Music21 Composer MCP

"""Tests for export_midi tool.""" import base64 import pytest from music21 import midi from composer_mcp.core.models import ExportMidiRequest, InputFormat from composer_mcp.core.service import CompositionService @pytest.fixture def service(): """Create a composition service instance.""" return CompositionService() class TestExportMidi: """Tests for export_midi functionality.""" def test_export_simple_notes(self, service): """Export simple note list to MIDI.""" request = ExportMidiRequest( stream="C4, D4, E4, G4", tempo=120, ) response = service.export_midi(request) assert response.success is True assert response.error is None assert response.data is not None # Check MIDI data midi_data = response.data["midi"] assert "base64" in midi_data assert midi_data["tempo"] == 120 assert midi_data["duration_seconds"] > 0 # Verify base64 is valid MIDI midi_bytes = base64.b64decode(midi_data["base64"]) assert midi_bytes[:4] == b"MThd" # MIDI header def test_export_with_durations(self, service): """Export notes with explicit durations.""" request = ExportMidiRequest( stream="C4:h, D4:q, E4:q", tempo=120, ) response = service.export_midi(request) assert response.success is True # Half (2) + quarter (1) + quarter (1) = 4 quarter lengths at 120 BPM = 2 seconds assert response.data["midi"]["duration_seconds"] == pytest.approx(2.0, rel=0.1) def test_export_with_different_tempo(self, service): """Tempo affects duration.""" request_slow = ExportMidiRequest(stream="C4:w", tempo=60) request_fast = ExportMidiRequest(stream="C4:w", tempo=120) response_slow = service.export_midi(request_slow) response_fast = service.export_midi(request_fast) # Same notes, different tempo = different duration slow_duration = response_slow.data["midi"]["duration_seconds"] fast_duration = response_fast.data["midi"]["duration_seconds"] assert slow_duration == pytest.approx(fast_duration * 2, rel=0.1) def test_export_explicit_format(self, service): """Explicit input format.""" request = ExportMidiRequest( stream="C4 D4 E4", input_format=InputFormat.NOTES, tempo=120, ) response = service.export_midi(request) assert response.success is True def test_export_with_humanization(self, service): """Humanization modifies output.""" request_normal = ExportMidiRequest( stream="C4, D4, E4, G4", humanize=False, ) request_humanized = ExportMidiRequest( stream="C4, D4, E4, G4", humanize=True, humanize_amount=0.5, ) response_normal = service.export_midi(request_normal) response_humanized = service.export_midi(request_humanized) # Both should succeed assert response_normal.success is True assert response_humanized.success is True # MIDI output should be different (humanization adds variation) # Note: This might occasionally fail if randomization produces same result normal_midi = response_normal.data["midi"]["base64"] humanized_midi = response_humanized.data["midi"]["base64"] # Just verify both are valid MIDI, don't compare bytes assert base64.b64decode(normal_midi)[:4] == b"MThd" assert base64.b64decode(humanized_midi)[:4] == b"MThd" def test_export_metadata(self, service): """Response includes metadata.""" request = ExportMidiRequest( stream="C4, D4, E4, G4", tempo=100, ) response = service.export_midi(request) assert response.success is True metadata = response.data["metadata"] assert "note_count" in metadata assert metadata["note_count"] == 4 assert "time_signature" in metadata def test_export_include_abc(self, service): """Include ABC notation in response.""" request = ExportMidiRequest( stream="C4, D4, E4", include_abc=True, ) response = service.export_midi(request) assert response.success is True assert response.data.get("abc") is not None def test_export_empty_input_fails(self, service): """Empty input is caught by Pydantic validation.""" import pydantic with pytest.raises(pydantic.ValidationError): ExportMidiRequest(stream="") def test_export_invalid_notes_fails(self, service): """Invalid notes return error.""" request = ExportMidiRequest(stream="X9, Y8, Z7") response = service.export_midi(request) assert response.success is False assert response.error is not None def test_velocity_curves(self, service): """Different velocity curves produce valid output.""" for curve in ["flat", "dynamic", "crescendo", "diminuendo"]: request = ExportMidiRequest( stream="C4, D4, E4, G4, C5", humanize=True, velocity_curve=curve, ) response = service.export_midi(request) assert response.success is True, f"Failed for curve: {curve}" def test_api_version_included(self, service): """Response includes API version.""" request = ExportMidiRequest(stream="C4") response = service.export_midi(request) assert response.api_version == "0.1.0"