Test Maintenance & Anti-Patterns

"""Replace hard-coded sleeps with robust wait helpers."""
import time
from typing import Callable, Optional

def wait_for_signal(
        read_fn: Callable[[], Optional[float]],
        expected_value,
        timeout_s: float = 5.0,
        poll_interval_s: float = 0.05,
        tolerance: float = 0.0) -> bool:
    """Poll signal until expected value or timeout."""
    deadline = time.monotonic() + timeout_s
    while time.monotonic() < deadline:
        value = read_fn()
        if value is not None:
            if tolerance == 0.0:
                if value == expected_value:
                    return True
            else:
                if abs(value - expected_value) <= tolerance:
                    return True
        time.sleep(poll_interval_s)
    return False

# BEFORE (fragile):
# ecu.send_signal("VehicleSpeed", 50.0)
# time.sleep(2.0)  # magic number -- may be too long or too short
# assert ecu.read_signal("AEB_State") == "ACTIVE"

# AFTER (robust):
# ecu.send_signal("VehicleSpeed", 50.0)
# ok = wait_for_signal(lambda: ecu.read_signal("AEB_State"),
#                      expected_value="ACTIVE", timeout_s=2.0)
# assert ok, "AEB did not activate within 2.0s"