Javascript 如何为使用标准输出的东西编写测试?
我正在努力提高这个文件的测试覆盖率Javascript 如何为使用标准输出的东西编写测试?,javascript,node.js,unit-testing,mocha.js,bunyan,Javascript,Node.js,Unit Testing,Mocha.js,Bunyan,我正在努力提高这个文件的测试覆盖率 'use strict' /** * Returns the logging options we're using * * @param {String} name Name of the logger. Should be service name. e.g. ciitizen-file-service * @returns {Object} The logging options we're using * @private
'use strict'
/**
* Returns the logging options we're using
*
* @param {String} name Name of the logger. Should be service name. e.g. ciitizen-file-service
* @returns {Object} The logging options we're using
* @private
*/
function getLoggerOptions(name) {
return {
name: name,
streams: [
{
level: 'info',
stream: stdOutStream()
}, {
level: 'error',
stream: stdErrStream()
}
, {
level: 'debug',
stream: stdOutStream()
},
{
level: 'warn',
stream: stdOutStream()
},
{
level: 'fatal',
stream: stdErrStream()
}
]
}
}
/**
* Creates a stream that writes to stdout
*
* @param {Object} info The log info
* @returns {Object} An object which logs to stdout
* @private
*/
function stdOutStream() {
return {
write: log => {
// Change log level number to name and write it out
log.level = bunyan.nameFromLevel[log.level]
process.stdout.write(JSON.stringify(log) + '\n')
}
}
}
/**
* Creates a stream that writes to stderr
*
* @param {Object} info The log info
* @returns {Object} An object which logs to stderr
* @private
*/
function stdErrStream() {
return {
write: log => {
// Change log level number to name and write it out
log.level = bunyan.nameFromLevel[log.level]
process.stderr.write(JSON.stringify(log) + '\n')
}
}
}
module.exports = { getLoggerOptions }
我现在有这个测试
'use strict'
const expect = require('chai').expect
const { getLoggerOptions } = require('../src/helpers')
describe.only('#getLoggerOptions', () => {
it('should return the logger options', () => {
expect(getLoggerOptions('test')).to.be.an('object')
})
})
这导致了单元测试覆盖率的差距
如何编写测试来覆盖此代码?您只是断言
getLoggerOptions(…)
应该返回一个对象,但您没有访问该对象
例如,除了发布的测试之外,请尝试添加一个测试,如:
describe.only('#probeLoggerOptions', () => {
it('should do expected logging stuff', () => {
const {name, streams} = getLoggerOptions('test');
for (let stream of streams) {
console.log(`getting logopt for level ${stream.level}`);
expect(stream.stream.write(log), /* ... what to expect */);
}
});
});
现在,测试在每个对象中调用write
函数
EXTRA:如果您拥有代码,最好的方法是将其重构为更易于测试。例如,您可以创建一个writeablestream
,对其进行写入,然后通过管道传输到所需的流程,而不是直接写入高级流程
流
function configureStream(writable = process.stdout, data = null, msg = 'done') {
const stream = fs.createReadStream('/tmp/log');
stream.read(data);
stream.pipe(writable);
}
除了能够单独测试configureStream
之外,还可以将每个日志记录过程的内容抽象为一个函数,以减少测试工作量。现在,您还可以连接到流的事件,如“pipe”或“finish”,以检查正在记录的内容。您的第一个示例失败b/c日志未定义expect(stream.write(log)
当我将其更改为expect(stream.write('foo'))
我现在得到错误TypeError:stream.write不是一个函数
@Catfishlog
没有提供,因为我不知道它。你应该可以自己提供。对不起,流
这里有一个属性为level
和stream
的对象,因此你必须调用stre
am.stream.write(log)
。我更正了它。我正试图遵循您的“额外”,但您的代码不起作用。您无法创建这样的写入流。您需要传递字符串或缓冲区。我将其更改为'const myStream=fs.createWriteStream('foobar')myStream.write('foo')myStream.pipe(myStream)myStream.end()`现在我得到错误error[ERR\u STREAM\u CANNOT\u PIPE]:CANNOT PIPE,not readable
尝试使用存根(sinon.stub
)来测试这些功能。创建存根并测试调用了存根函数。
function stdOutStream() {
return {
write: log => {
// Change log level number to name and write it out
log.level = bunyan.nameFromLevel[log.level];
configureStream(data = JSON.stringify(log) + '\n');
}
}
}