我正在尝试模拟pg promise库。我希望无论承诺拒绝还是解决都能够模拟返回。这是一个示例函数和测试:
const pgp = require('pg-promise')({});
const someFunc = callback => {
const db = pgp('connectionString');
db
.none('create database test;')
.then(() => {
callback(null, 'success');
})
.catch(err => {
callback(err);
});
};
module.exports = {
someFunc
};
我想这样测试:
const { someFunc } = require('./temp');
let pgp = require('pg-promise')({
noLocking: true
});
// HOW TO MOCK?
describe('test', () => {
beforeEach(() => {
jest.resetModules();
jest.resetAllMocks();
});
it('should test', () => {
let db = pgp('connectionString');
// how to mock this?
db.none = jest.fn();
db.none.mockReturnValue(Promise.reject('mock'));
const callback = jest.fn();
someFunc(callback);
return new Promise(resolve => setImmediate(resolve)).then(() => {
expect(callback.mock.calls.length).toEqual(1);
});
});
});
最佳答案
您可以使用哑模拟来模拟pgp
对象,如下所示:
const { someFunc } = require('./temp');
let pgp = jest.fn(() => ({
none: jest.fn(),
})
jest.mock('pg-promise') // Jest will hoist this line to the top of the file
// and prevent you from accidentially calling the
// real package.
describe('test', () => {
beforeEach(() => {
jest.resetModules();
jest.resetAllMocks();
});
it('should test', () => {
let db = pgp('connectionString');
db.none.mockRejectedValue('mock'); // This is the mock
const callback = jest.fn();
someFunc(callback);
return new Promise(resolve => setImmediate(resolve)).then(() => {
expect(callback.mock.calls.length).toEqual(1);
});
});
});
关于unit-testing - 如何用玩笑 mock pg-promise库,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/47456900/