
+        name="test",
+        friendly_name="Test",
+        comment=None,
+        esphome_version="2024.1.0",
+        src_version=None,
+        address="test.local",
+        web_port=None,
+        target_platform="ESP32",
+        build_path=None,
+        firmware_bin_path=None,
+        loaded_integrations=set(),
+        loaded_platforms=set(),
+        no_mdns=False,
+    )
+
+    save_path = tmp_path / "test.json"
+
+    with patch("esphome.storage_json.write_file_if_changed") as mock_write:
+        storage.save(str(save_path))
+        mock_write.assert_called_once_with(str(save_path), storage.to_json())
+
+
+def test_storage_json_from_esphome_core(setup_core: Path) -> None:
+    """Test StorageJSON.from_esphome_core creates correct storage object."""
+    # Mock CORE object
+    mock_core = MagicMock()
+    mock_core.name = "my_device"
+    mock_core.friendly_name = "My Device"
+    mock_core.comment = "A test device"
+    mock_core.address = "192.168.1.50"
+    mock_core.web_port = 8080
+    mock_core.target_platform = "esp32"
+    mock_core.is_esp32 = True
+    mock_core.build_path = "/build/my_device"
+    mock_core.firmware_bin = "/build/my_device/firmware.bin"
+    mock_core.loaded_integrations = {"wifi", "api"}
+    mock_core.loaded_platforms = {"sensor"}
+    mock_core.config = {CONF_MDNS: {CONF_DISABLED: True}}
+    mock_core.target_framework = "esp-idf"
+
+    with patch("esphome.components.esp32.get_esp32_variant") as mock_variant:
+        mock_variant.return_value = "ESP32-C3"
+
+        result = storage_json.StorageJSON.from_esphome_core(mock_core, old=None)
+
+    assert result.name == "my_device"
+    assert result.friendly_name == "My Device"
+    assert result.comment == "A test device"
+    assert result.address == "192.168.1.50"
+    assert result.web_port == 8080
+    assert result.target_platform == "ESP32-C3"
+    assert result.build_path == "/build/my_device"
+    assert result.firmware_bin_path == "/build/my_device/firmware.bin"
+    assert result.loaded_integrations == {"wifi", "api"}
+    assert result.loaded_platforms == {"sensor"}
+    assert result.no_mdns is True
+    assert result.framework == "esp-idf"
+    assert result.core_platform == "esp32"
+
+
+def test_storage_json_from_esphome_core_mdns_enabled(setup_core: Path) -> None:
+    """Test from_esphome_core with mDNS enabled."""
+    mock_core = MagicMock()
+    mock_core.name = "test"
+    mock_core.friendly_name = "Test"
+    mock_core.comment = None
+    mock_core.address = "test.local"
+    mock_core.web_port = None
+    mock_core.target_platform = "esp8266"
+    mock_core.is_esp32 = False
+    mock_core.build_path = "/build"
+    mock_core.firmware_bin = "/build/firmware.bin"
+    mock_core.loaded_integrations = set()
+    mock_core.loaded_platforms = set()
+    mock_core.config = {}  # No MDNS config means enabled
+    mock_core.target_framework = "arduino"
+
+    result = storage_json.StorageJSON.from_esphome_core(mock_core, old=None)
+
+    assert result.no_mdns is False
+
+
+def test_storage_json_load_valid_file(tmp_path: Path) -> None:
+    """Test StorageJSON.load with valid JSON file."""
+    storage_data = {
+        "storage_version": 1,
+        "name": "loaded_device",
+        "friendly_name": "Loaded Device",
+        "comment": "Loaded from file",
+        "esphome_version": "2024.1.0",
+        "src_version": 2,
+        "address": "10.0.0.1",
+        "web_port": 8080,
+        "esp_platform": "ESP32",
+        "build_path": "/loaded/build",
+        "firmware_bin_path": "/loaded/firmware.bin",
+        "loaded_integrations": ["wifi", "api"],
+        "loaded_platforms": ["sensor"],
+        "no_mdns": True,
+        "framework": "arduino",
+        "core_platform": "esp32",
+    }
+
+    file_path = tmp_path / "storage.json"
+    file_path.write_text(json.dumps(storage_data))
+
+    result = storage_json.StorageJSON.load(str(file_path))
+
+    assert result is not None
+    assert result.name == "loaded_device"
+    assert result.friendly_name == "Loaded Device"
+    assert result.comment == "Loaded from file"
+    assert result.esphome_version == "2024.1.0"
+    assert result.src_version == 2
+    assert result.address == "10.0.0.1"
+    assert result.web_port == 8080
+    assert result.target_platform == "ESP32"
+    assert result.build_path == "/loaded/build"
+    assert result.firmware_bin_path == "/loaded/firmware.bin"
+    assert result.loaded_integrations == {"wifi", "api"}
+    assert result.loaded_platforms == {"sensor"}
+    assert result.no_mdns is True
+    assert result.framework == "arduino"
+    assert result.core_platform == "esp32"
+
+
+def test_storage_json_load_invalid_file(tmp_path: Path) -> None:
+    """Test StorageJSON.load with invalid JSON file."""
+    file_path = tmp_path / "invalid.json"
+    file_path.write_text("not valid json{")
+
+    result = storage_json.StorageJSON.load(str(file_path))
+
+    assert result is None
+
+
+def test_storage_json_load_nonexistent_file() -> None:
+    """Test StorageJSON.load with non-existent file."""
+    result = storage_json.StorageJSON.load("/nonexistent/file.json")
+
+    assert result is None
+
+
+def test_storage_json_equality() -> None:
+    """Test StorageJSON equality comparison."""
+    storage1 = storage_json.StorageJSON(
+        storage_version=1,
+        name="test",
+        friendly_name="Test",
+        comment=None,
+        esphome_version="2024.1.0",
+        src_version=1,
+        address="test.local",
+        web_port=80,
+        target_platform="ESP32",
+        build_path="/build",
+        firmware_bin_path="/firmware.bin",
+        loaded_integrations={"wifi"},
+        loaded_platforms=set(),
+        no_mdns=False,
+    )
+
+    storage2 = storage_json.StorageJSON(
+        storage_version=1,
+        name="test",
+        friendly_name="Test",
+        comment=None,
+        esphome_version="2024.1.0",
+        src_version=1,
+        address="test.local",
+        web_port=80,
+        target_platform="ESP32",
+        build_path="/build",
+        firmware_bin_path="/firmware.bin",
+        loaded_integrations={"wifi"},
+        loaded_platforms=set(),
+        no_mdns=False,
+    )
+
+    storage3 = storage_json.StorageJSON(
+        storage_version=1,
+        name="different",  # Different name
+        friendly_name="Test",
+        comment=None,
+        esphome_version="2024.1.0",
+        src_version=1,
+        address="test.local",
+        web_port=80,
+        target_platform="ESP32",
+        build_path="/build",
+        firmware_bin_path="/firmware.bin",
+        loaded_integrations={"wifi"},
+        loaded_platforms=set(),
+        no_mdns=False,
+    )
+
+    assert storage1 == storage2
+    assert storage1 != storage3
+    assert storage1 != "not a storage object"
+
+
+def test_esphome_storage_json_as_dict() -> None:
+    """Test EsphomeStorageJSON.as_dict returns correct dictionary."""
+    storage = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret123",
+        last_update_check="2024-01-15T10:30:00",
+        remote_version="2024.1.1",
+    )
+
+    result = storage.as_dict()
+
+    assert result["storage_version"] == 1
+    assert result["cookie_secret"] == "secret123"
+    assert result["last_update_check"] == "2024-01-15T10:30:00"
+    assert result["remote_version"] == "2024.1.1"
+
+
+def test_esphome_storage_json_last_update_check_property() -> None:
+    """Test EsphomeStorageJSON.last_update_check property."""
+    storage = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret",
+        last_update_check="2024-01-15T10:30:00",
+        remote_version=None,
+    )
+
+    # Test getter
+    result = storage.last_update_check
+    assert isinstance(result, datetime)
+    assert result.year == 2024
+    assert result.month == 1
+    assert result.day == 15
+    assert result.hour == 10
+    assert result.minute == 30
+
+    # Test setter
+    new_date = datetime(2024, 2, 20, 15, 45, 30)
+    storage.last_update_check = new_date
+    assert storage.last_update_check_str == "2024-02-20T15:45:30"
+
+
+def test_esphome_storage_json_last_update_check_invalid() -> None:
+    """Test EsphomeStorageJSON.last_update_check with invalid date."""
+    storage = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret",
+        last_update_check="invalid date",
+        remote_version=None,
+    )
+
+    result = storage.last_update_check
+    assert result is None
+
+
+def test_esphome_storage_json_to_json() -> None:
+    """Test EsphomeStorageJSON.to_json returns valid JSON string."""
+    storage = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="mysecret",
+        last_update_check="2024-01-15T10:30:00",
+        remote_version="2024.1.1",
+    )
+
+    json_str = storage.to_json()
+
+    # Should be valid JSON
+    parsed = json.loads(json_str)
+    assert parsed["cookie_secret"] == "mysecret"
+    assert parsed["storage_version"] == 1
+
+    # Should end with newline
+    assert json_str.endswith("\n")
+
+
+def test_esphome_storage_json_save(tmp_path: Path) -> None:
+    """Test EsphomeStorageJSON.save writes file correctly."""
+    storage = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret",
+        last_update_check=None,
+        remote_version=None,
+    )
+
+    save_path = tmp_path / "esphome.json"
+
+    with patch("esphome.storage_json.write_file_if_changed") as mock_write:
+        storage.save(str(save_path))
+        mock_write.assert_called_once_with(str(save_path), storage.to_json())
+
+
+def test_esphome_storage_json_load_valid_file(tmp_path: Path) -> None:
+    """Test EsphomeStorageJSON.load with valid JSON file."""
+    storage_data = {
+        "storage_version": 1,
+        "cookie_secret": "loaded_secret",
+        "last_update_check": "2024-01-20T14:30:00",
+        "remote_version": "2024.1.2",
+    }
+
+    file_path = tmp_path / "esphome.json"
+    file_path.write_text(json.dumps(storage_data))
+
+    result = storage_json.EsphomeStorageJSON.load(str(file_path))
+
+    assert result is not None
+    assert result.storage_version == 1
+    assert result.cookie_secret == "loaded_secret"
+    assert result.last_update_check_str == "2024-01-20T14:30:00"
+    assert result.remote_version == "2024.1.2"
+
+
+def test_esphome_storage_json_load_invalid_file(tmp_path: Path) -> None:
+    """Test EsphomeStorageJSON.load with invalid JSON file."""
+    file_path = tmp_path / "invalid.json"
+    file_path.write_text("not valid json{")
+
+    result = storage_json.EsphomeStorageJSON.load(str(file_path))
+
+    assert result is None
+
+
+def test_esphome_storage_json_load_nonexistent_file() -> None:
+    """Test EsphomeStorageJSON.load with non-existent file."""
+    result = storage_json.EsphomeStorageJSON.load("/nonexistent/file.json")
+
+    assert result is None
+
+
+def test_esphome_storage_json_get_default() -> None:
+    """Test EsphomeStorageJSON.get_default creates default storage."""
+    with patch("esphome.storage_json.os.urandom") as mock_urandom:
+        # Mock urandom to return predictable bytes
+        mock_urandom.return_value = b"test" * 16  # 64 bytes
+
+        result = storage_json.EsphomeStorageJSON.get_default()
+
+    assert result.storage_version == 1
+    assert len(result.cookie_secret) == 128  # 64 bytes hex = 128 chars
+    assert result.last_update_check is None
+    assert result.remote_version is None
+
+
+def test_esphome_storage_json_equality() -> None:
+    """Test EsphomeStorageJSON equality comparison."""
+    storage1 = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret",
+        last_update_check="2024-01-15T10:30:00",
+        remote_version="2024.1.1",
+    )
+
+    storage2 = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="secret",
+        last_update_check="2024-01-15T10:30:00",
+        remote_version="2024.1.1",
+    )
+
+    storage3 = storage_json.EsphomeStorageJSON(
+        storage_version=1,
+        cookie_secret="different",  # Different secret
+        last_update_check="2024-01-15T10:30:00",
+        remote_version="2024.1.1",
+    )
+
+    assert storage1 == storage2
+    assert storage1 != storage3
+    assert storage1 != "not a storage object"
+
+
+def test_storage_json_load_legacy_esphomeyaml_version(tmp_path: Path) -> None:
+    """Test loading storage with legacy esphomeyaml_version field."""
+    storage_data = {
+        "storage_version": 1,
+        "name": "legacy_device",
+        "friendly_name": "Legacy Device",
+        "esphomeyaml_version": "1.14.0",  # Legacy field name
+        "address": "legacy.local",
+        "esp_platform": "ESP8266",
+    }
+
+    file_path = tmp_path / "legacy.json"
+    file_path.write_text(json.dumps(storage_data))
+
+    result = storage_json.StorageJSON.load(str(file_path))
+
+    assert result is not None
+    assert result.esphome_version == "1.14.0"  # Should map to esphome_version