tests/test_mixer.py

import wave
from pathlib import Path

import numpy as np

from midnight_static.mixer import SAMPLE_RATE, mix_crude_broadcast, write_mono_wav


def test_crude_mixer_writes_louder_longer_output(tmp_path: Path):
    dialogue_path = tmp_path / "dialogue.wav"
    output_path = tmp_path / "mix.wav"
    seconds = np.arange(SAMPLE_RATE, dtype=np.float32) / SAMPLE_RATE
    dialogue = np.sin(2 * np.pi * 330 * seconds).astype(np.float32) * 0.2
    write_mono_wav(dialogue_path, dialogue)

    mix_crude_broadcast(dialogue_path, output_path)

    assert output_path.exists()
    with wave.open(str(output_path), "rb") as wav_file:
        assert wav_file.getnchannels() == 1
        assert wav_file.getframerate() == SAMPLE_RATE
        assert wav_file.getnframes() > SAMPLE_RATE