feat: add Vitest unit testing infrastructure with initial test suite.

src/core/midi/KGMidiNote.test.ts

@@ -0,0 +1,151 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import { KGMidiNote } from './KGMidiNote'
+
+describe('KGMidiNote', () => {
+  let note: KGMidiNote
+
+  beforeEach(() => {
+    note = new KGMidiNote('test-note', 0, 1, 60, 80)
+  })
+
+  describe('constructor', () => {
+    it('should create a note with correct properties', () => {
+      const testNote = new KGMidiNote('note-1', 2, 4, 72, 100)
+      
+      expect(testNote.getId()).toBe('note-1')
+      expect(testNote.getStartBeat()).toBe(2)
+      expect(testNote.getEndBeat()).toBe(4)
+      expect(testNote.getPitch()).toBe(72)
+      expect(testNote.getVelocity()).toBe(100)
+    })
+
+    it('should use default values when not provided', () => {
+      const defaultNote = new KGMidiNote('default-note')
+      
+      expect(defaultNote.getId()).toBe('default-note')
+      expect(defaultNote.getStartBeat()).toBe(0)
+      expect(defaultNote.getEndBeat()).toBe(0)
+      expect(defaultNote.getPitch()).toBe(0)
+      expect(defaultNote.getVelocity()).toBe(127)
+    })
+  })
+
+  describe('getters and setters', () => {
+    it('should get and set start beat', () => {
+      expect(note.getStartBeat()).toBe(0)
+      
+      note.setStartBeat(1.5)
+      expect(note.getStartBeat()).toBe(1.5)
+    })
+
+    it('should get and set end beat', () => {
+      expect(note.getEndBeat()).toBe(1)
+      
+      note.setEndBeat(3.5)
+      expect(note.getEndBeat()).toBe(3.5)
+    })
+
+    it('should get and set pitch', () => {
+      expect(note.getPitch()).toBe(60)
+      
+      note.setPitch(72)
+      expect(note.getPitch()).toBe(72)
+    })
+
+    it('should get and set velocity', () => {
+      expect(note.getVelocity()).toBe(80)
+      
+      note.setVelocity(100)
+      expect(note.getVelocity()).toBe(100)
+    })
+
+    it('should get and set ID', () => {
+      expect(note.getId()).toBe('test-note')
+      
+      note.setId('new-id')
+      expect(note.getId()).toBe('new-id')
+    })
+  })
+
+  describe('selection', () => {
+    it('should start unselected', () => {
+      expect(note.isSelected()).toBe(false)
+    })
+
+    it('should select and deselect', () => {
+      note.select()
+      expect(note.isSelected()).toBe(true)
+      
+      note.deselect()
+      expect(note.isSelected()).toBe(false)
+    })
+  })
+
+  describe('note duration', () => {
+    it('should calculate duration correctly', () => {
+      const durationNote = new KGMidiNote('duration-test', 1, 3, 60, 80)
+      expect(durationNote.getEndBeat() - durationNote.getStartBeat()).toBe(2)
+    })
+
+    it('should handle zero duration', () => {
+      const zeroDurationNote = new KGMidiNote('zero-duration', 2, 2, 60, 80)
+      expect(zeroDurationNote.getEndBeat() - zeroDurationNote.getStartBeat()).toBe(0)
+    })
+  })
+
+  describe('pitch validation', () => {
+    it('should accept valid MIDI pitch range', () => {
+      // MIDI pitch range is typically 0-127
+      note.setPitch(0)
+      expect(note.getPitch()).toBe(0)
+      
+      note.setPitch(127)
+      expect(note.getPitch()).toBe(127)
+      
+      note.setPitch(60) // Middle C
+      expect(note.getPitch()).toBe(60)
+    })
+  })
+
+  describe('velocity validation', () => {
+    it('should accept valid MIDI velocity range', () => {
+      // MIDI velocity range is typically 0-127
+      note.setVelocity(0)
+      expect(note.getVelocity()).toBe(0)
+      
+      note.setVelocity(127)
+      expect(note.getVelocity()).toBe(127)
+      
+      note.setVelocity(64) // Mid velocity
+      expect(note.getVelocity()).toBe(64)
+    })
+  })
+
+  describe('clone and comparison', () => {
+    it('should create independent instances', () => {
+      const note1 = new KGMidiNote('note-1', 0, 1, 60, 80)
+      const note2 = new KGMidiNote('note-2', 0, 1, 60, 80)
+      
+      expect(note1.getId()).not.toBe(note2.getId())
+      
+      note1.setPitch(72)
+      expect(note2.getPitch()).toBe(60) // Should remain unchanged
+    })
+  })
+
+  describe('edge cases', () => {
+    it('should handle negative start beat', () => {
+      note.setStartBeat(-1)
+      expect(note.getStartBeat()).toBe(-1)
+    })
+
+    it('should handle start beat after end beat', () => {
+      note.setStartBeat(5)
+      note.setEndBeat(2)
+      
+      expect(note.getStartBeat()).toBe(5)
+      expect(note.getEndBeat()).toBe(2)
+      // Note: The class might need validation logic to prevent this
+    })
+  })
+})