vue-test-utils throws an error 'TypeError: inject is not a function'

I wrote a global plugin and used it in a component.

plugins/passwordValidation.js:

export default function ({ app }, inject) {
  inject('passwordValidation', (password, passwordForConfirming) => {
    const errors = []
    ...
    return errors
  })
}

...
<script>
...
export default { 
  ...
  watch: {
    password(newPassword, oldPassword) {
      this.passwordValidationWarnings = this.$passwordValidation(
        newPassword,
        this.passwordForConfirming
      )
    },
  ...
}
</script>

Then after writing a test with reference to the documentation, I noticed an following error occurred.

An error message:

 FAIL  test/components/organisms/RegisterForm.spec.js
  ● Test suite failed to run

    TypeError: inject is not a function

      1 | export default function ({ app }, inject) {
    > 2 |   inject('passwordValidation', (password, passwordForConfirming) => {
        |   ^
      3 |     const errors = []

test/components/organisms/RegisterForm.spec.js:

import { createLocalVue, shallowMount } from '@vue/test-utils'
import Vuex, { Store } from 'vuex'
import RegisterForm from '@/components/organisms/RegisterForm.vue'
import passwordValidation from '@/plugins/passwordValidation.js'

const localVue = createLocalVue()
localVue.use(Vuex)
localVue.use(passwordValidation)

describe('RegisterForm', () => {
  describe('When the registration succeeds', () => {
    beforeEach(() => {
      ...
      wrapper = shallowMount(RegisterForm, {
        localVue,
        ...
      })
    ...
    })

How can I fix this error to use the plugin in my test?

For reference, the versions of the applications used are as follows.

• nuxt: 2.15.8
• @vue/test-utils: 1.3.0
• jest: 27.5.1

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