diff --git a/src/vanilla/utils/atomFamily.gru.test.ts b/src/vanilla/utils/atomFamily.gru.test.ts
new file mode 100644
index 0000000000..75f6768463
--- /dev/null
+++ b/src/vanilla/utils/atomFamily.gru.test.ts
@@ -0,0 +1,61 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/* eslint-disable @typescript-eslint/no-unused-vars */
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/* eslint-disable @typescript-eslint/no-unused-vars */
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { type Atom } from '../../vanilla.ts'
+import { atomFamily } from './atomFamily.ts'
+
+describe('atomFamily', () => {
+  let mockAtom: Atom<unknown>
+
+  beforeEach(() => {
+    mockAtom = { read: vi.fn(), write: vi.fn() } as any
+  })
+
+  it('should create an atom', () => {
+    const family = atomFamily(() => mockAtom)
+    const atom = family('param1')
+    expect(atom).toBe(mockAtom)
+  })
+
+  it('should return the same atom for the same parameter', () => {
+    const family = atomFamily(() => mockAtom)
+    const atom1 = family('param1')
+    const atom2 = family('param1')
+    expect(atom1).toBe(atom2)
+  })
+
+  it('should remove an atom', () => {
+    const family = atomFamily(() => mockAtom)
+    family('param1')
+    family.remove('param1')
+    const atom = family('param1')
+    expect(atom).toBe(mockAtom)
+  })
+
+  it('should notify listeners on atom creation', () => {
+    const family = atomFamily(() => mockAtom)
+    const listener = vi.fn()
+    family.unstable_listen(listener)
+    family('param1')
+    expect(listener).toHaveBeenCalledWith({
+      type: 'CREATE',
+      param: 'param1',
+      atom: mockAtom,
+    })
+  })
+
+  it('should notify listeners on atom removal', () => {
+    const family = atomFamily(() => mockAtom)
+    const listener = vi.fn()
+    family.unstable_listen(listener)
+    family('param1')
+    family.remove('param1')
+    expect(listener).toHaveBeenCalledWith({
+      type: 'REMOVE',
+      param: 'param1',
+      atom: mockAtom,
+    })
+  })
+})