我正在尝试在process.on('SIGTERM')
回调中使用Jest对计时器进行单元测试,但似乎从未调用过它。我正在使用jest.useFakeTimers()
,虽然它似乎在一定程度上模拟了setTimeout
调用,但在检查它时并没有最终出现在setTimeout.mock
对象中。
我的index.js文件:
process.on('SIGTERM', () => {
console.log('Got SIGTERM');
setTimeout(() => {
console.log('Timer was run');
}, 300);
});
setTimeout(() => {
console.log('Timer 2 was run');
}, 30000);
和测试文件:
describe('Test process SIGTERM handler', () => {
test.only('runs timeout', () => {
jest.useFakeTimers();
process.exit = jest.fn();
require('./index.js');
process.kill(process.pid, 'SIGTERM');
jest.runAllTimers();
expect(setTimeout.mock.calls.length).toBe(2);
});
});
并且测试失败:
console.log tmp/index.js:10
Timer 2 was run
console.log tmp/index.js:2
Got SIGTERM
我如何在此处运行
setTimeout
? 最佳答案
可以做的是模拟流程on
方法,以确保将在kill
方法上调用您的处理程序。
确保将调用处理程序的一种方法是模拟kill
和on
。
describe('Test process SIGTERM handler', () => {
test.only('runs timeout', () => {
jest.useFakeTimers();
processEvents = {};
process.on = jest.fn((signal, cb) => {
processEvents[signal] = cb;
});
process.kill = jest.fn((pid, signal) => {
processEvents[signal]();
});
require('./index.js');
process.kill(process.pid, 'SIGTERM');
jest.runAllTimers();
expect(setTimeout.mock.calls.length).toBe(2);
});
});
另一种更通用的方法是在
setTimeout
中模拟处理程序并测试已被调用的代码,如下所示:index.js
var handlers = require('./handlers');
process.on('SIGTERM', () => {
console.log('Got SIGTERM');
setTimeout(handlers.someFunction, 300);
});
handlers.js
module.exports = {
someFunction: () => {}
};
index.spec.js
describe('Test process SIGTERM handler', () => {
test.only('sets someFunction as a SIGTERM handler', () => {
jest.useFakeTimers();
process.on = jest.fn((signal, cb) => {
if (signal === 'SIGTERM') {
cb();
}
});
var handlerMock = jest.fn();
jest.setMock('./handlers', {
someFunction: handlerMock
});
require('./index');
jest.runAllTimers();
expect(handlerMock).toHaveBeenCalledTimes(1);
});
});