如何为chai Expect提供用于摩卡单元测试的自定义错误消息? [英] How to provide chai expect with custom error message for mocha unit test?
本文介绍了如何为chai Expect提供用于摩卡单元测试的自定义错误消息?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我使用chai的期望进行了摩卡测试:
I have a mocha test using chai's expect:
it("should parse sails out of cache file", async () => {
const sailExtractor = new Extractor();
const result = await sailExtractor.extract("test.xml");
try {
expect(result.length).to.be.greaterThan(0);
const withMandatoryFlight = result.filter((cruises) => {
return cruises.hasMandatoryFlight === true;
});
expect(withMandatoryFlight.length).to.be.greaterThan(0);
const cruiseOnly = result.filter((cruises) => {
return cruises.hasMandatoryFlight === false;
});
expect(cruiseOnly.length).to.be.greaterThan(0);
return Promise.resolve();
} catch (e) {
return Promise.reject(e);
}
}
现在,如果一个 to.be.greaterThan(0)
期望失败,则错误输出a不是对开发人员友好的:
Now if one to.be.greaterThan(0)
expectation fails, the error output on mocha is not dev-friendly:
AssertionError: expected 0 to be above 0
at Assertion.assertAbove (node_modules/chai/lib/chai/core/assertions.js:571:12)
at Assertion.ctx.(anonymous function) [as greaterThan] (node_modules/chai/lib/chai/utils/addMethod.js:41:25)
at _callee2$ (tests/unit/operator/croisiEurope/CroisXmlExtractorTest.js:409:61)
at tryCatch (node_modules/regenerator-runtime/runtime.js:65:40)
at Generator.invoke [as _invoke] (node_modules/regenerator-runtime/runtime.js:303:22)
at Generator.prototype.(anonymous function) [as next] (node_modules/regenerator-runtime/runtime.js:117:21)
at fulfilled (node_modules/tslib/tslib.js:93:62)
at <anonymous>
at process._tickDomainCallback (internal/process/next_tick.js:228:7)
我想用更人性化的东西代替它。有没有办法告诉chai使用自定义错误消息?
I would like to replace it with something more human-friendly. Is there a way to tell chai to use a customize error message?
我希望能够像下面的伪代码一样使用它:
I want to be able to use it like this pseudo-code:
expect(result.length)
.to.be.greaterThan(0)
.withErrorMessage("It should parse at least one sail out of the flatfile, but result is empty");
然后出现失败的摩卡错误:
And then the failing mocha error should print:
AssertionError: It should parse at least one sail out of the flatfile, but result is empty
推荐答案
每个期望
方法都接受可选参数 message
:
Every expect
method accepts an optional parameter message
:
expect(1).to.be.above(2, 'nooo why fail??');
expect(1, 'nooo why fail??').to.be.above(2);
因此,在您的情况下,应为:
So, in your case it should be:
expect(result.length)
.to.be.greaterThan(0, "It should parse at least one sail out of the flatfile, but result is empty");
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