HttpUnit Laboratorio di Sistemi Software - A.A. 2003/2004

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Laboratorio di Sistemi Software - A.A. 2003/2004

Introduction

HttpUnit, available from http://www.httpunit.org, is an open source Java library for programmatically interacting with HTTP servers.

HttpUnit provides an API for parsing HTML, submitting forms, following hyperlinks, setting cookies, and performing many other tasks normally associated with web browsers.

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Installing HttpUnit

Add httpunit.jar and Tidy.jar, both included with HttpUnit, to your classpath. Also ensure that an XML parser is installed.

httpunit.jar contains the class files for the HttpUnit application Tidy.jar is an open source tool for checking the syntax of

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“Agenda”

The recipes are presented in order as portions of a simple web application developed using a test-first approach.

If the web application were complete, it would allow users to subscribe and unsubscribe from a newsletter. It would also allow administrators to view the complete list of newsletter subscribers, but only after providing a username and

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Preparing for Test-First Development

Problem:

You want to configure your development environment to support test-first development with HttpUnit, JUnit, Tomcat, and Ant.

Solution:

Create an Ant buildfile to automatically build and deploy your web application. The buildfile allows you to quickly redeploy and test after each change to your code.

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Configuring Tomcat

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Configuring Ant

In order to test using Ant's junit task, you should copy

servlet.jar, httpunit.jar, junit.jar, and Tidy.jar to Ant's lib

directory. This makes it easy to ensure that all of the required JAR files are loaded using the same Java ClassLoader when you are running your tests.

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Classpath e compile targets

Define a classpath:

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Web Application aRchive target

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Tomcat deploy

Use Tomcat’s manager application:

http://localhost:8080/manager/install?path=/news&war=jar:file:/path/to/news.war!/ Or create a deploy target:

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Tomcat undeploy

Use Tomcat’s manager application: http://localhost:8080/manager/remove?path=/news Or create an undeploy target:

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JUnit target

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Following Hyperlinks (2)

Run the faulty test first, then write the servlet to generate a minimal subscribtion page (TDD

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Writing testable HTML

Problem:

You want to use HttpUnit to test your web application, but it can't parse your HTML.

Solution:

Write well-formed HTML, ensuring the tags are properly nested and attributes are quoted. For best results, write XHTML.

If you are encountering problems, call this method to turn on HTML Tidy warnings:

This causes HTML Tidy to print warning messages to the console, letting you know which lines of your HTML pages are incorrect.

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Testing HTML tables (2)

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Testing HTML tables (3)

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Testing HTML tables (4)

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Extending the servlet behavior

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Refactoring the Servlet

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Testing Elements on HTML Forms (1)

Check existence of buttons:

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Testing Elements on HTML Forms (2)

Check existence of input fields:

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Newsletter Subscription page

Note:

the HttpUnit tests are not verifying every aspect of page layout.

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Testing through a firewall

Set the proxySet, proxyHost, and proxyPort system properties.

¾ HttpUnit uses java.net.HttpURLConnection, which checks the proxySet system property to determine if it should operate through a proxy server.

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Testing cookies

Cookies are little pieces of information that web applications store on the client browser's machine.

¾ Cookies allow web sites to maintain state information as you view different web pages.

Use WebConversation's addCookie( ) method to create new cookies, and its getCookieValue( ) method to retrieve cookie values.

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Testing secure pages

You want to test a page that requires a username and password for login.

Simulate HTTP BASIC authentication using WebConversation's setAuthorization( ) method.

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Bibliography

Eric M. Burke & Brian M. Coyner

“Java Extreme Programming Cookbook” O’Reilly