Evaluation and testing

Evaluation and testing

1WUCM1

Testing large websites

• Testing should be against agreed requirements

• For large sites with dynamic pages (Java, ASP, Perl, etc.):– Use a development environment such as

NetBeans, DreamWeaver or Visual Studio– Offers debugging services, break points, traces,

variable contents, spying, etc. – Permits remote debugging

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Testing small websites• Start with fully specified checklist

of expected functionality• Greenberg (1999) gives a good

example.

[] 1. Main page loads without errors

[ ] 2. Banner frame loads banner[ ] 3. Hover functionality over each of

the banner links[ ] 4. “About” is a link to about.htm[ ] 5. “Feedback” is a link to

feedback.htm[ ] 6. “Advertise” is a link to ad.htm[ ] 7. “Awards” is a link to

awards.htm[ ] 8. “Rings” is a link to rings.htmetc.

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Browser compatibility tests• Important to test your website using a variety of

browsers– cannot assume it will look/operate the same in all

• Use a range of different browsers and browser versions• Browsers you do not have, e.g. for a Mac? (

www.danvine.com/icapture) shows the ‘look’• Some tools permit you to exercise a range of browsers

– e.g. see the compatibility viewer http://www.delorie.com/web/wpbcv.html

• How do you record your test results? • Very least is a tick in the box, as above

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Web server tests

• Most tests presume the error is in the HTML, ASP, Perl, JavaScript etc.

• Possible that there are faults in the web server configuration

• How to modify site test plan to investigate the server environment?

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Link tracking and checking 1

• Tests should involve the link integrity of the web structure

• Web development systems (e.g. DreamWeaver) usually include a Link Checking option

• Link checking:– Validates your structure– Highlights broken links– Identifies orphan files – Lists external links

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DreamWeaver example

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Link tracking and checking 2

• Employ a 'web weeder' to check for:– Out of date links – Out of date documents

• Check external links:– Tedious to do manually– Automated tools make this chore easier– See the Web Design Group's links page

http://www.htmlhelp.com/links/validators.htm

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Link checking tools 1

• Options for installation:– On your web server– On the service provider’s server– On your development machine

• Examples of external services:– The fee based WebAlarm system

• http://www.linkalarm.com/– NetMechanic

• http://www.netmechanic.com/

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Examples

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Link checking tools 2

• Example – download link checker:– Xenu’s Link Sleuth

• http://home.snafu.de/tilman/xenulink.html• Someone needs to react to the Link Check

report:– Updating links if the service has moved– Rewriting the pages if the target has been retired– Advising users of problems in the past, so at least

your users are forewarned

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Link checking tools 3

• Users who tried to use your broken links– Use a tool to identify them – 404 errors– Contact them (if identifiable)

• might be good PR?

– WatchFire used to offer a range of white papers• http://www.watchfire.com/

– Check on Google

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Use of log files

• Some common log file formats:– Common– Referrer– Agent

• User defined possible:– Would need you to produce your own analysis

software– Seldom worth the trouble

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Log files 1

• Text in the format string not a place holder; is just sent as plain text

• Placeholders are replaced with their data– LogFormat "Host=%h URL=%U Server=%V Port=%p”

• Log files can be useful to look through, but you will need help

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Log files 2

• Simplest use is to just filter and display the most recent entries – – suitable for a human to monitor

• Benefits of visual inspection:– Check that pages deliverable (no 404 errors)– Check that security is working properly– Check that CGI is working properly– …

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Session logs 1

• Logs that track a single user session– What pages were viewed?– What order were the pages viewed in?– Was a purchase made (or some other goal

reached)?– Was enquiry abandoned?

• Not easy to achieve as web inherently “stateless” – each page is a new transaction!

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Session logs 2

• Techniques – see Nobles (2001):– Cookies – using cookies to capture and log session

data– Database-driven pages – using the code to capture

session data– Parsing server logs [next slide]– Web bugs – hidden <img> tagged files that trigger

unseen activity at the server– often 1 pixel square

– Non-covert <img> tracking – the more polite version of web bugs

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Log file analysis tools

• Many tools available – try a Google search• Analog (free from http://www.analog.cx) is

typical – see Wainwright or Nobles• Analog system is configured with a .cfg file

much like Apache’s• Some examples from the website

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Analog examples 1

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Analog examples 2

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Analog examples 3

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Analog examples 4

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Webalizer example 1

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Webalizer example 2

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Uses of log file analysis

• Qualitative checks:– identify (and then eliminate) any 404 file not

found log entries• Nobles (2001) lists a number of "quantitative"

uses:– How many page views is your site getting per day? – How many user sessions is your site getting per

day? – How long are users staying on your pages?

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More uses

– Which pages of your site are requested the most? – Which pages are requested the least? – What are the top ENTRY pages for your site? – What are your top EXIT pages? – Which pages are being viewed by themselves,

where visitors are not even clicking to go to another page?

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Even more uses

– Are visitors from other countries visiting your site? – Which sites are sending you the most visitors? – What are your top-referring search engines? – Which keywords are searchers using to find your

site? – How many of your visitors are using older

browsers? – Which search engine spiders have visited your site

recently?

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Web usage statistics

• Web statistics suffer from a number of problems:– Caching and proxy servers hide activity– Some users hide behind “anonymising” services– Most web pages built from very many small files –

how to count?

• Distinction between pages and hits

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Load testing

• Need a feel for the behaviour of your web server under different levels of load

• A baseline measurement is vital for:– planning for growth– identifying and dealing with DoS attacks

• Tools include:– Mercury Interactive’s Loadrunner – RSW Software’s E-Load – Segue Software’s Silkperformer

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Evaluation

• Checking to see if the website can be used effectively by its intended audience

• Evaluation in most cases will involve a human in the loop

• For a good technical set of examples see Spool, (1999)

• Not the main focus for WUCM1

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Search engines/directories

• How will search engines and directory services interact with your site?

• Nobles (2001) considers the matter from a number of perspectives, e.g.:– Key words and interaction with spiders or robots– Optimising your site to facilitate search engine

spiders• Deprecated features of HTML

– Web directories and how to get included

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Validation services 1

• Validators can for example check for a number of different features, including: – How usable are your pages to people with

disabilities– Conformance to the HTML specification (World

Wide Web Consortium - W3C.)

• See The Web Design Group list of links to different validation services– http://www.htmlhelp.com/links/validators.htm

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Validation services 2

• Generally two ways of using a validation service: – Submit your page to the validation service website

and receive back a report page– Mount a copy of the validation software on your

development system, and run your pages through this system

• Like virus checkers, web validators need regular updates

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Validation services 3

• Two important validation services are:– The W3C HTML conformance validation

• http://validator.w3.org/

– The accessibility validation services• http://www.cast.org/bobby/

– If you pass you get a logo, e.g.

• Review access to 1000 commercial websites– http://www.drc-gb.org/publicationsandreports/2.pdf

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