Javascript 使用Jest.js模拟复杂模块
这就是我想要模拟的模块的样子:Javascript 使用Jest.js模拟复杂模块,javascript,jestjs,web3,Javascript,Jestjs,Web3,这就是我想要模拟的模块的样子: class TheModule { constructor() { this.subClass = new SubClass(); } } class SubClass { constructor() { this.someMethod = () => 'Did Something great'; } } module.exports = TheModule; 这是我要测试的模块用法: const TheModule
class TheModule {
constructor() {
this.subClass = new SubClass();
}
}
class SubClass {
constructor() {
this.someMethod = () => 'Did Something great';
}
}
module.exports = TheModule;
这是我要测试的模块用法:
const TheModule = require('./TheModule');
const method = () => {
const theModule = new TheModule();
return theModule.subClass.someMethod();
}
module.exports = method;
这是我的测试:
describe('method test', () => {
it('should return "Test pass"', () => {
jest.doMock('./TheModule');
const theModuleMock = require('./TheModule');
const method = require('./TheModuleUsage');
const mock = () => 'Test pass';
theModuleMock.subClass.someMethod.mockImplementation(() => mock);
expect(method()).toEqual('Test pass');
});
});
当我运行此测试时,我得到TypeError:无法读取未定义的属性“someMethod”
是否可以在不更改
模块
实现的情况下模拟此模块?如果要导出子类
,则可以在不更改模块
的情况下模拟此模块,但在您的情况下,应使用factory显式模拟模块
中的子类
属性,例如:
describe('method test', () => {
it('should return "Test pass"', () => {
let mockedSomeMethod = jest.fn().mockImplementation(() => 'Test pass');
jest.doMock('./TheModule', () => {
// mock constructor
return jest.fn().mockImplementation(() => {
return { subClass: { someMethod: mockedSomeMethod } }
});
});
const method = require('./TheModuleUsage');
expect(method()).toEqual('Test pass');
});
});