test_tap_engine.py

import unittest

import numpy as np

from tap_engine import (
    IGNORE_LABEL,
    TapClassifier,
    TapListener,
    candidate_quality,
    extract_features,
    feature_size,
)


def synthetic_tap(channel: int = 0) -> np.ndarray:
    rate = 44_100
    audio = np.zeros((int(rate * 0.32), 4), dtype=np.float32)
    start = 650
    length = 1800
    t = np.arange(length) / rate
    ring = np.sin(2 * np.pi * (800 + channel * 550) * t) * np.exp(-t * 70)
    for index in range(4):
        delay = abs(index - channel) * 3
        scale = 1.0 if index == channel else 0.35
        audio[start + delay : start + delay + length, index] = ring * scale
    return audio


class TapEngineTests(unittest.TestCase):
    def test_multichannel_features_are_fixed_and_finite(self):
        feature = extract_features(synthetic_tap())
        self.assertEqual(feature.shape, (feature_size(),))
        self.assertTrue(np.all(np.isfinite(feature)))

    def test_array_features_change_with_tap_side(self):
        left = extract_features(synthetic_tap(0))
        right = extract_features(synthetic_tap(3))
        self.assertGreater(float(np.linalg.norm(left - right)), 0.1)

    def test_short_decaying_impact_has_quality(self):
        quality, metrics = candidate_quality(synthetic_tap())
        self.assertGreater(quality, 0.35)
        self.assertLess(metrics["duration_ms"], 200)

    def test_classifier_selects_zone_and_ignore_class(self):
        rng = np.random.default_rng(7)
        left = extract_features(synthetic_tap(0))
        right = extract_features(synthetic_tap(3))
        ignored = np.ones(feature_size(), dtype=np.float32) * 0.45
        samples = {
            "left": [(left + rng.normal(0, 0.002, feature_size())).tolist() for _ in range(8)],
            "right": [(right + rng.normal(0, 0.002, feature_size())).tolist() for _ in range(8)],
            IGNORE_LABEL: [(ignored + rng.normal(0, 0.002, feature_size())).tolist() for _ in range(8)],
        }
        model = TapClassifier(samples)
        self.assertEqual(model.predict(right).zone_id, "right")
        self.assertEqual(model.predict(ignored).zone_id, IGNORE_LABEL)

    def test_listener_clamps_sensitivity(self):
        self.assertEqual(TapListener(lambda *_: None, sensitivity=99).sensitivity, 10)
        self.assertEqual(TapListener(lambda *_: None, sensitivity=-1).sensitivity, 1)


if __name__ == "__main__":
    unittest.main()