toBe (true) vs toBeTruthy () vs toBeTrue ()

toBe (true) vs toBeTruthy () vs toBeTrue ()

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무엇 사이의 차이 expect(something).toBe(true), expect(something).toBeTruthy()그리고 expect(something).toBeTrue()?

참고 toBeTrue()A는 사용자 정의 정규 도입 jasmine-matchers과 같은 다른 유용하고 편리한 정합 기 중 toHaveMethod()또는 toBeArrayOfStrings().

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이 질문은 일반적인 것이지만 실제 예를 들어 요소가에 표시되는지 테스트하고 protractor있습니다. 이 경우 어떤 매처를 사용해야합니까?

expect(elm.isDisplayed()).toBe(true);
expect(elm.isDisplayed()).toBeTruthy();
expect(elm.isDisplayed()).toBeTrue();

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여기서 묻는 질문과 같은 궁금한 점이 있으면 소스로 이동하십시오.

되려고()

expect().toBe() 다음과 같이 정의됩니다.

function toBe() {
  return {
    compare: function(actual, expected) {
      return {
        pass: actual === expected
      };
    }
  };
}

테스트는 다음과 ===같이 사용될 때 실제로 값이있는 expect(foo).toBe(true)경우에만 통과 함을 의미합니다 . 진실한 가치는 시험을 통과시키지 못합니다.footrue

toBeTruthy ()

expect().toBeTruthy() 다음과 같이 정의됩니다.

function toBeTruthy() {
  return {
    compare: function(actual) {
      return {
        pass: !!actual
      };
    }
  };
}

강제 변환

이 값을 부울로 강제 변환하면 값이 생성되면 값이 진실 true입니다. 이 작업 은 부울에 !!전달 된 값을 강제 적용하여 진실성을 테스트합니다 expect. 반대로 현재 허용 대답은 무엇에주의 의미 , == true입니다 하지 truthiness에 대한 정확한 테스트. 당신은 같은 재미있는 것들을 얻을 것이다

> "hello" == true
false
> "" == true
false
> [] == true
false
> [1, 2, 3] == true
false

!!수율을 사용하는 반면 :

> !!"hello"
true
> !!""
false
> !![1, 2, 3]
true
> !![] 
true

(예, 비어 있든 아니든 배열은 진실입니다.)

toBeTrue ()

expect().toBeTrue()Jasmine-Matchers의 일부입니다 ( jasmine-expect나중에 프로젝트를 jasmine-matchers먼저 등록한 후 npm에 등록됨 ).

expect().toBeTrue() 다음과 같이 정의됩니다.

function toBeTrue(actual) {
  return actual === true ||
    is(actual, 'Boolean') &&
    actual.valueOf();
}

The difference with expect().toBeTrue() and expect().toBe(true) is that expect().toBeTrue() tests whether it is dealing with a Boolean object. expect(new Boolean(true)).toBe(true) would fail whereas expect(new Boolean(true)).toBeTrue() would pass. This is because of this funny thing:

> new Boolean(true) === true
false
> new Boolean(true) === false
false

At least it is truthy:

> !!new Boolean(true)
true

Which is best suited for use with elem.isDisplayed()?

Ultimately Protractor hands off this request to Selenium. The documentation states that the value produced by .isDisplayed() is a promise that resolves to a boolean. I would take it at face value and use .toBeTrue() or .toBe(true). If I found a case where the implementation returns truthy/falsy values, I would file a bug report.

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In javascript there are trues and truthys. When something is true it is obviously true or false. When something is truthy it may or may not be a boolean, but the "cast" value of is a boolean.

Examples.

true == true; // (true) true
1 == true; // (true) truthy
"hello" == true;  // (true) truthy
[1, 2, 3] == true; // (true) truthy
[] == false; // (true) truthy
false == false; // (true) true
0 == false; // (true) truthy
"" == false; // (true) truthy
undefined == false; // (true) truthy
null == false; // (true) truthy

This can make things simpler if you want to check if a string is set or an array has any values.

var users = [];

if(users) {
  // this array is populated. do something with the array
}

var name = "";

if(!name) {
  // you forgot to enter your name!
}

And as stated. expect(something).toBe(true) and expect(something).toBeTrue() is the same. But expect(something).toBeTruthy() is not the same as either of those.

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Disclamer: This is just a wild guess

I know everybody loves an easy-to-read list:

• toBe(<value>) - The returned value is the same as <value>
• toBeTrue() - Checks if the returned value is true

• toBeTruthy() - Check if the value, when cast to a boolean, will be a truthy value

  Truthy values are all values that aren't 0, '' (empty string), false, null, NaN, undefined or [] (empty array)*.

  _{* Notice that when you run !![], it returns true, but when you run [] == false it also returns true. It depends on how it is implemented. In other words: (!![]) === ([] == false)}

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On your example, toBe(true) and toBeTrue() will yield the same results.

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There are a lot many good answers out there, i just wanted to add a scenario where the usage of these expectations might be helpful. Using element.all(xxx), if i need to check if all elements are displayed at a single run, i can perform -

expect(element.all(xxx).isDisplayed()).toBeTruthy(); //Expectation passes
expect(element.all(xxx).isDisplayed()).toBe(true); //Expectation fails
expect(element.all(xxx).isDisplayed()).toBeTrue(); //Expectation fails

Reason being .all() returns an array of values and so all kinds of expectations(getText, isPresent, etc...) can be performed with toBeTruthy() when .all() comes into picture. Hope this helps.

참고URL : https://stackoverflow.com/questions/32615713/tobetrue-vs-tobetruthy-vs-tobetrue