Another try for lag.

tests/unit/test_dectalk_usb_driver.py

@@ -107,7 +107,7 @@ def build_environment():
     }
 
 
-def initialized_driver(monkeypatch):
+def initialized_driver(monkeypatch, clear_startup_writes=True):
     device = FakeUsbDevice()
     usb_core = FakeUsbCore(device)
     usb_util = FakeUsbUtil()
@@ -118,6 +118,8 @@ def initialized_driver(monkeypatch):
         lambda: (usb_core, usb_util),
     )
     speech_driver.initialize(build_environment())
+    if clear_startup_writes:
+        device.writes.clear()
     return speech_driver, device, usb_core, usb_util
 
 
@@ -142,6 +144,17 @@ def test_dectalk_usb_driver_finds_and_claims_native_device(monkeypatch):
     assert usb_util.disposed == [device]
 
 
+def test_dectalk_usb_driver_sets_low_buffer_timeout_on_initialize(monkeypatch):
+    speech_driver, device, _, _ = initialized_driver(
+        monkeypatch,
+        clear_startup_writes=False,
+    )
+    try:
+        assert device.writes[0] == (0x02, b"[:timeout 1]", 1000)
+    finally:
+        speech_driver.shutdown()
+
+
 def test_dectalk_usb_driver_writes_commands_and_speech(monkeypatch):
     speech_driver, device, _, _ = initialized_driver(monkeypatch)
     try:
@@ -212,6 +225,7 @@ def test_dectalk_usb_cancel_bypasses_blocked_normal_write(monkeypatch):
         lambda: (usb_core, usb_util),
     )
     speech_driver.initialize(build_environment())
+    device.writes.clear()
     normal_thread = threading.Thread(
         target=speech_driver._write_bytes,
         args=(b"normal speech", "speech"),
@@ -240,6 +254,8 @@ def test_dectalk_usb_cancel_stops_current_speech_upload(monkeypatch):
         lambda: (usb_core, usb_util),
     )
     speech_driver.initialize(build_environment())
+    device.writes.clear()
+    device.first_normal_write_started.clear()
     normal_thread = threading.Thread(
         target=speech_driver._write_bytes,
         args=(b"x" * 192, "speech"),