Failed expectation: "Expected [ ] to be empty array."

Question

Here is the failing test:

describe("Checking errors", function () {
    var scope = {};

    beforeEach(function () {
        browser.get("/#endpoint");
        browser.waitForAngular();

        scope.page = new MyPage();
    });

    it("should not show any errors", function () {
        expect(scope.page.errors).toBeEmptyArray();
    });
});

where MyPage is a Page Object:

var MyPage = function () {
    this.errors = element.all(by.css("div.error-block b.error"))
        .filter(function (elm) {
            return elm.isDisplayed().then(function (value) {
                return value;
            });
        })
        .map(function (elm) {
            return elm.getText();
        });
};

module.exports = MyPage;

where errors supposed to be an array of visible error texts found on a page.

Here is the error we are getting:

Failures:

  1) Checking errors should not show any errors
   Message:
     Expected [  ] to be empty array.
   Stacktrace:
     Error: Failed expectation

FYI, toBeEmptyArray() matcher is coming from jasmine-matchers third-party.

I've tried to print out the value of scope.page.errors this way:

scope.page.errors.then(function (errors) {
    console.log(errors);
});

And it is printed out as []. Array.isArray(errors) returns true.

From what I see, scope.page.errors is an empty array, but the expectation fails. What I a missing?

@Ryan was not expecting this, but it prints true..weird. Thanks. — alecxe
– alecxe, Commented Mar 18, 2015 at 23:15
Does expect(scope.page.errors.length).toBe(0); work? You might be running into a problem from the scopes webdriver creates (like iframes in a page) that have their own "Array" definition. See stackoverflow.com/a/2265999/960524 (so this might be a bug in the toBeEmptyArray() method -- its probably failing the "array"-ness part of the check.) — P.T.
– P.T., Commented Mar 18, 2015 at 23:36
@P.T. thank you for the point, the expectation you've posted fails with Expected undefined to be 0. I actually suspect this has smth to do with ElementArrayFinder..this particular comment could be related to what we are experiencing: You can treat an ElementArrayFinder as an array of WebElements for most purposes... — alecxe
– alecxe, Commented Mar 18, 2015 at 23:45

alecxe · Accepted Answer · 2015-04-08 16:22:08Z

3

+100

the answer is four lines down in the protractor src.

ElementArrayFinder extends Promise, while jasmine-matchers checks first checks that errors is an actual array exactly how Array.isArray is done , which will return false;

This is also consistent with expect(scope.page.errors.length).toBe(0) being undefined because promises do not have lengths.

Just run errors.then on your promise, and test that the argument is [] You've also shown that can be done when you ran scope.page.errors.then

edited Apr 8, 2015 at 16:22

alecxe

476k127 gold badges1.1k silver badges1.2k bronze badges

answered Apr 8, 2015 at 7:14

michael truong

3111 silver badge4 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

alecxe Over a year ago

Thank you, this is what I've suspected (see comments). Though, resolving scope.page.errors with then() didn't help: Expected [ ] to be empty array. when using the following code: scope.page.errors.then(function (errors) { expect(errors).toBeEmptyArray(); });.

alecxe Over a year ago

In other words, even the resolved value is not an array, it looks like an array but it's not (forget about the "duck" principle :)). But, now I have a workaround - I'm making an array out of "almost an array": expect([].concat(errors)).toBeEmptyArray();. Worth +1 anyway.

michael truong Over a year ago

unfortunately, their implementation does not follow the 'duck' principle by testing the toString of the object

samyak bhalerao · Accepted Answer · 2015-04-08 07:29:28Z

0

Inside test script your code line "scope.page = new MyPage();" is creating new empty MyPage object.Code which you have written in application script is creating page object locally and its not bounded with any angular scope.When there is requirement of testing such objects you need to replicate code for page object creation in beforeEach(); block of test script.And test it.
 describe("Checking errors", function () {
    var scope = {};
     var MyPage ;
    beforeEach(function () {
        browser.get("/#endpoint");
        browser.waitForAngular();

       MyPage = function () {
    this.errors = element.all(by.css("div.error-block b.error"))
        .filter(function (elm) {
            return elm.isDisplayed().then(function (value) {
                return value;
            });
        })
        .map(function (elm) {
            return elm.getText();
        });
};
    });

    it("should not show any errors", function () {
        expect(MyPage.errors).toBeEmptyArray();
    });
});

answered Apr 8, 2015 at 7:29

samyak bhalerao

3072 silver badges10 bronze badges

1 Comment

alecxe Over a year ago

Thank you for the participation, though it doesn't answer the question.

Collectives™ on Stack Overflow

Failed expectation: "Expected [ ] to be empty array."

2 Answers 2

3 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related