Simple protractor test for isElementPresent failing with unsupported locator strategy

问题

My test:

it('should allow login', function() {
  browser.get('index.html');

  $('#username').sendKeys('administrator');
  $('#password').sendKeys('password');
  $('#login').click();

  var logout = $('#logout');
  expect($p.isElementPresent(logout)).to.eventually.be.true;
});

But this errors out with:

Error: Unsupported locator strategy: click
  at Error (<anonymous>)
  at Function.webdriver.Locator.createFromObj (/usr/local/lib/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/locators.js:97:9)
  at Function.webdriver.Locator.checkLocator (/usr/local/lib/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/locators.js:111:33)
  at webdriver.WebDriver.findElements (/usr/local/lib/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/webdriver.js:805:31)
  at webdriver.WebDriver.isElementPresent (/usr/local/lib/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/webdriver.js:787:29)
  at Protractor.isElementPresent (/usr/local/lib/node_modules/protractor/lib/protractor.js:476:22)
  at /Users/pschuegr/wt/client/e2e/login_test.js:26:15

Strangely, it points to the isElementPresent line, rather than the line with the click. I'm pretty new to webdriver, so apologies if I missed something obvious. I'm running using the mocha framework (which means the canary version of protractor), fwiw.

Any ideas appreciated.

回答1:

$('#logout') is a WebElement. isElementPresent takes a locator, like by.css

$('#username').sendKeys('administrator');
$('#password').sendKeys('password');
$('#login').click();

var logout = by.css('#logout');
browser.wait(function() { return $p.isElementPresent(logout); }, 8000);
expect($p.isElementPresent(logout)).toBeTruthy();

回答2:

Using the latest Protractor build, you can shorten the above answer to the following:

expect(element(by.css('#logout')).isPresent()).toBeTruthy();

This way you do not have to perform the browser.wait and you reduce the number of calls to isElementPresent.

回答3:

The safest approach I would take is depicted in the following code snippet:

it('should return true when element is present', function () {
 var logout;
 logout = $('#logout');

  browser.driver.isElementPresent(logout).then(function (isPresent) {
    isPresent = (isPresent) ? true : browser.wait(function () {
      return browser.driver.isElementPresent(logout );
    }, 15000); //timeout after 15s 
    expect(isPresent).toBeTruthy();
  });
});

Above code starts of with a promise to check if an element exists, and if true then assign it true, otherwise wait and keep pooling for the next 15sec to see if element is present, and in both cases we expect it to be true.

回答4:

This should work :

var logout = $('#logout');
expect(logout.isPresent()).to.eventually.be.true;

来源：https://stackoverflow.com/questions/21245418/simple-protractor-test-for-iselementpresent-failing-with-unsupported-locator-str

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angularjs

mocha

protractor