Implement comprehensive tests for pattern event parsing and normalization.

tests/pattern-events.test.ts

@@ -0,0 +1,101 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { parsePatternEvents } from '../src/lib/parsers';
+
+function buildPattern(records: number[][], bars: number = 4, declaredCount = records.length) {
+  const data = new Uint8Array(4 + records.length * 8);
+  data[1] = bars;
+  data[2] = declaredCount & 0xff;
+  data[3] = declaredCount >> 8;
+
+  records.forEach((record, index) => {
+    data.set(record, 4 + index * 8);
+  });
+
+  return data;
+}
+
+test('parses note records without changing the derived note shape', () => {
+  const result = parsePatternEvents(buildPattern([[0x34, 0x12, 3 << 3, 64, 99, 0x78, 0x56, 7]]));
+
+  assert.equal(result.bars, 4);
+  assert.equal(result.recordCount, 1);
+  assert.deepEqual(result.notes, {
+    3: [{ note: 64, position: 0x1234, duration: 0x5678, velocity: 99 }],
+  });
+  assert.deepEqual(result.events[0], {
+    type: 'note',
+    kind: 0,
+    position: 0x1234,
+    source: 3,
+    flags: 7,
+    rawData: new Uint8Array([0x34, 0x12, 3 << 3, 64, 99, 0x78, 0x56, 7]),
+    pad: 3,
+    note: 64,
+    velocity: 99,
+    duration: 0x5678,
+  });
+});
+
+test('parses and normalizes fader records', () => {
+  const result = parsePatternEvents(buildPattern([[0x60, 0, 1, 7, 9, 0xff, 0x7f, 128]]));
+
+  assert.deepEqual(result.notes, {});
+  assert.deepEqual(result.events[0], {
+    type: 'fader',
+    kind: 1,
+    position: 96,
+    source: 0,
+    flags: 128,
+    rawData: new Uint8Array([0x60, 0, 1, 7, 9, 0xff, 0x7f, 128]),
+    parameter: 7,
+    reserved: 9,
+    rawValue: 32767,
+    value: 1,
+  });
+});
+
+test('preserves MIDI and unknown records', () => {
+  const midi = [1, 0, (4 << 3) | 2, 0xd0, 75, 3, 4, 5];
+  const unknown = [2, 0, (5 << 3) | 6, 10, 11, 12, 13, 14];
+  const result = parsePatternEvents(buildPattern([midi, unknown]));
+
+  assert.deepEqual(result.events[0], {
+    type: 'midi',
+    kind: 2,
+    position: 1,
+    source: 4,
+    flags: 5,
+    rawData: new Uint8Array(midi),
+    data: new Uint8Array([0xd0, 75, 3, 4]),
+  });
+  assert.deepEqual(result.events[1], {
+    type: 'unknown',
+    kind: 6,
+    position: 2,
+    source: 5,
+    flags: 14,
+    rawData: new Uint8Array(unknown),
+    data: new Uint8Array([10, 11, 12, 13]),
+  });
+});
+
+test('uses the uint16 header count and ignores undeclared or partial records', () => {
+  const records = Array.from({ length: 300 }, (_, index) => [
+    index & 0xff,
+    index >> 8,
+    0,
+    60,
+    100,
+    1,
+    0,
+    0,
+  ]);
+  const data = buildPattern([...records, [0, 0, 1, 0, 0, 0, 0, 0]], 8, 300);
+  const truncated = data.slice(0, data.length - 3);
+  const result = parsePatternEvents(truncated);
+
+  assert.equal(result.recordCount, 300);
+  assert.equal(result.events.length, 300);
+  assert.equal(result.events[299].position, 299);
+});