自動化端對端測試框架－Protractor Reference 2

Timeouts

Because WebDriver tests are asynchronous and involve many components, there are several reasons why a timeout could occur in a Protractor test.

Timeouts from Protractor

Waiting for Page to Load

When navigating to a new page using browser.get, Protractor waits for the page to be loaded and the new URL to appear before continuing.

• Looks like: an error in your test results - Error: Timed out waiting for page to load after 10000ms

• Default timeout: 10 seconds

• How to change: To change globally, add getPageTimeout: timeout_in_millis to your Protractor configuration file. For an individual call to get, pass an additional parameter: browser.get(address, timeout_in_millis)

Waiting for Page Synchronization

Before performing any action, Protractor asks Angular to wait until the page is synchronized. This means that all timeouts and http requests are finished. If your application continuously polls $timeout or $http, it will never be registered as completely loaded. You should use the $interval service (interval.js) for anything that polls continuously (introduced in Angular 1.2rc3).

• Looks like: an error in your test results - Timed out waiting for Protractor to synchronize with the page after 11 seconds.

• Default timeout: 11 seconds

• How to change: Add allScriptsTimeout: timeout_in_millis to your Protractor configuration file.

Waiting for Angular

Protractor only works with Angular applications, so it waits for the angular variable to be present when it is loading a new page.

• Looks like: an error in your test results - Angular could not be found on the page: retries looking for angular exceeded

• Default timeout: 10 seconds

• How to change: To change globally, add getPageTimeout: timeout_in_millis to your Protractor configuration file. For an individual call to get, pass an additional parameter: browser.get(address, timeout_in_millis)

How to disable waiting for Angular

If you need to navigate to a page which does not use Angular, you can turn off waiting for Angular by setting browser.ignoreSynchronization = true. For example:

browser.get('page-containing-angular');navigateToVanillaPage.click();browser.ignoreSynchronization = true;otherButton.click();navigateToAngularPage.click();browser.ignoreSynchronization = false;

Timeouts from WebDriver

Asynchronous Script Timeout

Sets the amount of time to wait for an asynchronous script to finish execution before throwing an error.

• Looks like: an error in your test results - ScriptTimeoutError: asynchronous script timeout: result was not received in 11 seconds

• Default timeout: 11 seconds

• How to change: Add allScriptsTimeout: timeout_in_millis to your Protractor configuration file.

Timeouts from Jasmine

Spec Timeout

If a spec (an 'it' block) takes longer than the Jasmine timeout for any reason, it will fail.

• Looks like: a failure in your test results - timeout: timed out after 30000 msec waiting for spec to complete

• Default timeout: 30 seconds

• How to change: To change for all specs, add jasmineNodeOpts: {defaultTimeoutInterval: timeout_in_millis} to your Protractor configuration file. To change for one individual spec, pass a third parameter to it: it(description, testFn, timeout_in_millis).

Timeouts from Sauce Labs

If you are using Sauce Labs, there are a couple additional ways your test can time out. See Sauce Labs Timeouts Documentation for more information.

Maximum Test Duration

Sauce Labs limits the maximum total duration for a test.

• Looks like: Test exceeded maximum duration after 1800 seconds

• Default timeout: 30 minutes

• How to change: Edit the "max-duration" key in the capabilities object.

Command Timeout

As a safety measure to prevent Selenium crashes from making your tests run indefinitely, Sauce limits how long Selenium can take to run a command in browsers. This is set to 300 seconds by default.

• Looks like: Selenium took too long to run your command

• Default timeout: 300 seconds

• How to change: Edit the "command-timeout" key in the capabilities object.

Idle Timeout

As a safety measure to prevent tests from running too long after something has gone wrong, Sauce limits how long a browser can wait for a test to send a new command. This is set to 90 seconds by default. You can adjust this limit on a per-job basis.

• Looks like: Test did not see a new command for 90 seconds. Timing out.

• Default timeout: 90 seconds

• How to change: Edit the "idle-duration" key in the capabilities object.

The WebDriver Control Flow

The WebDriverJS API is based on promises, which are managed by a control flow and adapted for Jasmine. A short summary about how Protractor interacts with the control flow is presented below.

Promises and the Control Flow

WebDriverJS (and thus, Protractor) APIs are entirely asynchronous. All functions return promises.

WebDriverJS maintains a queue of pending promises, called the control flow, to keep execution organized. For example, consider this test:

  it('should find an element by text input model', function() {
    browser.get('app/index.html#/form');

    var username = element(by.model('username'));
    username.clear();
    username.sendKeys('Jane Doe');

    var name = element(by.binding('username'));

    expect(name.getText()).toEqual('Jane Doe');

    // Point A
  });

At Point A, none of the tasks have executed yet. The browser.get call is at the front of the control flow queue, and the name.getText() call is at the back. The value of name.getText() at point A is an unresolved promise object.

Protractor Adaptations

Protractor adapts Jasmine so that each spec automatically waits until the control flow is empty before exiting.

Jasmine expectations are also adapted to understand promises. That's why this line works - the code actually adds an expectation task to the control flow, which will run after the other tasks:

  expect(name.getText()).toEqual('Jane Doe');

Mocha Users

If you are using Mocha as your test framework, the control flow will still automatically empty itself before each test completes. However, the expectfunction in Mocha is not adapted to understand promises - that's why you'll need to use an assertion framework such as Chai as Promised. SeeChoosing a Framework for more information.