初始化 ToolBox 开发者工具箱。

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/unit/useLineNumberEditor.test.js

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+import { describe, it, expect } from 'vitest'
+import { countLines } from '../../src/composables/useLineNumberEditor.js'
+
+describe('useLineNumberEditor.countLines', () => {
+  it('returns 1 for empty or whitespace-only text', () => {
+    expect(countLines('')).toBe(1)
+    expect(countLines(null)).toBe(1)
+    expect(countLines(undefined)).toBe(1)
+  })
+
+  it('counts single line without trailing newline', () => {
+    expect(countLines('hello')).toBe(1)
+  })
+
+  it('counts multiple lines', () => {
+    expect(countLines('a\nb\nc')).toBe(3)
+    expect(countLines('a\nb\n')).toBe(3)
+  })
+})