vue-function-tester.js

// SomeComponent.vue
export default {
  props: {
    a: {
      type: Number
    }
  },
  date () {
    return {
      b: 1,
      liked: false
    }
  }
  ~~~~~~~~~~
  methods: {
    sayHi () {
      return 'Hi'
    }
    add (c) {
      return this.a + this.b + c
    },
    like () {
      this.liked = !this.liked
    },
    recommend () {
      if (this.liked) {
        this.notify()
      } else {
        alert('should like before recommend.')
      }
    }
  }
}


// Button.spec.js
import tester from 'vue-function-tester';
import SomeComponent from 'SomeComponent.vue';

describe('methods', () => {
  const { saiHi, add, like, recomend } = tester.methods(SomeComponent);
  
  describe('hello', () => {
    it('returns Hi', () => {
      // run() returns result object
      expect(saiHi().run().return).toBe('Hi')
    });
  });

  describe('add', () => {
    it('returns 6', () => {
      expect(add(3).run({ a: 1, b: 2 }).return).toBe(6)
    });
  });
  
  describe('like', () => {
    it('is true', () => {
      const result = like().run({ liked: false })
      expect(result.liked).toBe(true)
      expect(result.return).toBe(undefined)
    });
  });
  
  describe('recommend', () => {
    describe('liked = true', {
      it('calls notify', () => {
        const result = recommend().run({ liked: false });
        expect(result.notify.calls).toEqual([[]])
        expect(result.notify.called).toBe(true)
      });
    });
  });
});