test(led-driver): add pattern smoke harness

Made-with: Cursor

tests/fake_driver.py

@@ -0,0 +1,43 @@
+"""Minimal Presets-like stub for pattern smoke tests (no machine / NeoPixel)."""
+
+
+class _FakeNeo:
+    def __init__(self, count):
+        self._count = count
+        self.pixels = [(0, 0, 0)] * count
+
+    def fill(self, color):
+        self.pixels = [tuple(color) for _ in range(self._count)]
+
+    def __setitem__(self, index, value):
+        self.pixels[index] = tuple(value)
+
+    def __getitem__(self, index):
+        return self.pixels[index]
+
+    def write(self):
+        pass
+
+
+class FakePresets:
+    """Subset of led-driver Presets API used by patterns/*.py."""
+
+    def __init__(self, num_leds=24):
+        self.num_leds = num_leds
+        self.n = _FakeNeo(num_leds)
+        self.b = 255
+        self.step = 0
+
+    def apply_brightness(self, color, brightness_override=None):
+        local = brightness_override if brightness_override is not None else 255
+        effective_brightness = int(local * self.b / 255)
+        return tuple(int(c * effective_brightness / 255) for c in color)
+
+    def fill(self, color=None):
+        fill_color = color if color is not None else (0, 0, 0)
+        for i in range(self.num_leds):
+            self.n[i] = fill_color
+        self.n.write()
+
+    def off(self):
+        self.fill((0, 0, 0))