[英]How to write unit test for javascript revealing module pattern with Jest?
For example: my math_util.js is例如:我的 math_util.js 是
var MathUtil = function(){
function add(a,b){
return a + b;
}
return {
add: add
};
}
I'll use Jest to test add().我将使用 Jest 来测试 add()。 So I'll write所以我会写
test('add', ()=>{
expect(MathUtil().add(1,1)).toBe(2);
});
But I get MathUtil
is undefined or MathUtil()
is not a function.但我得到MathUtil
未定义或MathUtil()
不是函数。
I also tried to use require()
or import
.我也尝试使用require()
或import
。 But MathUtil
doesn't have module.export
or export
.但是MathUtil
没有module.export
或export
。
So how to write unit test for javascript revealing module pattern with Jest?那么如何使用 Jest 为 javascript 揭示模块模式编写单元测试?
Note: I've a project with all scripts written in revealing module pattern so convert all to ES2015 module may not be practical.注意:我有一个项目,所有脚本都以揭示模块模式编写,因此将所有脚本都转换为 ES2015 模块可能不切实际。
If you really want to test math_util.js
exactly as it is written you can do this:如果您真的想完全按照编写的方式测试math_util.js
,您可以这样做:
// ---- math_util.test.js ----
const fs = require('fs');
const path = require('path');
const vm = require('vm');
const code = fs.readFileSync(path.join(__dirname, '/math_util.js'), 'utf-8');
const MathUtil = vm.runInThisContext(code + '; MathUtil');
test('add', ()=>{
expect(MathUtil().add(1,1)).toBe(2);
});
...but best practice would be to refactor the code into modules. ...但最佳实践是将代码重构为模块。 For the revealing module pattern that should be a very straightforward process, just remove the outer wrapping function and returned object, and put export
in front of anything that was in the returned object:对于应该是一个非常简单的过程的揭示模块模式,只需删除外部包装函数和返回对象,并将export
放在返回对象中的任何内容之前:
// ---- math_utils.js ----
export function add(a,b){
return a + b;
}
// ---- math_utils.test.js ----
import { add } from './math_utils';
test('add', ()=>{
expect(add(1,1)).toBe(2);
});
You can use babel-plugin-rewire
for this.您可以为此使用babel-plugin-rewire
。 Check this post: https://www.samanthaming.com/journal/2-testing-non-exported-functions/检查这篇文章: https : //www.samanthaming.com/journal/2-testing-non-exported-functions/
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