Testing components with Vue.js actions

I'm comfortable with Vue.js but tests have been a struggle for me. I always seem to run into problems when something involves Promises. Right now I'm testing a basic component that dispatches a Vue.js action.

Something like

<template>
  <div>
    <button @click="create"></button>
  </div>
</template>
<script>
export default {
  data() {
    return {
      someval: 0
    }
  },
  methods: {
    create() {
      this.$store.dispatch('create-event').then((res) => {
        this.someval  ;
      }).catch((err) => { logError(); });
    }
  }
}
</script>

And my test checks the interaction of the button, and that the correct response is called.

describe('Create stuff', () => {
  beforeEach(() => {
    // more testing setup stuff here
    actions = {
      'create-event': sinon.fake()
    };
    // store uses these actions
  });

  it('creates stuff when submitted', () => {
    const wrapper = shallowMount(CreateStuff, { store });
    const button = wrapper.find('button');
    button.vm.$emit('click');

    assert.isTrue(actions['create-event'].calledOnce); // passes
    assert.equal(wrapper.vm.someval, 1); // fails
  });
}

I'm following the vue-test-utils guidelines to mock my actions. I've tried using sinon.fake.resolves() to resolve the action with a Promise. I've tried wrapping things in nextTick. But no matter what I do the "this.someval " never gets called until after the test is over.

Should I be mocking the entire $store.dispatch? This was my initial instinct, but all the Vuex and testing guides seem to want me to mock the actions themselves.

What's the proper way to test components with vuex actions that return a promise?