diff --git a/packages/oxc-unshadowed-visitor/src/bindingNames.test.ts b/packages/oxc-unshadowed-visitor/src/bindingNames.test.ts
new file mode 100644
index 0000000..2130b56
--- /dev/null
+++ b/packages/oxc-unshadowed-visitor/src/bindingNames.test.ts
@@ -0,0 +1,79 @@
+import { describe, test, expect } from 'vitest'
+import { parseSync, type ESTree } from 'rolldown/utils'
+import { extractBindingNames } from './bindingNames.ts'
+
+function parse(code: string) {
+  return parseSync('test.js', code).program
+}
+
+describe('extractBindingNames', () => {
+  function extractFromParam(code: string): string[] {
+    const program = parse(`function f(${code}) {}`)
+    // oxlint-disable-next-line typescript/no-unsafe-type-assertion
+    const fn = program.body[0] as ESTree.Function
+    const names: string[] = []
+    for (const param of fn.params) {
+      extractBindingNames(param, names)
+    }
+    return names
+  }
+
+  function extractFromDecl(code: string): string[] {
+    const program = parse(code)
+    // oxlint-disable-next-line typescript/no-unsafe-type-assertion
+    const decl = program.body[0] as ESTree.VariableDeclaration
+    const names: string[] = []
+    for (const declarator of decl.declarations) {
+      extractBindingNames(declarator.id, names)
+    }
+    return names
+  }
+
+  test('simple identifier', () => {
+    expect(extractFromParam('a')).toEqual(['a'])
+  })
+
+  test('multiple params', () => {
+    expect(extractFromParam('a, b, c')).toEqual(['a', 'b', 'c'])
+  })
+
+  test('rest param', () => {
+    expect(extractFromParam('a, ...rest')).toEqual(['a', 'rest'])
+  })
+
+  test('array destructuring', () => {
+    expect(extractFromDecl('const [a, b] = arr')).toEqual(['a', 'b'])
+  })
+
+  test('array destructuring with holes', () => {
+    expect(extractFromDecl('const [a, , b] = arr')).toEqual(['a', 'b'])
+  })
+
+  test('object destructuring', () => {
+    expect(extractFromDecl('const { a, b } = obj')).toEqual(['a', 'b'])
+  })
+
+  test('renamed object destructuring', () => {
+    expect(extractFromDecl('const { x: a, y: b } = obj')).toEqual(['a', 'b'])
+  })
+
+  test('rest element in array', () => {
+    expect(extractFromDecl('const [a, ...rest] = arr')).toEqual(['a', 'rest'])
+  })
+
+  test('rest element in object', () => {
+    expect(extractFromDecl('const { a, ...rest } = obj')).toEqual(['a', 'rest'])
+  })
+
+  test('assignment pattern', () => {
+    expect(extractFromParam('a = 1, b = 2')).toEqual(['a', 'b'])
+  })
+
+  test('nested destructuring', () => {
+    expect(extractFromDecl('const { a: { b, c }, d } = obj')).toEqual(['b', 'c', 'd'])
+  })
+
+  test('deeply nested mixed destructuring', () => {
+    expect(extractFromDecl('const { a: [b, { c: d }], ...e } = obj')).toEqual(['b', 'd', 'e'])
+  })
+})
diff --git a/packages/oxc-unshadowed-visitor/src/mergeVisitors.test.ts b/packages/oxc-unshadowed-visitor/src/mergeVisitors.test.ts
new file mode 100644
index 0000000..e37c595
--- /dev/null
+++ b/packages/oxc-unshadowed-visitor/src/mergeVisitors.test.ts
@@ -0,0 +1,107 @@
+// oxlint-disable unicorn/consistent-function-scoping
+import { describe, test, expect } from 'vitest'
+import { mergeVisitors } from './mergeVisitors.ts'
+import type { VisitorContext } from './types.ts'
+import type { ESTree } from 'rolldown/utils'
+
+describe('mergeVisitors', () => {
+  const dummyIdentifierNode: ESTree.IdentifierReference = {
+    type: 'Identifier',
+    name: 'foo',
+    start: 0,
+    end: 3,
+  }
+  function makeCtx(): VisitorContext<string> {
+    return {
+      record() {},
+    }
+  }
+
+  test('user enter runs after internal enter', () => {
+    const order: string[] = []
+    const merged = mergeVisitors(
+      {
+        Identifier: () => order.push('user-enter'),
+      },
+      makeCtx(),
+      { Identifier: () => order.push('internal-enter') },
+      {},
+    )
+    merged.Identifier(dummyIdentifierNode)
+    expect(order).toEqual(['internal-enter', 'user-enter'])
+  })
+
+  test('user exit runs before internal exit', () => {
+    const order: string[] = []
+    const merged = mergeVisitors(
+      {
+        'Identifier:exit': () => order.push('user-exit'),
+      },
+      makeCtx(),
+      {},
+      { 'Identifier:exit': () => order.push('internal-exit') },
+    )
+    merged['Identifier:exit'](dummyIdentifierNode)
+    expect(order).toEqual(['user-exit', 'internal-exit'])
+  })
+
+  test('internal-only visitors are included', () => {
+    const ctx = makeCtx()
+    const enterFn = () => {}
+    const exitFn = () => {}
+    const merged = mergeVisitors({}, ctx, { Identifier: enterFn }, { 'Identifier:exit': exitFn })
+    expect(merged.Identifier).toBe(enterFn)
+    expect(merged['Identifier:exit']).toBe(exitFn)
+  })
+
+  test('user-only visitors are included', () => {
+    const called: string[] = []
+    const ctx = makeCtx()
+    const merged = mergeVisitors(
+      {
+        Identifier: () => called.push('identifier'),
+        'Identifier:exit': () => called.push('identifier-exit'),
+      },
+      ctx,
+      {},
+      {},
+    )
+    merged.Identifier(dummyIdentifierNode)
+    merged['Identifier:exit'](dummyIdentifierNode)
+    expect(called).toEqual(['identifier', 'identifier-exit'])
+  })
+
+  test('ctx is passed to user visitor functions', () => {
+    let receivedCtx: unknown
+    const ctx = makeCtx()
+    const merged = mergeVisitors(
+      {
+        Identifier: (_node, c) => {
+          receivedCtx = c
+        },
+      },
+      ctx,
+      {},
+      {},
+    )
+    merged.Identifier(dummyIdentifierNode)
+    expect(receivedCtx).toBe(ctx)
+  })
+
+  test('ctx is passed to user exit visitor functions', () => {
+    let receivedCtx: unknown
+    const ctx = makeCtx()
+    const merged = mergeVisitors(
+      {
+        'Identifier:exit': (_node, c) => {
+          receivedCtx = c
+        },
+      },
+      ctx,
+      {},
+      {},
+    )
+    merged['Identifier:exit'](dummyIdentifierNode)
+    expect(receivedCtx).toBe(ctx)
+  })
+})