如何对独立Vue组成进行单元测试

时间:2020-01-28 21:50:04

标签: vue.js jestjs vue-test-utils vue-composition-api

我有一个类似于the example in the docs的设置,其中我的 composition 位于与我的组件不同的文件中,如下所示:

// composition.js
import { onMounted } from '@vue/composition-api';

export default function useComposition() {
  onMounted(() => {
    console.log('Hello, world!');
  });
}
// component.vue
<template>...</template>

<script>
import { createComponent } from '@vue/composition-api';

export default createComponent({
  setup() {
    useComposition();
  }
})
</script>

我只想为composition.js文件编写一个单独的(基于Jest的)测试文件。但是,直接调用合成时,Vue会出错(预期):

// composition.test.js

import useComposition from './composition';

describe('Composition', () => {
  it('Works', () => {
    useComposition();
    // Error: [vue-composition-api] "onMounted" get called outside of "setup()"
  });
});

为了提供setup()功能,我尝试安装基于模拟合成API的组件,但是在使其工作时遇到了一些麻烦:

import { mount, createLocalVue } from '@vue/test-utils';
import VueCompositionAPI, { createComponent } from '@vue/composition-api';
import useComposition from './composition';

const localVue = createLocalVue();
localVue.use(VueCompositionAPI);

describe('Composition', () => {
    it('Works', () => {
        const mockComponent = createComponent({
            setup() {
                useComposition();

                return h => h('div');
            }
        });

        mount(mockComponent, { localVue });
        // [Vue warn]: Failed to mount component: template or render function not defined.
    });
});

有人对如何使它起作用有什么聪明的主意,以便我可以为我的模块化作品编写测试吗?

1 个答案:

答案 0 :(得分:2)

错误[Vue warn]: Failed to mount component: template or render function not defined.是由于@vue/composition-api不支持在setup函数中返回渲染函数而导致的。有了这些知识,我就能创建一个有效的模拟组件渲染函数。以下内容似乎可以正常工作:

import VueCompositionAPI from '@vue/composition-api';
import { mount, createLocalVue } from '@vue/test-utils';

const localVue = createLocalVue();
localVue.use(VueCompositionAPI);

const mountComposition = (cb: () => any) => {
    return mount(
        {
            setup() {
                return cb();
            },
            render(h) {
                return h('div');
            }
        },
        { localVue }
    );
};

describe('My Test', () => {
    it('Works', () => {
        let value;

        const component = mountComposition(() => {
            value = useComposition();
        });

        expect(value).toBe(true);
    });
});