【发布时间】:2015-12-13 13:08:27
【问题描述】:
我正在尝试为Jasmine 编写一个插件,它允许您从规范中返回一个承诺,并根据承诺是否被履行或拒绝而通过或失败该规范。
当然,我想编写测试以确保我的插件正常工作,并且要彻底,我需要确保当 promise 被拒绝时测试失败......所以我如何让测试通过我需要确保测试“成功失败”?
【问题讨论】:
标签: javascript unit-testing testing jasmine
我正在尝试为Jasmine 编写一个插件,它允许您从规范中返回一个承诺,并根据承诺是否被履行或拒绝而通过或失败该规范。
当然,我想编写测试以确保我的插件正常工作,并且要彻底,我需要确保当 promise 被拒绝时测试失败......所以我如何让测试通过我需要确保测试“成功失败”?
【问题讨论】:
标签: javascript unit-testing testing jasmine
在与 Jasmine 的开发人员交谈后,我们得出了以下结论:
var FAILED = 'failed'
var PASSED = 'passed'
describe('My Test Suite', function () {
var env
beforeEach(function () {
// Create a secondary Jasmine environment to run your sub-specs in
env = new jasmine.Env()
})
it('should work synchronously', function () {
var spec
// use the methods on `env` rather than the global ones for sub-specs
// (describe, it, expect, beforeEach, etc)
env.describe('faux suite', function () {
spec = env.it('faux test', function (done) {
env.expect(true).toBe(true)
})
})
// this will fire off the specs in the secondary environment
env.execute()
// put your expectations here if the sub-spec is synchronous
// `spec.result` has the status information we need
expect(spec.result.status).toBe(FAILED)
})
// don't forget the `done` argument for asynchronous specs
it('should work asynchronously', function (done) {
var spec
// use the methods on `env` rather than the global ones.
env.describe('faux suite', function () {
// `it` returns a spec object that we can use later
spec = env.it('faux test', function (done) {
Promise.reject("FAIL").then(done)
})
})
// this allows us to run code after we know the spec has finished
env.addReporter({jasmineDone: function() {
// put your expectations in here if the sub-spec is asynchronous
// `spec.result` has the status information we need
expect(spec.result.status).toBe(FAILED)
// this is how Jasmine knows you've completed something asynchronous
// you need to add it as an argument to the main `it` call above
done()
}})
// this will fire off the specs in the secondary environment
env.execute()
})
})
【讨论】:
根据 Joe 的回答,我将伪造的测试上下文移到了一个函数中。由于被测代码使用 jasmine 期望,我将内部 Env 加载到 jasmine.currentEnv_ 并使用 jasmine.currentEnv_.expect() 显式调用它。注意currentEnv_是jasmine自己设置的内部变量,所以我不能保证在以后的jasmine版本中不会被破坏。
function internalTest(testFunc) {
var outerEnvironment = jasmine.currentEnv_;
var env = new jasmine.Env();
jasmine.currentEnv_ = env;
var spec;
env.describe("fake suite", function () {
spec = env.it("fake test", function () {
func();
});
});
env.execute();
jasmine.currentEnv_ = outerEnvironment;
return spec.result;
}
然后每个测试看起来像
it("does something", function () {
//Arrange
//Act
var result = internalTest(function () {
//Perform action
});
//Assert
expect(result.status).toBe("failed"); //Or "success"
expect(result.failedExpectations.length).toBe(1);
expect(result.failedExpectations[0].message).toBe("My expected error message");
});
【讨论】:
env 作为参数传递给func,而不是使用jasmine.currentEnv_。另外,你如何处理异步规范的情况?