Merge pull request #74 from MurineShiftWork/fix/sounds-ttl-channel-zero

fix(sounds): keep a valid ttl_channel=0 instead of clobbering to default

Author: larsrollik

src/murineshiftwork/logic/sounds.py

@@ -81,7 +81,7 @@ def __init__(
         self,
         sound_device: str | None = None,
         sample_rate: int | None = None,
-        ttl_channel: int = 1,
+        ttl_channel: int | None = None,
         ttl_duration: float = 0.001,
         channel_mode: str | None = None,
         allow_sys_default_device=True,
@@ -203,7 +203,10 @@ def __init__(
                 self.sample_rate = _fallback_sr
                 self.use_wasapi_exclusive = False
 
-        self.ttl_channel = ttl_channel or self.default_ttl_channel
+        # `or` would clobber a valid ttl_channel=0 to the default; select on None instead.
+        self.ttl_channel = (
+            self.default_ttl_channel if ttl_channel is None else ttl_channel
+        )
         if self.ttl_channel != 0 and self.ttl_channel != 1:
             raise ValueError(
                 f"'ttl_channel' has to be 0 or 1 for stereo output, but '{self.ttl_channel}' given"

tests/test_sounds.py

@@ -125,6 +125,23 @@ def test_default_output_fallback_not_sysdefault(monkeypatch):
     assert s.sample_rate == 48000
 
 
+def test_ttl_channel_zero_is_not_clobbered_to_default(monkeypatch):
+    """ttl_channel=0 is a valid channel index; it must survive __init__ (was lost to `or default`)."""
+    import sys
+    import types
+
+    dev = {"name": "X", "default_samplerate": 48000.0}
+    fake_sd = types.SimpleNamespace(check_output_settings=lambda **kw: None)
+    monkeypatch.setitem(sys.modules, "sounddevice", fake_sd)
+    monkeypatch.setattr(
+        "murineshiftwork.logic.sounds.find_sound_device", lambda **kw: (5, dev)
+    )
+
+    assert StereoSound(sound_device="X", ttl_channel=0).ttl_channel == 0
+    # omitted -> falls back to the class default
+    assert StereoSound(sound_device="X").ttl_channel == StereoSound.default_ttl_channel
+
+
 def test_falls_back_to_default_rate_when_device_rejects(monkeypatch):
     """Device found but rejecting the configured rate (e.g. XONAR 192000 when its
     driver/Windows format is not at 192000): fall back to the device default so