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[英]Unit testing Javascript - Jasmine test fails although code is working as expected
[英]Testing if a Jasmine Test Fails
我正在尝试为Jasmine编写一个插件,允许您从规范中返回一个承诺,并根据是否履行承诺而拒绝该规范。
当然,我想编写测试以确保我的插件正常工作,并且要彻底,我需要确保在拒绝承诺时测试失败...所以当我需要时如何进行测试通过确保测试“成功失败”?
在与使用Jasmine的开发人员交谈后,我们想出了这个:
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()
})
})
在Joe的回答中,我将假测试上下文移动到一个函数中。 由于测试中的代码正在使用jasmine期望,我将内部Env
加载到jasmine.currentEnv_
并使用jasmine.currentEnv_.expect()
显式调用它。 请注意, currentEnv_
是由jasmine本身设置的内部变量,因此我不能保证在将来的jasmine版本中不会破坏它。
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");
});
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