Merge remote-tracking branch 'upstream/dev' into light-addr

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

.clang-tidy.hash

@@ -1 +1 @@
-d7693a1e996cacd4a3d1c9a16336799c2a8cc3db02e4e74084151ce964581248
+3d46b63015d761c85ca9cb77ab79a389509e5776701fb22aed16e7b79d432c0c

.github/workflows/auto-label-pr.yml

@@ -53,6 +53,7 @@ jobs:
               'new-target-platform',
               'merging-to-release',
               'merging-to-beta',
+              'chained-pr',
               'core',
               'small-pr',
               'dashboard',
@@ -140,6 +141,8 @@ jobs:
                 labels.add('merging-to-release');
               } else if (baseRef === 'beta') {
                 labels.add('merging-to-beta');
+              } else if (baseRef !== 'dev') {
+                labels.add('chained-pr');
               }
 
               return labels;
@@ -528,8 +531,8 @@ jobs:
             const apiData = await fetchApiData();
             const baseRef = context.payload.pull_request.base.ref;
 
-            // Early exit for non-dev branches
-            if (baseRef !== 'dev') {
+            // Early exit for release and beta branches only
+            if (baseRef === 'release' || baseRef === 'beta') {
               const branchLabels = await detectMergeBranch();
               const finalLabels = Array.from(branchLabels);
 

.github/workflows/ci.yml

@@ -178,6 +178,8 @@ jobs:
       component-test-count: ${{ steps.determine.outputs.component-test-count }}
       changed-cpp-file-count: ${{ steps.determine.outputs.changed-cpp-file-count }}
       memory_impact: ${{ steps.determine.outputs.memory-impact }}
+      cpp-unit-tests-run-all: ${{ steps.determine.outputs.cpp-unit-tests-run-all }}
+      cpp-unit-tests-components: ${{ steps.determine.outputs.cpp-unit-tests-components }}
     steps:
       - name: Check out code from GitHub
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
@@ -210,6 +212,8 @@ jobs:
           echo "component-test-count=$(echo "$output" | jq -r '.component_test_count')" >> $GITHUB_OUTPUT
           echo "changed-cpp-file-count=$(echo "$output" | jq -r '.changed_cpp_file_count')" >> $GITHUB_OUTPUT
           echo "memory-impact=$(echo "$output" | jq -c '.memory_impact')" >> $GITHUB_OUTPUT
+          echo "cpp-unit-tests-run-all=$(echo "$output" | jq -r '.cpp_unit_tests_run_all')" >> $GITHUB_OUTPUT
+          echo "cpp-unit-tests-components=$(echo "$output" | jq -c '.cpp_unit_tests_components')" >> $GITHUB_OUTPUT
 
   integration-tests:
     name: Run integration tests
@@ -247,6 +251,33 @@ jobs:
           . venv/bin/activate
           pytest -vv --no-cov --tb=native -n auto tests/integration/
 
+  cpp-unit-tests:
+    name: Run C++ unit tests
+    runs-on: ubuntu-24.04
+    needs:
+      - common
+      - determine-jobs
+    if: github.event_name == 'pull_request' && (needs.determine-jobs.outputs.cpp-unit-tests-run-all == 'true' || needs.determine-jobs.outputs.cpp-unit-tests-components != '[]')
+    steps:
+      - name: Check out code from GitHub
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+
+      - name: Restore Python
+        uses: ./.github/actions/restore-python
+        with:
+          python-version: ${{ env.DEFAULT_PYTHON }}
+          cache-key: ${{ needs.common.outputs.cache-key }}
+
+      - name: Run cpp_unit_test.py
+        run: |
+          . venv/bin/activate
+          if [ "${{ needs.determine-jobs.outputs.cpp-unit-tests-run-all }}" = "true" ]; then
+            script/cpp_unit_test.py --all
+          else
+            ARGS=$(echo '${{ needs.determine-jobs.outputs.cpp-unit-tests-components }}' | jq -r '.[] | @sh' | xargs)
+            script/cpp_unit_test.py $ARGS
+          fi
+
   clang-tidy-single:
     name: ${{ matrix.name }}
     runs-on: ubuntu-24.04

.github/workflows/status-check-labels.yml

@@ -14,6 +14,7 @@ jobs:
         label:
           - needs-docs
           - merge-after-release
+          - chained-pr
     steps:
       - name: Check for ${{ matrix.label }} label
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0

esphome/components/api/api_connection.cpp

@@ -1572,7 +1572,13 @@ bool APIConnection::send_noise_encryption_set_key_response(const NoiseEncryption
   resp.success = false;
 
   psk_t psk{};
-  if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
+  if (msg.key.empty()) {
+    if (this->parent_->clear_noise_psk(true)) {
+      resp.success = true;
+    } else {
+      ESP_LOGW(TAG, "Failed to clear encryption key");
+    }
+  } else if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
     ESP_LOGW(TAG, "Invalid encryption key length");
   } else if (!this->parent_->save_noise_psk(psk, true)) {
     ESP_LOGW(TAG, "Failed to save encryption key");

esphome/components/api/api_server.cpp

@@ -468,6 +468,31 @@ uint16_t APIServer::get_port() const { return this->port_; }
 void APIServer::set_reboot_timeout(uint32_t reboot_timeout) { this->reboot_timeout_ = reboot_timeout; }
 
 #ifdef USE_API_NOISE
+bool APIServer::update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg,
+                                  const LogString *fail_log_msg, const psk_t &active_psk, bool make_active) {
+  if (!this->noise_pref_.save(&new_psk)) {
+    ESP_LOGW(TAG, "%s", LOG_STR_ARG(fail_log_msg));
+    return false;
+  }
+  // ensure it's written immediately
+  if (!global_preferences->sync()) {
+    ESP_LOGW(TAG, "Failed to sync preferences");
+    return false;
+  }
+  ESP_LOGD(TAG, "%s", LOG_STR_ARG(save_log_msg));
+  if (make_active) {
+    this->set_timeout(100, [this, active_psk]() {
+      ESP_LOGW(TAG, "Disconnecting all clients to reset PSK");
+      this->set_noise_psk(active_psk);
+      for (auto &c : this->clients_) {
+        DisconnectRequest req;
+        c->send_message(req, DisconnectRequest::MESSAGE_TYPE);
+      }
+    });
+  }
+  return true;
+}
+
 bool APIServer::save_noise_psk(psk_t psk, bool make_active) {
 #ifdef USE_API_NOISE_PSK_FROM_YAML
   // When PSK is set from YAML, this function should never be called
@@ -482,27 +507,21 @@ bool APIServer::save_noise_psk(psk_t psk, bool make_active) {
   }
 
   SavedNoisePsk new_saved_psk{psk};
-  if (!this->noise_pref_.save(&new_saved_psk)) {
-    ESP_LOGW(TAG, "Failed to save Noise PSK");
-    return false;
-  }
-  // ensure it's written immediately
-  if (!global_preferences->sync()) {
-    ESP_LOGW(TAG, "Failed to sync preferences");
-    return false;
-  }
-  ESP_LOGD(TAG, "Noise PSK saved");
-  if (make_active) {
-    this->set_timeout(100, [this, psk]() {
-      ESP_LOGW(TAG, "Disconnecting all clients to reset PSK");
-      this->set_noise_psk(psk);
-      for (auto &c : this->clients_) {
-        DisconnectRequest req;
-        c->send_message(req, DisconnectRequest::MESSAGE_TYPE);
-      }
-    });
-  }
-  return true;
+  return this->update_noise_psk_(new_saved_psk, LOG_STR("Noise PSK saved"), LOG_STR("Failed to save Noise PSK"), psk,
+                                 make_active);
+#endif
+}
+bool APIServer::clear_noise_psk(bool make_active) {
+#ifdef USE_API_NOISE_PSK_FROM_YAML
+  // When PSK is set from YAML, this function should never be called
+  // but if it is, reject the change
+  ESP_LOGW(TAG, "Key set in YAML");
+  return false;
+#else
+  SavedNoisePsk empty_psk{};
+  psk_t empty{};
+  return this->update_noise_psk_(empty_psk, LOG_STR("Noise PSK cleared"), LOG_STR("Failed to clear Noise PSK"), empty,
+                                 make_active);
 #endif
 }
 #endif

esphome/components/api/api_server.h

@@ -53,6 +53,7 @@ class APIServer : public Component, public Controller {
 
 #ifdef USE_API_NOISE
   bool save_noise_psk(psk_t psk, bool make_active = true);
+  bool clear_noise_psk(bool make_active = true);
   void set_noise_psk(psk_t psk) { noise_ctx_->set_psk(psk); }
   std::shared_ptr<APINoiseContext> get_noise_ctx() { return noise_ctx_; }
 #endif  // USE_API_NOISE
@@ -174,6 +175,10 @@ class APIServer : public Component, public Controller {
 
  protected:
   void schedule_reboot_timeout_();
+#ifdef USE_API_NOISE
+  bool update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg, const LogString *fail_log_msg,
+                         const psk_t &active_psk, bool make_active);
+#endif  // USE_API_NOISE
   // Pointers and pointer-like types first (4 bytes each)
   std::unique_ptr<socket::Socket> socket_ = nullptr;
 #ifdef USE_API_CLIENT_CONNECTED_TRIGGER

esphome/components/binary_sensor/automation.h

@@ -2,11 +2,11 @@
 
 #include <cinttypes>
 #include <utility>
-#include <vector>
 
 #include "esphome/core/component.h"
 #include "esphome/core/automation.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/binary_sensor/binary_sensor.h"
 
 namespace esphome {
@@ -92,8 +92,8 @@ class DoubleClickTrigger : public Trigger<> {
 
 class MultiClickTrigger : public Trigger<>, public Component {
  public:
-  explicit MultiClickTrigger(BinarySensor *parent, std::vector<MultiClickTriggerEvent> timing)
-      : parent_(parent), timing_(std::move(timing)) {}
+  explicit MultiClickTrigger(BinarySensor *parent, std::initializer_list<MultiClickTriggerEvent> timing)
+      : parent_(parent), timing_(timing) {}
 
   void setup() override {
     this->last_state_ = this->parent_->get_state_default(false);
@@ -115,7 +115,7 @@ class MultiClickTrigger : public Trigger<>, public Component {
   void trigger_();
 
   BinarySensor *parent_;
-  std::vector<MultiClickTriggerEvent> timing_;
+  FixedVector<MultiClickTriggerEvent> timing_;
   uint32_t invalid_cooldown_{1000};
   optional<size_t> at_index_{};
   bool last_state_{false};

esphome/components/esp32/__init__.py

@@ -550,6 +550,32 @@ CONF_ENABLE_LWIP_BRIDGE_INTERFACE = "enable_lwip_bridge_interface"
 CONF_ENABLE_LWIP_TCPIP_CORE_LOCKING = "enable_lwip_tcpip_core_locking"
 CONF_ENABLE_LWIP_CHECK_THREAD_SAFETY = "enable_lwip_check_thread_safety"
 CONF_DISABLE_LIBC_LOCKS_IN_IRAM = "disable_libc_locks_in_iram"
+CONF_DISABLE_VFS_SUPPORT_TERMIOS = "disable_vfs_support_termios"
+CONF_DISABLE_VFS_SUPPORT_SELECT = "disable_vfs_support_select"
+CONF_DISABLE_VFS_SUPPORT_DIR = "disable_vfs_support_dir"
+
+# VFS requirement tracking
+# Components that need VFS features can call require_vfs_select() or require_vfs_dir()
+KEY_VFS_SELECT_REQUIRED = "vfs_select_required"
+KEY_VFS_DIR_REQUIRED = "vfs_dir_required"
+
+
+def require_vfs_select() -> None:
+    """Mark that VFS select support is required by a component.
+
+    Call this from components that use esp_vfs_eventfd or other VFS select features.
+    This prevents CONFIG_VFS_SUPPORT_SELECT from being disabled.
+    """
+    CORE.data[KEY_VFS_SELECT_REQUIRED] = True
+
+
+def require_vfs_dir() -> None:
+    """Mark that VFS directory support is required by a component.
+
+    Call this from components that use directory functions (opendir, readdir, mkdir, etc.).
+    This prevents CONFIG_VFS_SUPPORT_DIR from being disabled.
+    """
+    CORE.data[KEY_VFS_DIR_REQUIRED] = True
 
 
 def _validate_idf_component(config: ConfigType) -> ConfigType:
@@ -615,6 +641,13 @@ FRAMEWORK_SCHEMA = cv.All(
                     cv.Optional(
                         CONF_DISABLE_LIBC_LOCKS_IN_IRAM, default=True
                     ): cv.boolean,
+                    cv.Optional(
+                        CONF_DISABLE_VFS_SUPPORT_TERMIOS, default=True
+                    ): cv.boolean,
+                    cv.Optional(
+                        CONF_DISABLE_VFS_SUPPORT_SELECT, default=True
+                    ): cv.boolean,
+                    cv.Optional(CONF_DISABLE_VFS_SUPPORT_DIR, default=True): cv.boolean,
                     cv.Optional(CONF_EXECUTE_FROM_PSRAM): cv.boolean,
                 }
             ),
@@ -962,6 +995,43 @@ async def to_code(config):
     if advanced.get(CONF_DISABLE_LIBC_LOCKS_IN_IRAM, True):
         add_idf_sdkconfig_option("CONFIG_LIBC_LOCKS_PLACE_IN_IRAM", False)
 
+    # Disable VFS support for termios (terminal I/O functions)
+    # ESPHome doesn't use termios functions on ESP32 (only used in host UART driver).
+    # Saves approximately 1.8KB of flash when disabled (default).
+    add_idf_sdkconfig_option(
+        "CONFIG_VFS_SUPPORT_TERMIOS",
+        not advanced.get(CONF_DISABLE_VFS_SUPPORT_TERMIOS, True),
+    )
+
+    # Disable VFS support for select() with file descriptors
+    # ESPHome only uses select() with sockets via lwip_select(), which still works.
+    # VFS select is only needed for UART/eventfd file descriptors.
+    # Components that need it (e.g., openthread) call require_vfs_select().
+    # Saves approximately 2.7KB of flash when disabled (default).
+    if CORE.data.get(KEY_VFS_SELECT_REQUIRED, False):
+        # Component requires VFS select - force enable regardless of user setting
+        add_idf_sdkconfig_option("CONFIG_VFS_SUPPORT_SELECT", True)
+    else:
+        # No component needs it - allow user to control (default: disabled)
+        add_idf_sdkconfig_option(
+            "CONFIG_VFS_SUPPORT_SELECT",
+            not advanced.get(CONF_DISABLE_VFS_SUPPORT_SELECT, True),
+        )
+
+    # Disable VFS support for directory functions (opendir, readdir, mkdir, etc.)
+    # ESPHome doesn't use directory functions on ESP32.
+    # Components that need it (e.g., storage components) call require_vfs_dir().
+    # Saves approximately 0.5KB+ of flash when disabled (default).
+    if CORE.data.get(KEY_VFS_DIR_REQUIRED, False):
+        # Component requires VFS directory support - force enable regardless of user setting
+        add_idf_sdkconfig_option("CONFIG_VFS_SUPPORT_DIR", True)
+    else:
+        # No component needs it - allow user to control (default: disabled)
+        add_idf_sdkconfig_option(
+            "CONFIG_VFS_SUPPORT_DIR",
+            not advanced.get(CONF_DISABLE_VFS_SUPPORT_DIR, True),
+        )
+
     cg.add_platformio_option("board_build.partitions", "partitions.csv")
     if CONF_PARTITIONS in config:
         add_extra_build_file(

esphome/components/event/event.cpp

@@ -8,12 +8,19 @@ namespace event {
 static const char *const TAG = "event";
 
 void Event::trigger(const std::string &event_type) {
-  auto found = types_.find(event_type);
-  if (found == types_.end()) {
+  // Linear search - faster than std::set for small datasets (1-5 items typical)
+  const std::string *found = nullptr;
+  for (const auto &type : this->types_) {
+    if (type == event_type) {
+      found = &type;
+      break;
+    }
+  }
+  if (found == nullptr) {
     ESP_LOGE(TAG, "'%s': invalid event type for trigger(): %s", this->get_name().c_str(), event_type.c_str());
     return;
   }
-  last_event_type = &(*found);
+  last_event_type = found;
   ESP_LOGD(TAG, "'%s' Triggered event '%s'", this->get_name().c_str(), last_event_type->c_str());
   this->event_callback_.call(event_type);
 }

esphome/components/event/event.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <set>
 #include <string>
 
 #include "esphome/core/component.h"
@@ -26,13 +25,13 @@ class Event : public EntityBase, public EntityBase_DeviceClass {
   const std::string *last_event_type;
 
   void trigger(const std::string &event_type);
-  void set_event_types(const std::set<std::string> &event_types) { this->types_ = event_types; }
-  std::set<std::string> get_event_types() const { return this->types_; }
+  void set_event_types(const std::initializer_list<std::string> &event_types) { this->types_ = event_types; }
+  const FixedVector<std::string> &get_event_types() const { return this->types_; }
   void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
 
  protected:
   CallbackManager<void(const std::string &event_type)> event_callback_;
-  std::set<std::string> types_;
+  FixedVector<std::string> types_;
 };
 
 }  // namespace event

esphome/components/gpio/switch/gpio_switch.cpp

@@ -67,7 +67,7 @@ void GPIOSwitch::write_state(bool state) {
   this->pin_->digital_write(state);
   this->publish_state(state);
 }
-void GPIOSwitch::set_interlock(const std::vector<Switch *> &interlock) { this->interlock_ = interlock; }
+void GPIOSwitch::set_interlock(const std::initializer_list<Switch *> &interlock) { this->interlock_ = interlock; }
 
 }  // namespace gpio
 }  // namespace esphome

esphome/components/gpio/switch/gpio_switch.h

@@ -2,10 +2,9 @@
 
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/switch/switch.h"
 
-#include <vector>
-
 namespace esphome {
 namespace gpio {
 
@@ -19,14 +18,14 @@ class GPIOSwitch : public switch_::Switch, public Component {
 
   void setup() override;
   void dump_config() override;
-  void set_interlock(const std::vector<Switch *> &interlock);
+  void set_interlock(const std::initializer_list<Switch *> &interlock);
   void set_interlock_wait_time(uint32_t interlock_wait_time) { interlock_wait_time_ = interlock_wait_time; }
 
  protected:
   void write_state(bool state) override;
 
   GPIOPin *pin_;
-  std::vector<Switch *> interlock_;
+  FixedVector<Switch *> interlock_;
   uint32_t interlock_wait_time_{0};
 };
 

esphome/components/light/addressable_light.cpp

@@ -61,6 +61,10 @@ void AddressableLightTransformer::start() {
   this->target_color_ *= to_uint8_scale(end_values.get_brightness() * end_values.get_state());
 }
 
+inline constexpr uint8_t subtract_scaled_difference(uint8_t a, uint8_t b, int32_t scale) {
+  return uint8_t(int32_t(a) - (((int32_t(a) - int32_t(b)) * scale) / 256));
+}
+
 optional<LightColorValues> AddressableLightTransformer::apply() {
   float smoothed_progress = LightTransformer::smoothed_progress(this->get_progress_());
 
@@ -74,38 +78,37 @@ optional<LightColorValues> AddressableLightTransformer::apply() {
   // all LEDs, we use the current state of each LED as the start.
 
   // We can't use a direct lerp smoothing here though - that would require creating a copy of the original
-  // state of each LED at the start of the transition.
-  // Instead, we "fake" the look of the LERP by using an exponential average over time and using
-  // dynamically-calculated alpha values to match the look.
+  // state of each LED at the start of the transition. Instead, we "fake" the look of lerp by calculating
+  // the delta between the current state and the target state, assuming that the delta represents the rest
+  // of the transition that was to be applied as of the previous transition step, and scaling the delta for
+  // what should be left after the current transition step. In this manner, the delta decays to zero as the
+  // transition progresses.
+  //
+  // Here's an example of how the algorithm progresses in discrete steps:
+  //
+  // At time = 0.00, 0% complete, 100% remaining, 100% will remain after this step, so the scale is 100% / 100% = 100%.
+  // At time = 0.10, 0% complete, 100% remaining, 90% will remain after this step, so the scale is 90% / 100% = 90%.
+  // At time = 0.20, 10% complete, 90% remaining, 80% will remain after this step, so the scale is 80% / 90% = 88.9%.
+  // At time = 0.50, 20% complete, 80% remaining, 50% will remain after this step, so the scale is 50% / 80% = 62.5%.
+  // At time = 0.90, 50% complete, 50% remaining, 10% will remain after this step, so the scale is 10% / 50% = 20%.
+  // At time = 0.91, 90% complete, 10% remaining, 9% will remain after this step, so the scale is 9% / 10% = 90%.
+  // At time = 1.00, 91% complete, 9% remaining, 0% will remain after this step, so the scale is 0% / 9% = 0%.
+  //
+  // Because the color values are quantized to 8 bit resolution after each step, the transition may appear
+  // non-linear when applying small deltas.
 
-  float denom = (1.0f - smoothed_progress);
-  float alpha = denom == 0.0f ? 1.0f : (smoothed_progress - this->last_transition_progress_) / denom;
-
-  // We need to use a low-resolution alpha here which makes the transition set in only after ~half of the length
-  // We solve this by accumulating the fractional part of the alpha over time.
-  float alpha255 = alpha * 255.0f;
-  float alpha255int = floorf(alpha255);
-  float alpha255remainder = alpha255 - alpha255int;
-
-  this->accumulated_alpha_ += alpha255remainder;
-  float alpha_add = floorf(this->accumulated_alpha_);
-  this->accumulated_alpha_ -= alpha_add;
-
-  alpha255 += alpha_add;
-  alpha255 = clamp(alpha255, 0.0f, 255.0f);
-  auto alpha8 = static_cast<uint8_t>(alpha255);
-
-  if (alpha8 != 0) {
-    uint8_t inv_alpha8 = 255 - alpha8;
-    Color add = this->target_color_ * alpha8;
-
-    for (auto led : this->light_)
-      led.set(add + led.get() * inv_alpha8);
+  if (smoothed_progress > this->last_transition_progress_ && this->last_transition_progress_ < 1.f) {
+    int32_t scale = int32_t(256.f * std::max((1.f - smoothed_progress) / (1.f - this->last_transition_progress_), 0.f));
+    for (auto led : this->light_) {
+      led.set_rgbw(subtract_scaled_difference(this->target_color_.red, led.get_red(), scale),
+                   subtract_scaled_difference(this->target_color_.green, led.get_green(), scale),
+                   subtract_scaled_difference(this->target_color_.blue, led.get_blue(), scale),
+                   subtract_scaled_difference(this->target_color_.white, led.get_white(), scale));
+    }
+    this->last_transition_progress_ = smoothed_progress;
+    this->light_.schedule_show();
   }
 
-  this->last_transition_progress_ = smoothed_progress;
-  this->light_.schedule_show();
-
   return {};
 }
 

esphome/components/light/addressable_light.h

@@ -113,7 +113,6 @@ class AddressableLightTransformer : public LightTransformer {
  protected:
   AddressableLight &light_;
   float last_transition_progress_{0.0f};
-  float accumulated_alpha_{0.0f};
   Color target_color_{};
 };
 

esphome/components/light/addressable_light_effect.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <utility>
-#include <vector>
 
 #include "esphome/core/component.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/light/light_state.h"
 #include "esphome/components/light/addressable_light.h"
 
@@ -113,7 +113,7 @@ struct AddressableColorWipeEffectColor {
 class AddressableColorWipeEffect : public AddressableLightEffect {
  public:
   explicit AddressableColorWipeEffect(const std::string &name) : AddressableLightEffect(name) {}
-  void set_colors(const std::vector<AddressableColorWipeEffectColor> &colors) { this->colors_ = colors; }
+  void set_colors(const std::initializer_list<AddressableColorWipeEffectColor> &colors) { this->colors_ = colors; }
   void set_add_led_interval(uint32_t add_led_interval) { this->add_led_interval_ = add_led_interval; }
   void set_reverse(bool reverse) { this->reverse_ = reverse; }
   void apply(AddressableLight &it, const Color &current_color) override {
@@ -155,7 +155,7 @@ class AddressableColorWipeEffect : public AddressableLightEffect {
   }
 
  protected:
-  std::vector<AddressableColorWipeEffectColor> colors_;
+  FixedVector<AddressableColorWipeEffectColor> colors_;
   size_t at_color_{0};
   uint32_t last_add_{0};
   uint32_t add_led_interval_{};

esphome/components/light/base_light_effects.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <utility>
-#include <vector>
 
 #include "esphome/core/automation.h"
+#include "esphome/core/helpers.h"
 #include "light_effect.h"
 
 namespace esphome {
@@ -188,10 +188,10 @@ class StrobeLightEffect : public LightEffect {
     this->last_switch_ = now;
   }
 
-  void set_colors(const std::vector<StrobeLightEffectColor> &colors) { this->colors_ = colors; }
+  void set_colors(const std::initializer_list<StrobeLightEffectColor> &colors) { this->colors_ = colors; }
 
  protected:
-  std::vector<StrobeLightEffectColor> colors_;
+  FixedVector<StrobeLightEffectColor> colors_;
   uint32_t last_switch_{0};
   size_t at_color_{0};
 };

esphome/components/light/esp_color_correction.h

@@ -17,19 +17,19 @@ class ESPColorCorrection {
                  this->color_correct_blue(color.blue), this->color_correct_white(color.white));
   }
   inline uint8_t color_correct_red(uint8_t red) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(red, this->max_brightness_.red), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(red, this->max_brightness_.red, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_green(uint8_t green) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(green, this->max_brightness_.green), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(green, this->max_brightness_.green, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_blue(uint8_t blue) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(blue, this->max_brightness_.blue), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(blue, this->max_brightness_.blue, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_white(uint8_t white) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(white, this->max_brightness_.white), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(white, this->max_brightness_.white, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline Color color_uncorrect(Color color) const ESPHOME_ALWAYS_INLINE {

esphome/components/openthread/__init__.py

@@ -4,6 +4,7 @@ from esphome.components.esp32 import (
     VARIANT_ESP32H2,
     add_idf_sdkconfig_option,
     only_on_variant,
+    require_vfs_select,
 )
 from esphome.components.mdns import MDNSComponent, enable_mdns_storage
 import esphome.config_validation as cv
@@ -106,6 +107,14 @@ _CONNECTION_SCHEMA = cv.Schema(
     }
 )
 
+
+def _require_vfs_select(config):
+    """Register VFS select requirement during config validation."""
+    # OpenThread uses esp_vfs_eventfd which requires VFS select support
+    require_vfs_select()
+    return config
+
+
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -122,6 +131,7 @@ CONFIG_SCHEMA = cv.All(
     cv.has_exactly_one_key(CONF_NETWORK_KEY, CONF_TLV),
     cv.only_with_esp_idf,
     only_on_variant(supported=[VARIANT_ESP32C6, VARIANT_ESP32H2]),
+    _require_vfs_select,
 )
 
 

esphome/components/uart/uart_component_esp8266.cpp

@@ -56,6 +56,13 @@ uint32_t ESP8266UartComponent::get_config() {
 }
 
 void ESP8266UartComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   // Use Arduino HardwareSerial UARTs if all used pins match the ones
   // preconfigured by the platform. For example if RX disabled but TX pin
   // is 1 we still want to use Serial.

esphome/components/uart/uart_component_esp_idf.cpp

@@ -6,6 +6,9 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/gpio.h"
+#include "driver/gpio.h"
+#include "soc/gpio_num.h"
 
 #ifdef USE_LOGGER
 #include "esphome/components/logger/logger.h"
@@ -104,6 +107,13 @@ void IDFUARTComponent::load_settings(bool dump_config) {
     return;
   }
 
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   int8_t tx = this->tx_pin_ != nullptr ? this->tx_pin_->get_pin() : -1;
   int8_t rx = this->rx_pin_ != nullptr ? this->rx_pin_->get_pin() : -1;
   int8_t flow_control = this->flow_control_pin_ != nullptr ? this->flow_control_pin_->get_pin() : -1;

esphome/components/uart/uart_component_libretiny.cpp

@@ -46,6 +46,13 @@ uint16_t LibreTinyUARTComponent::get_config() {
 }
 
 void LibreTinyUARTComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   int8_t tx_pin = tx_pin_ == nullptr ? -1 : tx_pin_->get_pin();
   int8_t rx_pin = rx_pin_ == nullptr ? -1 : rx_pin_->get_pin();
   bool tx_inverted = tx_pin_ != nullptr && tx_pin_->is_inverted();

esphome/components/uart/uart_component_rp2040.cpp

@@ -52,6 +52,13 @@ uint16_t RP2040UartComponent::get_config() {
 }
 
 void RP2040UartComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   uint16_t config = get_config();
 
   constexpr uint32_t valid_tx_uart_0 = __bitset({0, 12, 16, 28});

esphome/components/wifi/__init__.py

@@ -378,14 +378,19 @@ async def to_code(config):
     # Track if any network uses Enterprise authentication
     has_eap = False
 
-    def add_sta(ap, network):
-        ip_config = network.get(CONF_MANUAL_IP, config.get(CONF_MANUAL_IP))
-        cg.add(var.add_sta(wifi_network(network, ap, ip_config)))
+    # Initialize FixedVector with the count of networks
+    networks = config.get(CONF_NETWORKS, [])
+    if networks:
+        cg.add(var.init_sta(len(networks)))
 
-    for network in config.get(CONF_NETWORKS, []):
-        if CONF_EAP in network:
-            has_eap = True
-        cg.with_local_variable(network[CONF_ID], WiFiAP(), add_sta, network)
+        def add_sta(ap: cg.MockObj, network: dict) -> None:
+            ip_config = network.get(CONF_MANUAL_IP, config.get(CONF_MANUAL_IP))
+            cg.add(var.add_sta(wifi_network(network, ap, ip_config)))
+
+        for network in networks:
+            if CONF_EAP in network:
+                has_eap = True
+            cg.with_local_variable(network[CONF_ID], WiFiAP(), add_sta, network)
 
     if CONF_AP in config:
         conf = config[CONF_AP]

esphome/components/wifi/wifi_component.cpp

@@ -330,9 +330,11 @@ float WiFiComponent::get_loop_priority() const {
   return 10.0f;  // before other loop components
 }
 
+void WiFiComponent::init_sta(size_t count) { this->sta_.init(count); }
 void WiFiComponent::add_sta(const WiFiAP &ap) { this->sta_.push_back(ap); }
 void WiFiComponent::set_sta(const WiFiAP &ap) {
   this->clear_sta();
+  this->init_sta(1);
   this->add_sta(ap);
 }
 void WiFiComponent::clear_sta() { this->sta_.clear(); }

esphome/components/wifi/wifi_component.h

@@ -219,6 +219,7 @@ class WiFiComponent : public Component {
 
   void set_sta(const WiFiAP &ap);
   WiFiAP get_sta() { return this->selected_ap_; }
+  void init_sta(size_t count);
   void add_sta(const WiFiAP &ap);
   void clear_sta();
 
@@ -393,7 +394,7 @@ class WiFiComponent : public Component {
 #endif
 
   std::string use_address_;
-  std::vector<WiFiAP> sta_;
+  FixedVector<WiFiAP> sta_;
   std::vector<WiFiSTAPriority> sta_priorities_;
   wifi_scan_vector_t<WiFiScanResult> scan_result_;
   WiFiAP selected_ap_;

esphome/core/color.h

@@ -14,6 +14,15 @@ inline static constexpr uint8_t esp_scale8(uint8_t i, uint8_t scale) {
   return (uint16_t(i) * (1 + uint16_t(scale))) / 256;
 }
 
+/// Scale an 8-bit value by two 8-bit scale factors with improved precision.
+/// This is more accurate than calling esp_scale8() twice because it delays
+/// truncation until after both multiplications, preserving intermediate precision.
+/// For example: esp_scale8_twice(value, max_brightness, local_brightness)
+/// gives better results than esp_scale8(esp_scale8(value, max_brightness), local_brightness)
+inline static constexpr uint8_t esp_scale8_twice(uint8_t i, uint8_t scale1, uint8_t scale2) {
+  return (uint32_t(i) * (1 + uint32_t(scale1)) * (1 + uint32_t(scale2))) >> 16;
+}
+
 struct Color {
   union {
     struct {

esphome/core/defines.h

@@ -243,8 +243,10 @@
 // Dummy firmware payload for shelly_dimmer
 #define USE_SHD_FIRMWARE_MAJOR_VERSION 56
 #define USE_SHD_FIRMWARE_MINOR_VERSION 5
+// clang-format off
 #define USE_SHD_FIRMWARE_DATA \
   {}
+// clang-format on
 
 #define USE_WEBSERVER
 #define USE_WEBSERVER_AUTH

esphome/core/helpers.h

@@ -194,12 +194,8 @@ template<typename T> class FixedVector {
     size_ = 0;
   }
 
- public:
-  FixedVector() = default;
-
-  /// Constructor from initializer list - allocates exact size needed
-  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
-  FixedVector(std::initializer_list<T> init_list) {
+  // Helper to assign from initializer list (shared by constructor and assignment operator)
+  void assign_from_initializer_list_(std::initializer_list<T> init_list) {
     init(init_list.size());
     size_t idx = 0;
     for (const auto &item : init_list) {
@@ -209,6 +205,13 @@ template<typename T> class FixedVector {
     size_ = init_list.size();
   }
 
+ public:
+  FixedVector() = default;
+
+  /// Constructor from initializer list - allocates exact size needed
+  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
+  FixedVector(std::initializer_list<T> init_list) { assign_from_initializer_list_(init_list); }
+
   ~FixedVector() { cleanup_(); }
 
   // Disable copy operations (avoid accidental expensive copies)
@@ -234,6 +237,15 @@ template<typename T> class FixedVector {
     return *this;
   }
 
+  /// Assignment from initializer list - avoids temporary and move overhead
+  /// This enables: FixedVector<int> v; v = {1, 2, 3};
+  FixedVector &operator=(std::initializer_list<T> init_list) {
+    cleanup_();
+    reset_();
+    assign_from_initializer_list_(init_list);
+    return *this;
+  }
+
   // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
     cleanup_();

platformio.ini

@@ -46,6 +46,10 @@ lib_deps =
     ; This is using the repository until a new release is published to PlatformIO
     https://github.com/Sensirion/arduino-gas-index-algorithm.git#3.2.1 ; Sensirion Gas Index Algorithm Arduino Library
     lvgl/lvgl@8.4.0                                       ; lvgl
+    ; This dependency is used only in unit tests.
+    ; Must coincide with PLATFORMIO_GOOGLE_TEST_LIB in scripts/cpp_unit_test.py
+    ; See scripts/cpp_unit_test.py and tests/components/README.md
+    google/googletest@^1.15.2
 build_flags =
     -DESPHOME_LOG_LEVEL=ESPHOME_LOG_LEVEL_VERY_VERBOSE
     -std=gnu++20

script/cpp_unit_test.py

@@ -0,0 +1,172 @@
+#!/usr/bin/env python3
+import argparse
+import hashlib
+import os
+from pathlib import Path
+import subprocess
+import sys
+
+from helpers import get_all_components, get_all_dependencies, root_path
+
+from esphome.__main__ import command_compile, parse_args
+from esphome.config import validate_config
+from esphome.core import CORE
+from esphome.platformio_api import get_idedata
+
+# This must coincide with the version in /platformio.ini
+PLATFORMIO_GOOGLE_TEST_LIB = "google/googletest@^1.15.2"
+
+# Path to /tests/components
+COMPONENTS_TESTS_DIR: Path = Path(root_path) / "tests" / "components"
+
+
+def hash_components(components: list[str]) -> str:
+    key = ",".join(components)
+    return hashlib.sha256(key.encode()).hexdigest()[:16]
+
+
+def filter_components_without_tests(components: list[str]) -> list[str]:
+    """Filter out components that do not have a corresponding test file.
+
+    This is done by checking if the component's directory contains at
+    least a .cpp file.
+    """
+    filtered_components: list[str] = []
+    for component in components:
+        test_dir = COMPONENTS_TESTS_DIR / component
+        if test_dir.is_dir() and any(test_dir.glob("*.cpp")):
+            filtered_components.append(component)
+        else:
+            print(
+                f"WARNING: No tests found for component '{component}', skipping.",
+                file=sys.stderr,
+            )
+    return filtered_components
+
+
+def create_test_config(config_name: str, includes: list[str]) -> dict:
+    """Create ESPHome test configuration for C++ unit tests.
+
+    Args:
+        config_name: Unique name for this test configuration
+        includes: List of include folders for the test build
+
+    Returns:
+        Configuration dict for ESPHome
+    """
+    return {
+        "esphome": {
+            "name": config_name,
+            "friendly_name": "CPP Unit Tests",
+            "libraries": PLATFORMIO_GOOGLE_TEST_LIB,
+            "platformio_options": {
+                "build_type": "debug",
+                "build_unflags": [
+                    "-Os",  # remove size-opt flag
+                ],
+                "build_flags": [
+                    "-Og",  # optimize for debug
+                ],
+                "debug_build_flags": [  # only for debug builds
+                    "-g3",  # max debug info
+                    "-ggdb3",
+                ],
+            },
+            "includes": includes,
+        },
+        "host": {},
+        "logger": {"level": "DEBUG"},
+    }
+
+
+def run_tests(selected_components: list[str]) -> int:
+    # Skip tests on Windows
+    if os.name == "nt":
+        print("Skipping esphome tests on Windows", file=sys.stderr)
+        return 1
+
+    # Remove components that do not have tests
+    components = filter_components_without_tests(selected_components)
+
+    if len(components) == 0:
+        print(
+            "No components specified or no tests found for the specified components.",
+            file=sys.stderr,
+        )
+        return 0
+
+    components = sorted(components)
+
+    # Obtain possible dependencies for the requested components:
+    components_with_dependencies = sorted(get_all_dependencies(set(components)))
+
+    # Build a list of include folders, one folder per component containing tests.
+    # A special replacement main.cpp is located in /tests/components/main.cpp
+    includes: list[str] = ["main.cpp"] + components
+
+    # Create a unique name for this config based on the actual components being tested
+    # to maximize cache during testing
+    config_name: str = "cpptests-" + hash_components(components)
+
+    config = create_test_config(config_name, includes)
+
+    CORE.config_path = COMPONENTS_TESTS_DIR / "dummy.yaml"
+    CORE.dashboard = None
+
+    # Validate config will expand the above with defaults:
+    config = validate_config(config, {})
+
+    # Add all components and dependencies to the base configuration after validation, so their files
+    # are added to the build.
+    config.update({key: {} for key in components_with_dependencies})
+
+    print(f"Testing components: {', '.join(components)}")
+    CORE.config = config
+    args = parse_args(["program", "compile", str(CORE.config_path)])
+    try:
+        exit_code: int = command_compile(args, config)
+
+        if exit_code != 0:
+            print(f"Error compiling unit tests for {', '.join(components)}")
+            return exit_code
+    except Exception as e:
+        print(
+            f"Error compiling unit tests for {', '.join(components)}. Check path. : {e}"
+        )
+        return 2
+
+    # After a successful compilation, locate the executable and run it:
+    idedata = get_idedata(config)
+    if idedata is None:
+        print("Cannot find executable")
+        return 1
+
+    program_path: str = idedata.raw["prog_path"]
+    run_cmd: list[str] = [program_path]
+    run_proc = subprocess.run(run_cmd, check=False)
+    return run_proc.returncode
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Run C++ unit tests for ESPHome components."
+    )
+    parser.add_argument(
+        "components",
+        nargs="*",
+        help="List of components to test. Use --all to test all known components.",
+    )
+    parser.add_argument("--all", action="store_true", help="Test all known components.")
+
+    args = parser.parse_args()
+
+    if args.all:
+        components: list[str] = get_all_components()
+    else:
+        components: list[str] = args.components
+
+    sys.exit(run_tests(components))
+
+
+if __name__ == "__main__":
+    main()

script/determine-jobs.py

@@ -52,13 +52,16 @@ from helpers import (
     CPP_FILE_EXTENSIONS,
     PYTHON_FILE_EXTENSIONS,
     changed_files,
-    filter_component_files,
+    core_changed,
+    filter_component_and_test_cpp_files,
+    filter_component_and_test_files,
     get_all_dependencies,
     get_changed_components,
     get_component_from_path,
     get_component_test_files,
     get_components_from_integration_fixtures,
     get_components_with_dependencies,
+    get_cpp_changed_components,
     git_ls_files,
     parse_test_filename,
     root_path,
@@ -143,10 +146,9 @@ def should_run_integration_tests(branch: str | None = None) -> bool:
     """
     files = changed_files(branch)
 
-    # Check if any core files changed (esphome/core/*)
-    for file in files:
-        if file.startswith("esphome/core/"):
-            return True
+    if core_changed(files):
+        # If any core files changed, run integration tests
+        return True
 
     # Check if any integration test files changed
     if any("tests/integration" in file for file in files):
@@ -283,6 +285,40 @@ def should_run_python_linters(branch: str | None = None) -> bool:
     return _any_changed_file_endswith(branch, PYTHON_FILE_EXTENSIONS)
 
 
+def determine_cpp_unit_tests(
+    branch: str | None = None,
+) -> tuple[bool, list[str]]:
+    """Determine if C++ unit tests should run based on changed files.
+
+    This function is used by the CI workflow to skip C++ unit tests when
+    no relevant files have changed, saving CI time and resources.
+
+    C++ unit tests will run when any of the following conditions are met:
+
+    1. Any C++ core source files changed (esphome/core/*), in which case
+       all cpp unit tests run.
+    2. A test file for a component changed, which triggers tests for that
+       component.
+    3. The code for a component changed, which triggers tests for that
+       component and all components that depend on it.
+
+    Args:
+        branch: Branch to compare against. If None, uses default.
+
+    Returns:
+        Tuple of (run_all, components) where:
+        - run_all: True if all tests should run, False otherwise
+        - components: List of specific components to test (empty if run_all)
+    """
+    files = changed_files(branch)
+    if core_changed(files):
+        return (True, [])
+
+    # Filter to only C++ files
+    cpp_files = list(filter(filter_component_and_test_cpp_files, files))
+    return (False, get_cpp_changed_components(cpp_files))
+
+
 def _any_changed_file_endswith(branch: str | None, extensions: tuple[str, ...]) -> bool:
     """Check if a changed file ends with any of the specified extensions."""
     return any(file.endswith(extensions) for file in changed_files(branch))
@@ -570,21 +606,23 @@ def main() -> None:
     #   [list]: Changed components (already includes dependencies)
     changed_components_result = get_changed_components()
 
+    # Always analyze component files, even if core files changed
+    # This is needed for component testing and memory impact analysis
+    changed = changed_files(args.branch)
+    component_files = [f for f in changed if filter_component_and_test_files(f)]
+
+    directly_changed_components = get_components_with_dependencies(
+        component_files, False
+    )
+
     if changed_components_result is None:
         # Core files changed - will trigger full clang-tidy scan
-        # No specific components to test
-        changed_components = []
-        directly_changed_components = []
+        # But we still need to track changed components for testing and memory analysis
+        changed_components = get_components_with_dependencies(component_files, True)
         is_core_change = True
     else:
-        # Get both directly changed and all changed (with dependencies)
-        changed = changed_files(args.branch)
-        component_files = [f for f in changed if filter_component_files(f)]
-
-        directly_changed_components = get_components_with_dependencies(
-            component_files, False
-        )
-        changed_components = get_components_with_dependencies(component_files, True)
+        # Use the result from get_changed_components() which includes dependencies
+        changed_components = changed_components_result
         is_core_change = False
 
     # Filter to only components that have test files
@@ -646,6 +684,9 @@ def main() -> None:
         files_to_check_count = 0
 
     # Build output
+    # Determine which C++ unit tests to run
+    cpp_run_all, cpp_components = determine_cpp_unit_tests(args.branch)
+
     output: dict[str, Any] = {
         "integration_tests": run_integration,
         "clang_tidy": run_clang_tidy,
@@ -661,6 +702,8 @@ def main() -> None:
         "dependency_only_count": len(dependency_only_components),
         "changed_cpp_file_count": changed_cpp_file_count,
         "memory_impact": memory_impact,
+        "cpp_unit_tests_run_all": cpp_run_all,
+        "cpp_unit_tests_components": cpp_components,
     }
 
     # Output as JSON

script/extract_automations.py

@@ -2,19 +2,14 @@
 
 import json
 
-from helpers import git_ls_files
+from helpers import get_all_component_files, get_components_with_dependencies
 
 from esphome.automation import ACTION_REGISTRY, CONDITION_REGISTRY
 from esphome.pins import PIN_SCHEMA_REGISTRY
 
-list_components = __import__("list-components")
-
-
 if __name__ == "__main__":
-    files = git_ls_files()
-    files = filter(list_components.filter_component_files, files)
-
-    components = list_components.get_components(files, True)
+    files = get_all_component_files()
+    components = get_components_with_dependencies(files, True)
 
     dump = {
         "actions": sorted(list(ACTION_REGISTRY.keys())),

script/helpers.py

@@ -25,12 +25,21 @@ CPP_FILE_EXTENSIONS = (".cpp", ".h", ".hpp", ".cc", ".cxx", ".c", ".tcc")
 # Python file extensions
 PYTHON_FILE_EXTENSIONS = (".py", ".pyi")
 
+# Combined C++ and Python file extensions for convenience
+CPP_AND_PYTHON_FILE_EXTENSIONS = (*CPP_FILE_EXTENSIONS, *PYTHON_FILE_EXTENSIONS)
+
 # YAML file extensions
 YAML_FILE_EXTENSIONS = (".yaml", ".yml")
 
 # Component path prefix
 ESPHOME_COMPONENTS_PATH = "esphome/components/"
 
+# Test components path prefix
+ESPHOME_TESTS_COMPONENTS_PATH = "tests/components/"
+
+# Tuple of component and test paths for efficient startswith checks
+COMPONENT_AND_TESTS_PATHS = (ESPHOME_COMPONENTS_PATH, ESPHOME_TESTS_COMPONENTS_PATH)
+
 # Base bus components - these ARE the bus implementations and should not
 # be flagged as needing migration since they are the platform/base components
 BASE_BUS_COMPONENTS = {
@@ -658,17 +667,32 @@ def get_components_from_integration_fixtures() -> set[str]:
     return components
 
 
-def filter_component_files(file_path: str) -> bool:
-    """Check if a file path is a component file.
+def filter_component_and_test_files(file_path: str) -> bool:
+    """Check if a file path is a component or test file.
 
     Args:
         file_path: Path to check
 
     Returns:
-        True if the file is in a component directory
+        True if the file is in a component or test directory
     """
-    return file_path.startswith("esphome/components/") or file_path.startswith(
-        "tests/components/"
+    return file_path.startswith(COMPONENT_AND_TESTS_PATHS) or (
+        file_path.startswith(ESPHOME_TESTS_COMPONENTS_PATH)
+        and file_path.endswith(YAML_FILE_EXTENSIONS)
+    )
+
+
+def filter_component_and_test_cpp_files(file_path: str) -> bool:
+    """Check if a file is a C++ source file in component or test directories.
+
+    Args:
+        file_path: Path to check
+
+    Returns:
+        True if the file is a C++ source/header file in component or test directories
+    """
+    return file_path.endswith(CPP_FILE_EXTENSIONS) and file_path.startswith(
+        COMPONENT_AND_TESTS_PATHS
     )
 
 
@@ -740,7 +764,7 @@ def create_components_graph() -> dict[str, list[str]]:
 
     # The root directory of the repo
     root = Path(__file__).parent.parent
-    components_dir = root / "esphome" / "components"
+    components_dir = root / ESPHOME_COMPONENTS_PATH
     # Fake some directory so that get_component works
     CORE.config_path = root
     # Various configuration to capture different outcomes used by `AUTO_LOAD` function.
@@ -873,3 +897,81 @@ def get_components_with_dependencies(
         return sorted(all_changed_components)
 
     return sorted(components)
+
+
+def get_all_component_files() -> list[str]:
+    """Get all component and test files from git.
+
+    Returns:
+        List of all component and test file paths
+    """
+    files = git_ls_files()
+    return list(filter(filter_component_and_test_files, files))
+
+
+def get_all_components() -> list[str]:
+    """Get all component names.
+
+    This function uses git to find all component files and extracts the component names.
+    It returns the same list as calling list-components.py without arguments.
+
+    Returns:
+        List of all component names
+    """
+    return get_components_with_dependencies(get_all_component_files(), False)
+
+
+def core_changed(files: list[str]) -> bool:
+    """Check if any core C++ or Python files have changed.
+
+    Args:
+        files: List of file paths to check
+
+    Returns:
+        True if any core C++ or Python files have changed
+    """
+    return any(
+        f.startswith("esphome/core/") and f.endswith(CPP_AND_PYTHON_FILE_EXTENSIONS)
+        for f in files
+    )
+
+
+def get_cpp_changed_components(files: list[str]) -> list[str]:
+    """Get components that have changed C++ files or tests.
+
+    This function analyzes a list of changed files and determines which components
+    are affected. It handles two scenarios:
+
+    1. Test files changed (tests/components/<component>/*.cpp):
+       - Adds the component to the affected list
+       - Only that component needs to be tested
+
+    2. Component C++ files changed (esphome/components/<component>/*):
+       - Adds the component to the affected list
+       - Also adds all components that depend on this component (recursively)
+       - This ensures that changes propagate to dependent components
+
+    Args:
+        files: List of file paths to analyze (should be C++ files)
+
+    Returns:
+        Sorted list of component names that need C++ unit tests run
+    """
+    components_graph = create_components_graph()
+    affected: set[str] = set()
+    for file in files:
+        if not file.endswith(CPP_FILE_EXTENSIONS):
+            continue
+        if file.startswith(ESPHOME_TESTS_COMPONENTS_PATH):
+            parts = file.split("/")
+            if len(parts) >= 4:
+                component_dir = Path(ESPHOME_TESTS_COMPONENTS_PATH) / parts[2]
+                if component_dir.is_dir():
+                    affected.add(parts[2])
+        elif file.startswith(ESPHOME_COMPONENTS_PATH):
+            parts = file.split("/")
+            if len(parts) >= 4:
+                component = parts[2]
+                affected.update(find_children_of_component(components_graph, component))
+                affected.add(component)
+    return sorted(affected)

script/list-components.py

@@ -3,18 +3,14 @@ import argparse
 
 from helpers import (
     changed_files,
-    filter_component_files,
+    filter_component_and_test_cpp_files,
+    filter_component_and_test_files,
+    get_all_component_files,
     get_components_with_dependencies,
-    git_ls_files,
+    get_cpp_changed_components,
 )
 
 
-def get_all_component_files() -> list[str]:
-    """Get all component files from git."""
-    files = git_ls_files()
-    return list(filter(filter_component_files, files))
-
-
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument(
@@ -39,16 +35,29 @@ def main():
     parser.add_argument(
         "-b", "--branch", help="Branch to compare changed files against"
     )
+    parser.add_argument(
+        "--cpp-changed",
+        action="store_true",
+        help="List components with changed C++ files",
+    )
     args = parser.parse_args()
 
     if args.branch and not (
-        args.changed or args.changed_direct or args.changed_with_deps
+        args.changed
+        or args.changed_direct
+        or args.changed_with_deps
+        or args.cpp_changed
     ):
         parser.error(
-            "--branch requires --changed, --changed-direct, or --changed-with-deps"
+            "--branch requires --changed, --changed-direct, --changed-with-deps, or --cpp-changed"
         )
 
-    if args.changed or args.changed_direct or args.changed_with_deps:
+    if (
+        args.changed
+        or args.changed_direct
+        or args.changed_with_deps
+        or args.cpp_changed
+    ):
         # When --changed* is passed, only get the changed files
         changed = changed_files(args.branch)
 
@@ -68,6 +77,11 @@ def main():
         # - --changed-with-deps: Used by CI test determination (script/determine-jobs.py)
         #   Returns: Components with code changes + their dependencies (not infrastructure)
         #   Reason: CI needs to test changed components and their dependents
+        #
+        # - --cpp-changed: Used by CI to determine if any C++ files changed (script/determine-jobs.py)
+        #   Returns: Only components with changed C++ files
+        #   Reason: Only components with C++ changes need C++ testing
+
         base_test_changed = any(
             "tests/test_build_components" in file for file in changed
         )
@@ -80,7 +94,7 @@ def main():
             # Only look at changed component files (ignore infrastructure changes)
             # For --changed-direct: only actual component code changes matter (for isolation)
             # For --changed-with-deps: only actual component code changes matter (for testing)
-            files = [f for f in changed if filter_component_files(f)]
+            files = [f for f in changed if filter_component_and_test_files(f)]
     else:
         # Get all component files
         files = get_all_component_files()
@@ -100,6 +114,11 @@ def main():
         # Return only directly changed components (without dependencies)
         for c in get_components_with_dependencies(files, False):
             print(c)
+    elif args.cpp_changed:
+        # Only look at changed cpp files
+        files = list(filter(filter_component_and_test_cpp_files, changed))
+        for c in get_cpp_changed_components(files):
+            print(c)
     else:
         # Return all changed components (with dependencies) - default behavior
         for c in get_components_with_dependencies(files, args.changed):

tests/components/.gitignore

@@ -0,0 +1,5 @@
+# Gitignore settings for ESPHome
+# This is an example and may include too much for your use-case.
+# You can modify this file to suit your needs.
+/.esphome/
+/secrets.yaml

tests/components/README.md

@@ -0,0 +1,32 @@
+# How to write C++ ESPHome unit tests
+
+1. Locate the folder with your component or create a new one with the same name as the component.
+2. Write the tests. You can add as many `.cpp` and `.h` files as you need to organize your tests.
+
+**IMPORTANT**: wrap all your testing code in a unique namespace to avoid linker collisions when compiling
+testing binaries that combine many components. By convention, this unique namespace is `esphome::component::testing`
+(where "component" is the component under test), for example: `esphome::uart::testing`.
+
+
+## Running component unit tests
+
+(from the repository root)
+```bash
+./script/cpp_unit_test.py component1 component2 ...
+```
+
+The above will compile and run the provided components and their tests.
+
+To run all tests, you can invoke `cpp_unit_test.py` with the special `--all` flag:
+
+```bash
+./script/cpp_unit_test.py --all
+```
+
+To run a specific test suite, you can provide a Google Test filter:
+
+```bash
+GTEST_FILTER='UART*' ./script/cpp_unit_test.py uart modbus
+```
+
+The process will return `0` for success or nonzero for failure. In case of failure, the errors will be printed out to the console.

tests/components/binary_sensor/common.yaml

@@ -70,3 +70,69 @@ binary_sensor:
           - delay: 10s
             time_off: 200ms
             time_on: 800ms
+
+  # Test on_multi_click with single click
+  - platform: template
+    id: multi_click_single
+    name: "Multi Click Single"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+        then:
+          - logger.log: "Single click detected"
+
+  # Test on_multi_click with double click
+  - platform: template
+    id: multi_click_double
+    name: "Multi Click Double"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+        then:
+          - logger.log: "Double click detected"
+
+  # Test on_multi_click with complex pattern (5 events)
+  - platform: template
+    id: multi_click_complex
+    name: "Multi Click Complex"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+        then:
+          - logger.log: "Complex pattern detected"
+
+  # Test on_multi_click with custom invalid_cooldown
+  - platform: template
+    id: multi_click_cooldown
+    name: "Multi Click Cooldown"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 100ms
+            max_length: 500ms
+        invalid_cooldown: 2s
+        then:
+          - logger.log: "Click with custom cooldown"

tests/components/gpio/common.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: ${switch_pin}
     id: gpio_switch
+
+  - platform: gpio
+    pin: ${switch_pin_2}
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: ${switch_pin_3}
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: ${switch_pin_4}
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.esp32-c3-idf.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO2
   output_pin: GPIO3
   switch_pin: GPIO4
+  switch_pin_2: GPIO5
+  switch_pin_3: GPIO6
+  switch_pin_4: GPIO7
 
 <<: !include common.yaml

tests/components/gpio/test.esp32-idf.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO12
   output_pin: GPIO13
   switch_pin: GPIO14
+  switch_pin_2: GPIO15
+  switch_pin_3: GPIO16
+  switch_pin_4: GPIO17
 
 <<: !include common.yaml

tests/components/gpio/test.esp8266-ard.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO0
   output_pin: GPIO2
   switch_pin: GPIO15
+  switch_pin_2: GPIO12
+  switch_pin_3: GPIO13
+  switch_pin_4: GPIO14
 
 <<: !include common.yaml

tests/components/gpio/test.nrf52-adafruit.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: P1.2
     id: gpio_switch
+
+  - platform: gpio
+    pin: P1.3
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: P1.4
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: P1.5
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.nrf52-mcumgr.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: P1.2
     id: gpio_switch
+
+  - platform: gpio
+    pin: P1.3
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: P1.4
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: P1.5
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.rp2040-ard.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO2
   output_pin: GPIO3
   switch_pin: GPIO4
+  switch_pin_2: GPIO5
+  switch_pin_3: GPIO6
+  switch_pin_4: GPIO7
 
 <<: !include common.yaml

tests/components/light/common.yaml

@@ -17,6 +17,20 @@ esphome:
           relative_brightness: 5%
           brightness_limits:
             max_brightness: 90%
+      - light.turn_on:
+          id: test_addressable_transition
+          brightness: 50%
+          red: 100%
+          green: 0%
+          blue: 0%
+          transition_length: 500ms
+      - light.turn_on:
+          id: test_addressable_transition
+          brightness: 100%
+          red: 0%
+          green: 100%
+          blue: 0%
+          transition_length: 1s
 
 light:
   - platform: binary
@@ -123,3 +137,49 @@ light:
       red: 100%
       green: 50%
       blue: 50%
+  # Test StrobeLightEffect with multiple colors
+  - platform: monochromatic
+    id: test_strobe_multiple
+    name: Strobe Multiple Colors
+    output: test_ledc_1
+    effects:
+      - strobe:
+          name: Strobe Multi
+          colors:
+            - state: true
+              brightness: 100%
+              duration: 500ms
+            - state: false
+              duration: 250ms
+            - state: true
+              brightness: 50%
+              duration: 500ms
+  # Test StrobeLightEffect with transition
+  - platform: rgb
+    id: test_strobe_transition
+    name: Strobe With Transition
+    red: test_ledc_1
+    green: test_ledc_2
+    blue: test_ledc_3
+    effects:
+      - strobe:
+          name: Strobe Transition
+          colors:
+            - state: true
+              red: 100%
+              green: 0%
+              blue: 0%
+              duration: 1s
+              transition_length: 500ms
+            - state: true
+              red: 0%
+              green: 100%
+              blue: 0%
+              duration: 1s
+              transition_length: 500ms
+  - platform: partition
+    id: test_addressable_transition
+    name: Addressable Transition Test
+    default_transition_length: 1s
+    segments:
+      - single_light_id: test_rgb_light

tests/components/main.cpp

@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+/*
+This special main.cpp replaces the default one.
+It will run all the Google Tests found in all compiled cpp files and then exit with the result
+See README.md for more information
+*/
+
+// Auto generated code by esphome
+// ========== AUTO GENERATED INCLUDE BLOCK BEGIN ===========
+// ========== AUTO GENERATED INCLUDE BLOCK END ==========="
+
+void original_setup() {
+  // This function won't be run.
+
+  // ========== AUTO GENERATED CODE BEGIN ===========
+  // =========== AUTO GENERATED CODE END ============
+}
+
+void setup() {
+  ::testing::InitGoogleTest();
+  int exit_code = RUN_ALL_TESTS();
+  exit(exit_code);
+}
+
+void loop() {}

tests/components/uart/common.h

@@ -0,0 +1,37 @@
+#pragma once
+#include <vector>
+#include <cstdint>
+#include <cstring>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include "esphome/components/uart/uart_component.h"
+
+namespace esphome::uart::testing {
+
+using ::testing::_;
+using ::testing::Return;
+using ::testing::SaveArg;
+using ::testing::DoAll;
+using ::testing::Invoke;
+using ::testing::SetArgPointee;
+
+// Derive a mock from UARTComponent to test the wrapper implementations.
+class MockUARTComponent : public UARTComponent {
+ public:
+  using UARTComponent::write_array;
+  using UARTComponent::write_byte;
+
+  // NOTE: std::vector is used here for test convenience. For production code,
+  // consider using StaticVector or FixedVector from esphome/core/helpers.h instead.
+  std::vector<uint8_t> written_data;
+
+  void write_array(const uint8_t *data, size_t len) override { written_data.assign(data, data + len); }
+
+  MOCK_METHOD(bool, read_array, (uint8_t * data, size_t len), (override));
+  MOCK_METHOD(bool, peek_byte, (uint8_t * data), (override));
+  MOCK_METHOD(int, available, (), (override));
+  MOCK_METHOD(void, flush, (), (override));
+  MOCK_METHOD(void, check_logger_conflict, (), (override));
+};
+
+}  // namespace esphome::uart::testing

tests/components/uart/uart_component.cpp

@@ -0,0 +1,73 @@
+#include "common.h"
+
+namespace esphome::uart::testing {
+
+TEST(UARTComponentTest, SetGetBaudRate) {
+  MockUARTComponent mock;
+  mock.set_baud_rate(38400);
+  EXPECT_EQ(mock.get_baud_rate(), 38400);
+}
+
+TEST(UARTComponentTest, SetGetStopBits) {
+  MockUARTComponent mock;
+  mock.set_stop_bits(2);
+  EXPECT_EQ(mock.get_stop_bits(), 2);
+}
+
+TEST(UARTComponentTest, SetGetDataBits) {
+  MockUARTComponent mock;
+  mock.set_data_bits(7);
+  EXPECT_EQ(mock.get_data_bits(), 7);
+}
+
+TEST(UARTComponentTest, SetGetParity) {
+  MockUARTComponent mock;
+  mock.set_parity(UARTParityOptions::UART_CONFIG_PARITY_EVEN);
+  EXPECT_EQ(mock.get_parity(), UARTParityOptions::UART_CONFIG_PARITY_EVEN);
+}
+
+TEST(UARTComponentTest, SetGetRxBufferSize) {
+  MockUARTComponent mock;
+  mock.set_rx_buffer_size(128);
+  EXPECT_EQ(mock.get_rx_buffer_size(), 128);
+}
+
+TEST(UARTComponentTest, WriteArrayVector) {
+  MockUARTComponent mock;
+  std::vector<uint8_t> data = {10, 20, 30};
+  mock.write_array(data);
+  EXPECT_EQ(mock.written_data, data);
+}
+TEST(UARTComponentTest, WriteByte) {
+  MockUARTComponent mock;
+  uint8_t byte = 0x79;
+  mock.write_byte(byte);
+  EXPECT_EQ(mock.written_data.size(), 1);
+  EXPECT_EQ(mock.written_data[0], byte);
+}
+
+TEST(UARTComponentTest, WriteStr) {
+  MockUARTComponent mock;
+  const char *str = "Hello";
+  std::vector<uint8_t> captured;
+  mock.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), strlen(str));
+  EXPECT_EQ(0, strncmp(str, (const char *) mock.written_data.data(), mock.written_data.size()));
+}
+
+// Tests for wrapper methods forwarding to pure virtual read_array
+TEST(UARTComponentTest, ReadByteSuccess) {
+  MockUARTComponent mock;
+  uint8_t value = 0;
+  EXPECT_CALL(mock, read_array(&value, 1)).WillOnce(Return(true));
+  EXPECT_TRUE(mock.read_byte(&value));
+}
+
+TEST(UARTComponentTest, ReadByteFailure) {
+  MockUARTComponent mock;
+  uint8_t value = 0xFF;
+  EXPECT_CALL(mock, read_array(&value, 1)).WillOnce(Return(false));
+  EXPECT_FALSE(mock.read_byte(&value));
+}
+
+}  // namespace esphome::uart::testing

tests/components/uart/uart_device.cpp

@@ -0,0 +1,108 @@
+#include "common.h"
+#include "esphome/components/uart/uart.h"
+
+namespace esphome::uart::testing {
+
+TEST(UARTDeviceTest, ReadByteSuccess) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, read_array(_, 1)).WillOnce(DoAll(SetArgPointee<0>(0x5A), Return(true)));
+  bool result = dev.read_byte(&value);
+  EXPECT_TRUE(result);
+  EXPECT_EQ(value, 0x5A);
+}
+
+TEST(UARTDeviceTest, ReadByteFailure) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0xFF;
+  EXPECT_CALL(mock, read_array(_, 1)).WillOnce(Return(false));
+  bool result = dev.read_byte(&value);
+  EXPECT_FALSE(result);
+}
+
+TEST(UARTDeviceTest, PeekByteSuccess) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, peek_byte(_)).WillOnce(DoAll(SetArgPointee<0>(0xA5), Return(true)));
+  bool result = dev.peek_byte(&value);
+  EXPECT_TRUE(result);
+  EXPECT_EQ(value, 0xA5);
+}
+
+TEST(UARTDeviceTest, PeekByteFailure) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, peek_byte(_)).WillOnce(Return(false));
+  bool result = dev.peek_byte(&value);
+  EXPECT_FALSE(result);
+}
+
+TEST(UARTDeviceTest, Available) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  EXPECT_CALL(mock, available()).WillOnce(Return(5));
+  EXPECT_EQ(dev.available(), 5);
+}
+
+TEST(UARTDeviceTest, FlushCallsParent) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  EXPECT_CALL(mock, flush()).Times(1);
+  dev.flush();
+}
+
+TEST(UARTDeviceTest, WriteByteForwardsToWriteArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  dev.write_byte(0xAB);
+  EXPECT_EQ(mock.written_data.size(), 1);
+  EXPECT_EQ(mock.written_data[0], 0xAB);
+}
+TEST(UARTDeviceTest, WriteArrayPointer) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t data[3] = {1, 2, 3};
+  dev.write_array(data, 3);
+  EXPECT_EQ(mock.written_data.size(), 3);
+  EXPECT_EQ(mock.written_data, std::vector(data, data + 3));
+}
+
+TEST(UARTDeviceTest, WriteArrayVector) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  std::vector<uint8_t> data = {4, 5, 6};
+  dev.write_array(data);
+  EXPECT_EQ(mock.written_data, data);
+}
+
+TEST(UARTDeviceTest, WriteArrayStdArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  std::array<uint8_t, 4> data = {7, 8, 9, 10};
+  dev.write_array(data);
+  EXPECT_EQ(mock.written_data.size(), data.size());
+  EXPECT_EQ(mock.written_data, std::vector(data.begin(), data.end()));
+}
+
+TEST(UARTDeviceTest, WriteStrForwardsToWriteArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  const char *str = "ESPHome";
+  dev.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), strlen(str));
+  EXPECT_EQ(0, strncmp(str, (const char *) mock.written_data.data(), mock.written_data.size()));
+}
+
+TEST(UARTDeviceTest, WriteStrEmptyString) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  const char *str = "";
+  dev.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), 0);
+}
+
+}  // namespace esphome::uart::testing

tests/components/wifi/common.yaml

@@ -12,5 +12,8 @@ esphome:
             - logger.log: "Failed to connect to WiFi!"
 
 wifi:
-  ssid: MySSID
-  password: password1
+  networks:
+    - ssid: MySSID
+      password: password1
+    - ssid: MySSID2
+      password: password2

tests/integration/fixtures/noise_encryption_key_clear_protection.yaml

@@ -0,0 +1,10 @@
+esphome:
+  name: noise-key-test
+
+host:
+
+api:
+  encryption:
+    key: "zX9/JHxMKwpP0jUGsF0iESCm1wRvNgR6NkKVOhn7kSs="
+
+logger:

tests/integration/test_noise_encryption_key_protection.py

@@ -49,3 +49,42 @@ async def test_noise_encryption_key_protection(
         with pytest.raises(InvalidEncryptionKeyAPIError):
             async with api_client_connected(noise_psk=wrong_key) as client:
                 await client.device_info()
+
+
+@pytest.mark.asyncio
+async def test_noise_encryption_key_clear_protection(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that noise encryption key set in YAML cannot be changed via API."""
+    # The key that's set in the YAML fixture
+    noise_psk = "zX9/JHxMKwpP0jUGsF0iESCm1wRvNgR6NkKVOhn7kSs="
+
+    # Keep ESPHome process running throughout all tests
+    async with run_compiled(yaml_config):
+        # First connection - test key change attempt
+        async with api_client_connected(noise_psk=noise_psk) as client:
+            # Verify connection is established
+            device_info = await client.device_info()
+            assert device_info is not None
+
+            # Try to set a new encryption key via API
+            new_key = b""  # Empty key to attempt to clear
+
+            # This should fail since key was set in YAML
+            success = await client.noise_encryption_set_key(new_key)
+            assert success is False
+
+        # Reconnect with the original key to verify it still works
+        async with api_client_connected(noise_psk=noise_psk) as client:
+            # Verify connection is still successful with original key
+            device_info = await client.device_info()
+            assert device_info is not None
+            assert device_info.name == "noise-key-test"
+
+        # Verify that connecting with a wrong key fails
+        wrong_key = base64.b64encode(b"y" * 32).decode()  # Different key
+        with pytest.raises(InvalidEncryptionKeyAPIError):
+            async with api_client_connected(noise_psk=wrong_key) as client:
+                await client.device_info()

tests/script/test_determine_jobs.py

@@ -5,7 +5,6 @@ import importlib.util
 import json
 import os
 from pathlib import Path
-import subprocess
 import sys
 from unittest.mock import Mock, call, patch
 
@@ -56,9 +55,9 @@ def mock_should_run_python_linters() -> Generator[Mock, None, None]:
 
 
 @pytest.fixture
-def mock_subprocess_run() -> Generator[Mock, None, None]:
-    """Mock subprocess.run for list-components.py calls."""
-    with patch.object(determine_jobs.subprocess, "run") as mock:
+def mock_determine_cpp_unit_tests() -> Generator[Mock, None, None]:
+    """Mock determine_cpp_unit_tests from helpers."""
+    with patch.object(determine_jobs, "determine_cpp_unit_tests") as mock:
         yield mock
 
 
@@ -82,8 +81,8 @@ def test_main_all_tests_should_run(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -95,6 +94,7 @@ def test_main_all_tests_should_run(
     mock_should_run_clang_tidy.return_value = True
     mock_should_run_clang_format.return_value = True
     mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (False, ["wifi", "api", "sensor"])
 
     # Mock changed_files to return non-component files (to avoid memory impact)
     # Memory impact only runs when component C++ files change
@@ -114,15 +114,15 @@ def test_main_all_tests_should_run(
         ),
         patch.object(
             determine_jobs,
-            "filter_component_files",
+            "filter_component_and_test_files",
             side_effect=lambda f: f.startswith("esphome/components/"),
         ),
         patch.object(
             determine_jobs,
             "get_components_with_dependencies",
-            side_effect=lambda files, deps: ["wifi", "api"]
-            if not deps
-            else ["wifi", "api", "sensor"],
+            side_effect=lambda files, deps: (
+                ["wifi", "api"] if not deps else ["wifi", "api", "sensor"]
+            ),
         ),
     ):
         determine_jobs.main()
@@ -150,6 +150,8 @@ def test_main_all_tests_should_run(
     # memory_impact should be false (no component C++ files changed)
     assert "memory_impact" in output
     assert output["memory_impact"]["should_run"] == "false"
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == ["wifi", "api", "sensor"]
 
 
 def test_main_no_tests_should_run(
@@ -157,8 +159,8 @@ def test_main_no_tests_should_run(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -170,6 +172,7 @@ def test_main_no_tests_should_run(
     mock_should_run_clang_tidy.return_value = False
     mock_should_run_clang_format.return_value = False
     mock_should_run_python_linters.return_value = False
+    mock_determine_cpp_unit_tests.return_value = (False, [])
 
     # Mock changed_files to return no component files
     mock_changed_files.return_value = []
@@ -178,7 +181,9 @@ def test_main_no_tests_should_run(
     with (
         patch("sys.argv", ["determine-jobs.py"]),
         patch.object(determine_jobs, "get_changed_components", return_value=[]),
-        patch.object(determine_jobs, "filter_component_files", return_value=False),
+        patch.object(
+            determine_jobs, "filter_component_and_test_files", return_value=False
+        ),
         patch.object(
             determine_jobs, "get_components_with_dependencies", return_value=[]
         ),
@@ -202,31 +207,8 @@ def test_main_no_tests_should_run(
     # memory_impact should be present
     assert "memory_impact" in output
     assert output["memory_impact"]["should_run"] == "false"
-
-
-def test_main_list_components_fails(
-    mock_should_run_integration_tests: Mock,
-    mock_should_run_clang_tidy: Mock,
-    mock_should_run_clang_format: Mock,
-    mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """Test when list-components.py fails."""
-    mock_should_run_integration_tests.return_value = True
-    mock_should_run_clang_tidy.return_value = True
-    mock_should_run_clang_format.return_value = True
-    mock_should_run_python_linters.return_value = True
-
-    # Mock list-components.py failure
-    mock_subprocess_run.side_effect = subprocess.CalledProcessError(1, "cmd")
-
-    # Run main function with mocked argv - should raise
-    with (
-        patch("sys.argv", ["determine-jobs.py"]),
-        pytest.raises(subprocess.CalledProcessError),
-    ):
-        determine_jobs.main()
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == []
 
 
 def test_main_with_branch_argument(
@@ -234,8 +216,8 @@ def test_main_with_branch_argument(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -247,6 +229,7 @@ def test_main_with_branch_argument(
     mock_should_run_clang_tidy.return_value = True
     mock_should_run_clang_format.return_value = False
     mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (False, ["mqtt"])
 
     # Mock changed_files to return non-component files (to avoid memory impact)
     # Memory impact only runs when component C++ files change
@@ -258,7 +241,7 @@ def test_main_with_branch_argument(
         patch.object(determine_jobs, "get_changed_components", return_value=["mqtt"]),
         patch.object(
             determine_jobs,
-            "filter_component_files",
+            "filter_component_and_test_files",
             side_effect=lambda f: f.startswith("esphome/components/"),
         ),
         patch.object(
@@ -296,6 +279,8 @@ def test_main_with_branch_argument(
     # memory_impact should be false (no component C++ files changed)
     assert "memory_impact" in output
     assert output["memory_impact"]["should_run"] == "false"
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == ["mqtt"]
 
 
 def test_should_run_integration_tests(
@@ -506,7 +491,6 @@ def test_main_filters_components_without_tests(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
     capsys: pytest.CaptureFixture[str],
     tmp_path: Path,
@@ -556,16 +540,17 @@ def test_main_filters_components_without_tests(
         ),
         patch.object(
             determine_jobs,
-            "filter_component_files",
+            "filter_component_and_test_files",
             side_effect=lambda f: f.startswith("esphome/components/"),
         ),
         patch.object(
             determine_jobs,
             "get_components_with_dependencies",
-            side_effect=lambda files, deps: ["wifi", "sensor"]
-            if not deps
-            else ["wifi", "sensor", "airthings_ble"],
+            side_effect=lambda files, deps: (
+                ["wifi", "sensor"] if not deps else ["wifi", "sensor", "airthings_ble"]
+            ),
         ),
+        patch.object(determine_jobs, "changed_files", return_value=[]),
     ):
         # Clear the cache since we're mocking root_path
         determine_jobs._component_has_tests.cache_clear()
@@ -808,7 +793,6 @@ def test_clang_tidy_mode_full_scan(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
@@ -829,7 +813,9 @@ def test_clang_tidy_mode_full_scan(
         patch("sys.argv", ["determine-jobs.py"]),
         patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=True),
         patch.object(determine_jobs, "get_changed_components", return_value=[]),
-        patch.object(determine_jobs, "filter_component_files", return_value=False),
+        patch.object(
+            determine_jobs, "filter_component_and_test_files", return_value=False
+        ),
         patch.object(
             determine_jobs, "get_components_with_dependencies", return_value=[]
         ),
@@ -873,7 +859,6 @@ def test_clang_tidy_mode_targeted_scan(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
@@ -912,7 +897,7 @@ def test_clang_tidy_mode_targeted_scan(
         patch.object(determine_jobs, "get_changed_components", return_value=components),
         patch.object(
             determine_jobs,
-            "filter_component_files",
+            "filter_component_and_test_files",
             side_effect=lambda f: f.startswith("esphome/components/"),
         ),
         patch.object(
@@ -925,3 +910,60 @@ def test_clang_tidy_mode_targeted_scan(
     output = json.loads(captured.out)
 
     assert output["clang_tidy_mode"] == expected_mode
+
+
+def test_main_core_files_changed_still_detects_components(
+    mock_should_run_integration_tests: Mock,
+    mock_should_run_clang_tidy: Mock,
+    mock_should_run_clang_format: Mock,
+    mock_should_run_python_linters: Mock,
+    mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
+    capsys: pytest.CaptureFixture[str],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test that component changes are detected even when core files change."""
+    monkeypatch.delenv("GITHUB_ACTIONS", raising=False)
+
+    mock_should_run_integration_tests.return_value = True
+    mock_should_run_clang_tidy.return_value = True
+    mock_should_run_clang_format.return_value = True
+    mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (True, [])
+
+    mock_changed_files.return_value = [
+        "esphome/core/helpers.h",
+        "esphome/components/select/select_traits.h",
+        "esphome/components/select/select_traits.cpp",
+        "esphome/components/api/api.proto",
+    ]
+
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=False),
+        patch.object(determine_jobs, "get_changed_components", return_value=None),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs,
+            "get_components_with_dependencies",
+            side_effect=lambda files, deps: (
+                ["select", "api"]
+                if not deps
+                else ["select", "api", "bluetooth_proxy", "logger"]
+            ),
+        ),
+    ):
+        determine_jobs.main()
+
+    captured = capsys.readouterr()
+    output = json.loads(captured.out)
+
+    assert output["clang_tidy"] is True
+    assert output["clang_tidy_mode"] == "split"
+    assert "select" in output["changed_components"]
+    assert "api" in output["changed_components"]
+    assert len(output["changed_components"]) > 0