Selenium WebDriver

Gianluca Carbone

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Contents

• What is Selenium?

• History

• WebDriver

• High-Level Architectures

• Architectural themes

• Non – Functional quality

• Layers & Javascript

• Design issues

• Firefox driver

• IE driver

• Who use Selenium

• Future problems

• Demonstration of a driverSelenium WebDriver 2

What is Selenium?

Selenium is a set of tools for cross-platform automated testing of web applications.

• Open Source Web Application Testing System

• Automated UI Testing

• Functional type of tests

• Multiple browsers, multiple languages

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Selenium

• History

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Selenium(1)- OverviewSelenium Core: JavaScript Framework

- IDE

Firefox Plugin

- Remote Control

Javascript code of Selenium Core

Server: Proxy to launch browsers

Client libraries

- Grid

Distributed remote tests

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WebDriver

A platform and language-neutral interface that allows programs or scripts to introspect into, and control the behavior of a web browser.(W3C)

• Clean & Object Oriented API

• Java bindings

• Attempted to bind natively to the browser

• HtmlWebDriver

• Overcomes the limitation of Selenium RC “Same Origin Policy”

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Selenium 1.0 Architecture

• High level architecture

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Selenium “2.0” Architecture

• High level architecture

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Architectural themes

• Keep the costs down

• Emulate the user

• Prove the drivers work…

• …but you should not need to understand how everything

works

• Lower the bus factor

• Have sympathy for Javascript implementation

• Every method call is an RPC call

• We are an Open Source project

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Non-functional quality

- Scalability

- Portability

- Compatibility

- Integrability/Reusability

- Customizability

- Usability

- Testability

- Ease of support

- Resilience/Maintainability

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Layers and Javascript

• A browser automation tool is essentially built of three moving

parts:

1. A way of interrogating the DOM (Document Object Model)

2. A mechanism for executing Javascript

3. Some means of emulating user input

Language : Javascript

Selenium makes use of a layered set of libraries

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Layers and Javascript (2)

• Adapter layers: in order to meet the API

contracts of both WebDriver and Core.

• Atoms: that provides functions for simple

tasks or complex actions.

• Google’s Clousure Library: which supplies

primitives and a modularization mechanism

allowing source file to be kept focused and

small as possibileSelenium WebDriver 12

Issue

• Operating Systems, Drivers and Programming

Languages supported:

Operating Systems :

Bindings: C#, Java, Ruby, Python, (Php and Perl

made by third part).

WebDriver API:

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Issue(2)

• Simplified Architecture -> Selenium Server NOT

needed.

- using only the WebDriver API

- browser and tests will all run on the same machine

• Otherwise you need it : - Selenium Grid;

- Connect to a remote machine with a particular browser

- Not using the Java bindings and would like to use HtmlUnitDriver

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Issue(3)

• Dealing with Combinatorial Explosion� Reducing the number of language

� Reducing the number of supported browsers

� Make all the browsers look identical to the language bindings with a uniform interface.

• Have sympathy for a JavaScript Implementation� Problem in the future, already with HTML 5

� Do not worry!

• Flaws in the WebDriver Design� RenderedWebElement Interface

� Documentation

� Binding tightly to a browser

� HTTP status code!

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Issue (4) - Architectural Style &

Design Pattern• Architectural Style

� Layered

� Plugin

Born as a plugin for firefox and always new features can be added to it

• Design Patterns � Components – InteroperabilityEnable communication between different platform (Web driver and Selenium Core)

� Composition Reuse of an existing applications – Selenium Core

Build system out of the composition of existing ones

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ISSUE (5)

Firefox Driver• Transport mechanism

� RPC

� HTTP

• Single or multiple end points� “REST-ish”

� SOAP (single end-point)

� REST (multiple end-points)

• Encoding data based on content type negotiation� HTML

� XML

� JSON

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Firefox Driver

Overview of the Firefox Driver Architecture

• HTTP server

� XPCOM by Selenium

� HTTPD by Mozilla

• Error handling(two level)

1. invalid request

2. failed commands

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ISSUE (6)

Internet Explorer Driver• Language to use for programming on Windows

� C# 4

� C++

• In order to get the Java classes communicating with the C++

� JNI (Java Native Interface)

� JNA (Java Native Architecture)

• Thread Boundary

� No

� Yes

Java is multi-thread and IE COMs have single thread. It is solved taking the IE instance in a separate thread and using the PostThreadMessage Win32 API to communicate across the thread boundary.

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IE Driver

IE Driver Architecture

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Who uses Selenium

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Future problems

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Demonstration of a driver

I hope to be on time!

Small Demo.

Driver:

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Reference

• The Architecture of Open

Source Application – Selenium

WebDriver – Simon Stewart

• Official Web site of Selenium

http://docs.seleniumhq.org/

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