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如何使用sinon并重新接线来模拟另一个文件中定义的常量?
我是JS测试的初学者,当我尝试在需要测试的文件中模拟常量值时遇到问题。
我有以下文件
// index.js
const { MultiAccounts } = require('../../some.js')
const MultiAccountInstance = new MultiAccounts();
...
const syncEvents = () => Promise.try(() => {
// ...
return MultiAccountInstance.all()
.then((accounts) => // ...); // ==> it throws the exception here Cannot read property 'then' of undefined
});
module.exports = syncEvents;
所以,我想模拟MultiAccountInstance
常量。我一直在尝试使用Simon和rewire,但是使用以下脚本,我已经它在这里引发了异常无法读取上面脚本中的属性'then'of undefined异常。
//index.test.js
const rewire = require('rewire');
const indexRewired = rewire('.../../index/js');
describe('testing sync events', () => {
let fakeMultiAccountInstance, MultiAccountInstanceReverter;
let accounts;
beforeEach(() => {
accounts = [{id: 1}, {id: 2}];
fakeMultiAccountInstance = {};
fakeMultiAccountInstance.all = () => Promise.resolve(accounts);
MultiAccountInstanceReverter = indexRewired.__set__('MultiAccountInstance', fakeMultiAccountInstance);
});
afterEach(() => {
MultiAccountInstanceReverter();
});
it('testing', ()=> {
const spy = sinon.stub(fakeMultiAccountInstance, 'all');
return indexRewired().then((resp) => {
spy.restore();
expect(spy).to.have.been.calledWith({someParams: true});
});
})
});
我该如何实现?我也尝试使用存根,但是出现了错误,即MultiAccountInstance.all不是一个函数
有点像这样
//index.test.js
const rewire = require('rewire');
const indexRewired = rewire('.../../index/js');
describe('testing sync events', () => {
let stubMultiAccountInstance, MultiAccountInstanceReverter;
let accounts;
beforeEach(() => {
accounts = [{id: 1}, {id: 2}];
stubMultiAccountInstance= sinon.stub().returns({
all: () => Promise.resolve(accounts), // also tried with sinon.stub().resolves(accounts)
});
MultiAccountInstanceReverter = indexRewired.__set__('MultiAccountInstance', stubMultiAccountInstance);
});
afterEach(() => {
stubMultiAccountInstance.reset();
MultiAccountInstanceReverter();
});
it('testing', ()=> {
return indexRewired().then((resp) => {
expect(stubMultiAccountInstance).to.have.been.calledWith({someParams: true});
});
})
});
你知道我在做什么错吗?
回答如下:这里是单元测试解决方案:
index.js
:
const { MultiAccounts } = require('./some.js');
const Promise = require('bluebird');
let MultiAccountInstance = new MultiAccounts();
const syncEvents = () =>
Promise.try(() => {
return MultiAccountInstance.all().then((accounts) => console.log(accounts));
});
module.exports = syncEvents;
some.js
:
function MultiAccounts() {
async function all() {}
return {
all,
};
}
module.exports = { MultiAccounts };
index.test.js
:
const sinon = require('sinon');
const rewire = require('rewire');
const Promise = require('bluebird');
describe('61659908', () => {
afterEach(() => {
sinon.restore();
});
it('should pass', async () => {
const promiseTrySpy = sinon.spy(Promise, 'try');
const logSpy = sinon.spy(console, 'log');
const indexRewired = rewire('./');
const accounts = [{ id: 1 }, { id: 2 }];
const fakeMultiAccountInstance = {
all: sinon.stub().resolves(accounts),
};
indexRewired.__set__('MultiAccountInstance', fakeMultiAccountInstance);
await indexRewired();
sinon.assert.calledOnce(fakeMultiAccountInstance.all);
sinon.assert.calledWith(logSpy, [{ id: 1 }, { id: 2 }]);
sinon.assert.calledOnce(promiseTrySpy);
});
});
带有覆盖率报告的单元测试结果:
61659908
[ { id: 1 }, { id: 2 } ]
✓ should pass (54ms)
1 passing (62ms)
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 80 | 100 |
index.js | 100 | 100 | 100 | 100 |
some.js | 100 | 100 | 50 | 100 |
----------|---------|----------|---------|---------|-------------------
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如何使用sinon并重新接线来模拟另一个文件中定义的常量?
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