fix: drum single hit, dedupe notes, validate role

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

tests/score/roundtrip.test.ts

@@ -80,3 +80,34 @@ test("GP round trip preserves notes, ties, strings, roles", () => {
 test("songToMidi generates events", () => {
   expect(songToMidi(song).tracks.length).toBeGreaterThan(0);
 });
+
+function drumSong(notes: { tick: number; dur: number; pitch: number }[]): Song {
+  return {
+    title: "d", tier: "t1", seed: 1, bpm: BPM, timeSig: [4, 4], bars: 2, key: "C",
+    tracks: [{ name: "Kit", role: "drums", program: 0, pan: 0, fx: "none", gainDb: 0, notes }],
+  };
+}
+
+test("drum note with multi-piece duration yields exactly one hit", () => {
+  const truth = truthFromGp(songToGp(drumSong([{ tick: 0, dur: 5 * S, pitch: 38 }])));
+  expect(truth.tracks[0]!.notes.map((n) => [n.pitch, n.onset])).toEqual([[38, 0]]);
+});
+
+test("drum note crossing a barline yields exactly one hit", () => {
+  const truth = truthFromGp(songToGp(drumSong([{ tick: 3 * Q, dur: 2 * Q, pitch: 36 }])));
+  expect(truth.tracks[0]!.notes.map((n) => [n.pitch, round3(n.onset)])).toEqual([[36, round3(t(3 * Q))]]);
+});
+
+test("exact duplicate notes are de-duplicated", () => {
+  const dup = { tick: Q, dur: Q, pitch: 60 };
+  const s = drumSong([]);
+  s.tracks = [{ name: "V", role: "vocals", program: 53, pan: 0, fx: "none", gainDb: 0, notes: [dup, { ...dup }] }];
+  const truth = truthFromGp(songToGp(s));
+  expect(truth.tracks[0]!.notes.length).toBe(1);
+});
+
+test("truthFromGp rejects an invalid role short name", () => {
+  const s = drumSong([{ tick: 0, dur: Q, pitch: 36 }]);
+  (s.tracks[0] as any).role = "banjo";
+  expect(() => truthFromGp(songToGp(s))).toThrow(/not a valid Role/);
+});