[light] Shrink LightState by 12 bytes per light (#19711)

tests/component_tests/light/test_light_state_layout.py

@@ -0,0 +1,37 @@
+"""Limits and flash layout that let LightState stay small."""
+
+import pytest
+
+from esphome import config_validation as cv
+from esphome.components.light.effects import (
+    MAX_EFFECTS,
+    MONOCHROMATIC_EFFECTS,
+    validate_effects,
+)
+
+
+def _effects(count: int) -> list[dict[str, dict[str, str]]]:
+    return [{"pulse": {"name": f"Pulse {i}"}} for i in range(count)]
+
+
+def test_rejects_more_effects_than_the_index_holds() -> None:
+    with pytest.raises(cv.Invalid, match=f"at most {MAX_EFFECTS} effects"):
+        validate_effects(MONOCHROMATIC_EFFECTS)(_effects(MAX_EFFECTS + 1))
+
+
+def test_accepts_a_normal_effect_list() -> None:
+    assert len(validate_effects(MONOCHROMATIC_EFFECTS)(_effects(3))) == 3
+
+
+def test_gamma_table_initializer_holds_the_lut_then_gamma_times_100() -> None:
+    from esphome.components.light import gamma_table_initializer, generate_gamma_table
+
+    init = gamma_table_initializer(2.8)
+    lut = ", ".join(f"0x{int(v):04X}" for v in generate_gamma_table(2.8))
+    assert init == f"{{{{{lut}}}, 280}}"
+
+
+def test_gamma_table_initializer_saturates_gamma_that_overflows_uint16() -> None:
+    from esphome.components.light import gamma_table_initializer
+
+    assert gamma_table_initializer(1000.0).endswith(", 65535}")