我在监视从 Node 模块导入的函数时遇到问题。我正在测试一个子类，该模块是在祖父类中导入的，我需要查看调用该函数时使用的参数。
代码按预期工作，但我已经用 Jasmine 的内置 spyOn 和 sinon.spy 进行了测试，但两个 spy 都没有被调用。
代码:
// ChildClass.js
const ParentClass = require('./ParentClass');
module.exports = class ChildClass extends ParentClass {
constructor () {
super();
this.foo();
}
foo () {
this.message = this.importGetter('Some input');
}
};
// ParentClass.js
const GrandparentClass = require('./GrandparentClass');
module.exports = class ParentClass extends GrandparentClass {
constructor () {
super();
this._message = null;
}
get message () {
return this._message;
}
set message (value) {
this._message = value;
}
};
// GrandparentClass.js
const nodeModuleFunction = require('./nodeModule').nodeModuleFunction;
module.exports = class GrandparentClass {
get importGetter () {
return nodeModuleFunction;
}
};
// nodeModule.js
async function nodeModuleFunction (input) {
console.error('Do something with input: ', input);
return new Promise((resolve, reject) => {
setTimeout(() => {
resolve('Returned from node module.');
}, 300);
});
}
exports.nodeModuleFunction = nodeModuleFunction;
测试代码:
// test.spec.js
const ChildClass = require('./ChildClass');
const nodeModule = require('./nodeModule');
const sinon = require('sinon');
describe('ChildClass test', () => {
describe('Jasmine spy', () => {
it('should call nodeModule.nodeModuleFunction with given value', done => {
spyOn(nodeModule, 'nodeModuleFunction').and.callThrough();
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalled();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalledWith('Some input');
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
});
describe('Sinon spy', () => {
it('should call nodeModule.nodeModuleFunction with given value', done => {
const spy = sinon.spy(nodeModule, 'nodeModuleFunction');
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(spy.called).toBe(true);
expect(spy.withArgs('Some input').calledOnce).toBe(true);
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
});
});
测试结果:
Jasmine started
Do something with input: Some input
ChildClass test
Jasmine spy
✗ should call nodeModule.nodeModuleFunction with given value
- Expected spy nodeModuleFunction to have been called.
- Expected spy nodeModuleFunction to have been called with [ 'Some input' ] but it was never called.
Do something with input: Some input
Sinon spy
✗ should call nodeModule.nodeModuleFunction with given value
- Expected false to be true.
- Expected false to be true.
根据 Brian 的建议使用解决方案进行编辑:
const nodeModule = require('./nodeModule');
describe('ChildClass test', () => {
let ChildClass;
beforeAll(() => {
spyOn(nodeModule, 'nodeModuleFunction').and.callThrough(); // create the spy...
ChildClass = require('./ChildClass'); // ...and now require ChildClass
});
afterEach(() => {
nodeModule.nodeModuleFunction.calls.reset();
});
describe('Jasmine spy', () => {
it('should call nodeModule.nodeModuleFunction with given value', done => {
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalled();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalledWith('Some input');
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
it('should still call nodeModule.nodeModuleFunction with given value', done => {
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalled();
expect(nodeModule.nodeModuleFunction).toHaveBeenCalledWith('Some input');
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
});
});
const nodeModule = require('./nodeModule');
const sinon = require('sinon');
describe('ChildClass test', () => {
let spy;
let ChildClass;
beforeAll(() => {
spy = sinon.spy(nodeModule, 'nodeModuleFunction'); // create the spy...
ChildClass = require('./ChildClass'); // ...and now require ChildClass
});
afterEach(() => {
spy.resetHistory();
});
afterAll(() => {
spy.restore();
});
describe('Sinon spy', () => {
it('should call nodeModule.nodeModuleFunction with given value', done => {
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(spy.called).toBe(true);
expect(spy.withArgs('Some input').calledOnce).toBe(true);
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
it('should still call nodeModule.nodeModuleFunction with given value', done => {
const object = new ChildClass();
expect(object.message).not.toBeNull();
expect(spy.called).toBe(true);
expect(spy.withArgs('Some input').calledOnce).toBe(true);
object.message.then(message => {
expect(message).toBe('Returned from node module.');
done();
});
});
});
});
最佳答案
GrandparentClass.js 需要 nodeModule.js 并在它运行时获取对 nodeModuleFunction 的引用 。 ..
...所以你只需要确保你的 spy 在它运行之前就位:
const nodeModule = require('./nodeModule');
const sinon = require('sinon');
describe('ChildClass test', () => {
describe('Sinon spy', () => {
it('should call nodeModule.nodeModuleFunction with given value', done => {
const spy = sinon.spy(nodeModule, 'nodeModuleFunction'); // create the spy...
const ChildClass = require('./ChildClass'); // ...and now require ChildClass
const object = new ChildClass();
expect(object.message).not.toBeNull(); // Success!
expect(spy.called).toBe(true); // Success!
expect(spy.withArgs('Some input').calledOnce).toBe(true); // Success!
object.message.then(message => {
expect(message).toBe('Returned from node module.'); // Success!
done();
});
});
});
});
我更新了 Sinon 测试，但该方法也适用于 Jasmine 测试。
关于javascript - 测试子类时如何监视祖父类中的导入函数？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55762271/