Vuex store.mutations is undefined in unit test

I have a simple store setup like this

src/store/index.js

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

export default new Vuex.Store({
  strict: true,
  state: {
    search: ''
  },
  mutations: {
    UPDATE_SEARCH(state, { query }) {
      state.search = query
    }
  }
})

However in my Unit Test, I include the store, but when I console.log the mutations property it returns undefined

import store from '@/store'

console.log(store.mutations)

When I console.log the store object, I can see _mutations property set, logging store.state is also working fine. Any idea why the mutations object isn't being read?

TypeError: Cannot read property 'UPDATE_SEARCH' of undefined