feat: VSTi autosample -> SF2/SF3 (tools/autosample_vsti.py) + bit_depth 16/24/32 render/export WAV (render_engine, plugins API, audio_editor, app.jsx encoders) + tests + task/walkthrough docs (53)

tests/test_autosampler.py

@@ -0,0 +1,55 @@
+"""Tests cho tools/autosample_vsti.py — SF2 writer tự-sinh phải là RIFF/sfbk
+hợp lệ mà sf2utils parse được (không cần VSTi/pedalboard)."""
+import os
+import numpy as np
+import pytest
+
+from tools.autosample_vsti import write_sf2
+
+sf2utils = pytest.importorskip("sf2utils.sf2parse")
+
+
+def _sine(note, sr=44100, dur=0.2):
+    t = np.arange(int(sr * dur)) / sr
+    f = 440.0 * 2 ** ((note - 69) / 12)
+    return (np.sin(2 * np.pi * f * t) * 20000).astype(np.int16)
+
+
+def test_write_sf2_valid_structure(tmp_path):
+    out = str(tmp_path / "test.sf2")
+    samples = [{"note": n, "frames": _sine(n)} for n in (60, 62, 64)]
+    write_sf2(out, samples, sample_rate=44100, name="Test")
+    assert os.path.getsize(out) > 100
+    with open(out, "rb") as f:
+        head = f.read(12)
+    assert head[:4] == b"RIFF"
+    assert head[8:12] == b"sfbk"
+    with open(out, "rb") as f:
+        sf2 = sf2utils.Sf2File(f)
+    real_samples = [s for s in sf2.samples if s.end > s.start]
+    assert len(real_samples) == 3
+    assert len(sf2.presets) == 2  # preset + terminator
+    assert sf2.presets[0].bank == 0
+    assert sf2.presets[0].preset == 0
+    assert sf2.presets[0].name == "Test"
+    for s in real_samples:
+        assert s.end - s.start == 8820
+        assert s.sample_rate == 44100
+
+
+def test_write_sf2_rejects_empty(tmp_path):
+    with pytest.raises(ValueError):
+        write_sf2(str(tmp_path / "empty.sf2"), [])
+
+
+def test_write_sf2_odd_name_no_corruption(tmp_path, caplog):
+    """INFO text chunk chan — ten le (vd "Nexus") khong duoc lam mat can
+    (sf2utils khong skip pad byte cua odd-size chunk)."""
+    import logging
+    out = str(tmp_path / "odd.sf2")
+    write_sf2(out, [{"note": 60, "frames": _sine(60)}], 44100, name="Nexus")
+    with caplog.at_level(logging.WARNING):
+        with open(out, "rb") as f:
+            sf2 = sf2utils.Sf2File(f)
+    assert len([s for s in sf2.samples if s.end > s.start]) == 1
+    assert not any("corrupted" in r.message for r in caplog.records)