[fan] Test the speed_count limits in the schemas and in FanTraits

esphome/components/fan/__init__.py

@@ -185,6 +185,10 @@ _PRESET_MODES_SCHEMA = cv.All(
 )
 
 
+# speed_count_ is a uint16_t in FanTraits
+validate_speed_count = cv.int_range(min=1, max=65535)
+
+
 def validate_preset_modes(value):
     # Check against defined schema
     value = _PRESET_MODES_SCHEMA(value)

esphome/components/fan/fan_traits.h

@@ -17,24 +17,24 @@ class FanTraits {
  public:
   FanTraits() = default;
   FanTraits(bool oscillation, bool speed, bool direction, int speed_count)
-      : oscillation_(oscillation), speed_(speed), direction_(direction), speed_count_(speed_count) {}
+      : flags_{oscillation, speed, direction, 0}, speed_count_(speed_count) {}
 
   /// Return if this fan supports oscillation.
-  bool supports_oscillation() const { return this->oscillation_; }
+  bool supports_oscillation() const { return this->flags_.oscillation; }
   /// Set whether this fan supports oscillation.
-  void set_oscillation(bool oscillation) { this->oscillation_ = oscillation; }
+  void set_oscillation(bool oscillation) { this->flags_.oscillation = oscillation; }
   /// Return if this fan supports speed modes.
-  bool supports_speed() const { return this->speed_; }
+  bool supports_speed() const { return this->flags_.speed; }
   /// Set whether this fan supports speed levels.
-  void set_speed(bool speed) { this->speed_ = speed; }
+  void set_speed(bool speed) { this->flags_.speed = speed; }
   /// Return how many speed levels the fan has
   int supported_speed_count() const { return this->speed_count_; }
   /// Set how many speed levels this fan has.
   void set_supported_speed_count(int speed_count) { this->speed_count_ = speed_count; }
   /// Return if this fan supports changing direction
-  bool supports_direction() const { return this->direction_; }
+  bool supports_direction() const { return this->flags_.direction; }
   /// Set whether this fan supports changing direction
-  void set_direction(bool direction) { this->direction_ = direction; }
+  void set_direction(bool direction) { this->flags_.direction = direction; }
   /// Empty when the fan has no preset modes. Set them on the Fan entity.
   const FanPresetModes &supported_preset_modes() const;
 
@@ -60,10 +60,14 @@ class FanTraits {
   /// Set the preset modes pointer (only Fan::wire_preset_modes_() should call this).
   void set_supported_preset_modes_(const FanPresetModes *preset_modes) { this->preset_modes_ = preset_modes; }
 
-  bool oscillation_{false};
-  bool speed_{false};
-  bool direction_{false};
-  int speed_count_{};
+  // Bit-packed flags to save memory (1 byte instead of 3)
+  struct FanTraitFlags {
+    uint8_t oscillation : 1;
+    uint8_t speed : 1;
+    uint8_t direction : 1;
+    uint8_t reserved : 5;
+  } flags_{};
+  uint16_t speed_count_{};                       // validators cap configs at 65535
   const FanPresetModes *preset_modes_{nullptr};  // owned by the Fan entity
 };
 static_assert(std::is_trivially_copyable_v<FanTraits>, "FanTraits is returned by value from get_traits()");

esphome/components/hbridge/fan/__init__.py

@@ -33,7 +33,7 @@ CONFIG_SCHEMA = (
             cv.Optional(CONF_DECAY_MODE, default="SLOW"): cv.enum(
                 DECAY_MODE_OPTIONS, upper=True
             ),
-            cv.Optional(CONF_SPEED_COUNT, default=100): cv.int_range(min=1),
+            cv.Optional(CONF_SPEED_COUNT, default=100): fan.validate_speed_count,
             cv.Optional(CONF_ENABLE_PIN): cv.use_id(output.FloatOutput),
             cv.Optional(CONF_PRESET_MODES): validate_preset_modes,
         }

esphome/components/speed/fan/__init__.py

@@ -26,7 +26,7 @@ CONFIG_SCHEMA = (
             cv.Optional(CONF_SPEED): cv.invalid(
                 "Configuring individual speeds is deprecated."
             ),
-            cv.Optional(CONF_SPEED_COUNT, default=100): cv.int_range(min=1),
+            cv.Optional(CONF_SPEED_COUNT, default=100): fan.validate_speed_count,
             cv.Optional(CONF_PRESET_MODES): validate_preset_modes,
         }
     )

esphome/components/template/fan/__init__.py

@@ -19,7 +19,7 @@ CONFIG_SCHEMA = (
         {
             cv.Optional(CONF_HAS_DIRECTION, default=False): cv.boolean,
             cv.Optional(CONF_HAS_OSCILLATING, default=False): cv.boolean,
-            cv.Optional(CONF_SPEED_COUNT): cv.int_range(min=1),
+            cv.Optional(CONF_SPEED_COUNT): fan.validate_speed_count,
             cv.Optional(CONF_PRESET_MODES): validate_preset_modes,
         }
     )

tests/component_tests/fan/test_speed_count.py

@@ -0,0 +1,38 @@
+"""speed_count must fit the uint16_t FanTraits stores it in."""
+
+from typing import Any
+
+import pytest
+
+from esphome import config_validation as cv
+from esphome.components.hbridge.fan import CONFIG_SCHEMA as HBRIDGE_SCHEMA
+from esphome.components.speed.fan import CONFIG_SCHEMA as SPEED_SCHEMA
+from esphome.components.template.fan import CONFIG_SCHEMA as TEMPLATE_SCHEMA
+from esphome.const import CONF_SPEED_COUNT
+
+SCHEMAS: dict[str, tuple[Any, dict[str, Any]]] = {
+    "speed": (SPEED_SCHEMA, {"name": "Fan", "output": "fan_out"}),
+    "hbridge": (HBRIDGE_SCHEMA, {"name": "Fan", "pin_a": "out_a", "pin_b": "out_b"}),
+    "template": (TEMPLATE_SCHEMA, {"name": "Fan"}),
+}
+
+
+@pytest.mark.parametrize("platform", SCHEMAS)
+@pytest.mark.parametrize("speed_count", [1, 65535])
+def test_speed_count_limits_accepted(platform: str, speed_count: int) -> None:
+    schema, base = SCHEMAS[platform]
+    config = schema({**base, CONF_SPEED_COUNT: speed_count})
+    assert config[CONF_SPEED_COUNT] == speed_count
+
+
+@pytest.mark.parametrize("platform", SCHEMAS)
+@pytest.mark.parametrize("speed_count", [0, 65536])
+def test_speed_count_out_of_range_rejected(platform: str, speed_count: int) -> None:
+    schema, base = SCHEMAS[platform]
+    with pytest.raises(cv.Invalid, match="speed_count|at least|at most"):
+        schema({**base, CONF_SPEED_COUNT: speed_count})
+
+
+def test_template_fan_without_speed_count() -> None:
+    schema, base = SCHEMAS["template"]
+    assert CONF_SPEED_COUNT not in schema(base)

tests/components/fan/fan_test.cpp

@@ -57,4 +57,19 @@ TEST(FanPresetModesTest, TraitsWithoutAFanHaveNoPresets) {
   EXPECT_FALSE(traits.supports_preset_modes());
 }
 
+TEST(FanTraitsTest, SpeedCountKeepsSixteenBits) {
+  FanTraits traits(true, true, false, 65535);
+  EXPECT_EQ(traits.supported_speed_count(), 65535);
+  EXPECT_TRUE(traits.supports_oscillation());
+  EXPECT_TRUE(traits.supports_speed());
+  EXPECT_FALSE(traits.supports_direction());
+  traits.set_supported_speed_count(1);
+  traits.set_direction(true);
+  traits.set_oscillation(false);
+  EXPECT_EQ(traits.supported_speed_count(), 1);
+  EXPECT_TRUE(traits.supports_direction());
+  EXPECT_FALSE(traits.supports_oscillation());
+  EXPECT_TRUE(traits.supports_speed());
+}
+
 }  // namespace esphome::fan::testing