Getting error: Error while waiting for Protractor to sync with the page: {}

Question 1

The (very) short version: use browser.driver.get instead of browser.get.

The longer version: Protractor is basically a wrapper around Selenium and its Javascript WebDriver code. Protractor adds code to wait for Angular to "settle down" (i.e., finish going through its $digest loops) before proceeding with your test code. However, if your page doesn't have Angular on it, then Protractor will wait "forever" (actually just until it times out) waiting for Angular to settle.

The browser object that Protractor exposes to your test is an instance of Protractor (i.e., if you see old answers on Stack Overflow with var ptor = protractor.getInstance(); ptor.doSomething(), then you can replace ptor with browser in those old answers). Protractor also exposes the wrapped Selenium WebDriver API as browser.driver. So if you call browser.get, you're using Protractor (and it will wait for Angular to settle down), but if you call browser.driver.get, you're using Selenium (which does not know about Angular).

Most of the time, you'll be testing Angular pages, so you'll want to use browser.get to get the benefits of Protractor. But if your login page doesn't use Angular at all, then you should be using browser.driver.get instead of browser.get in the tests that test your login page. Do note that you'll also need to use the Selenium API rather than the Protractor API in the rest of the test: for example, if you have an HTML input element with id="username" somewhere in your page, you'll want to access it with browser.driver.findElement(by.id('username')) instead of element(by.model('username')).

For more examples, see this example from the Protractor test suite (or try this link if the previous one ever goes away). See also the Protractor docs which state:

Protractor will fail when it cannot find the Angular library on a page. If your test needs to interact with a non-angular page, access the webdriver instance directly with browser.driver.

Example code: In your login test above, you would want to do something like:

describe 'Logging in', ->
  it 'should show the login page', ->
    browser.driver.get "http://my.site/login.html"
    // Wait for a specific element to appear before moving on
    browser.driver.wait ->
      browser.driver.isElementPresent(by.id("username"))
    , 1200
    expect(browser.driver.getCurrentUrl()).toMatch("/login.html");
  it 'should login', ->
    // We're still on the login page after running the previous test
    browser.driver.findElement(by.id("username")).sendKeys("some_username")
    browser.driver.findElement(by.id("password")).sendKeys("some_password")
    browser.driver.findElement(by.xpath('//input[@type="submit"]')).click()

(A note of caution: I haven't done much CoffeeScript, and it's entirely possible I made a CoffeeScript syntax error in the code above. You may want to check its syntax before blindly copying and pasting it. I am, however, confident in the logic, because that's copied and pasted almost verbatim from my Javascript code that tests a non-Angular login page.)

Question 2

If you need to be using browser.get and are getting this error, the issue is most likely to be the rootElement property in protractor config file.

By default Protractor assumes that the ng-app declaration sits on the BODY-element. However, in our case, it could be declared somewhere else in the DOM. So we have to assign the selector of that element to the rootElement property:

// rootElement: 'body', // default, but does not work in my case
rootElement: '.my-app', // or whatever selector the ng-app element has

Corresponding HTML:

<div ng-app="myApp" class="my-app">

I copied the answer from http://www.tomgreuter.nl/tech/2014/03/timing-errors-with-angular-protractor-testing/

Question 3

I got this error, too, but in my case my tests were working and this error occured after expanding them.

Turns out that this error may occur, if you try to call getText() in your describe block instead of your testcases. My Set-Up was like following:

describe('Test Edit Functionality', function() {
    var testEntry = $$('.list-entry').first(),
        testEntryOldName = testEntry.getText();

   it('Should keep old name if edit is aborted', [...]);
});

That caused the Error Error while waiting for Protractor to sync with the page: {}.

I fixed it by moving the assigment into a beforeEach-block

describe('Test Delete Functionality', function() {
    var testEntry = $$('.list-entry').first(),
        testEntryOldName;

   beforeEach(function() {
        testEntryOldName = testEntry.getText();
   });
});

Or, may be better, assign it in the specific testcases you need this value (if you dont need it in all).

Question 4

Not sure where I picked up the pieces that put this answer at this point, but this is what works for me:

Add class='ng-app' to the element that contains your app.

<div ng-app="myApp" ng-controller="myController" class="ng-app"></div>

Add rootElement to your protractor.conf.

exports.config = {
  specs: ['your-spec.js'],
  rootElement: ".ng-app"
};

Use browser.driver.get not browser.get.

describe('foobar element', function() {
  it('should be "baz" after view is initialized', function() {
  browser.driver.get('http://localhost/view');

    var inputBox = $('input[name=foobar]');
    expect(inputBox.getAttribute('value')).toEqual("baz");
  });
});

Question 5

I got this issue a couple of days back on my CT. My tests were running fine until 3 days back, but then this protractor sync error showed up and just won't go away with any of the solutions/hacks provided here and at https://github.com/angular/protractor/issues/2643.

I checked that this issue only occurred in Firefox headless and worked fine with Chrome headless. Upgrading from Firefox v69 to the latest(v72 currently) fixed the issue. I do not know why the issue started manifesting itself and how it got fixed with the upgrade, but for what it is worth I thought this information might come in handy for someone else.