Wednesday, 3 July 2013

Cross Browser Testing - Basics - Learner's Series - 4

Browser Selection

To shortlist browsers & their OS versions, we can consider a combination of data from

  • Browser Trend Analysis
  • Technical analysis to remove browser redundancy
  • Risk Based Browser/OS matrix


Output of Browser Trend Analysis can be used to analyze the similarities between different browsers based on

·         Layout Engine
·         Shell Features
·         JavaScript engine
·         Plug-ins

Different browser versions can be grouped and few of them can be considered for the execution scope, based on the risk attributes of the browser/OS combination & prioritizing them.

Risk Based OS – Browser Priority

To identify each of the supported browser’s priority,

Priority = (probability of the Bug occurring) x (Expected loss)

Probability of the Bug

Variety of factors has to be considered for estimating the “probability” of a bug being discovered in a website while using a particular browser.

·        Age of the Browser
Age of the browser is meant, when the most stable browser version was released to the market/users. Ex: - IE 6.0 is released in 2001 and is the default browser shipped with Windows XP, which used to have a large market share.  Probability of Bug in an IE 6.x version is higher, due to the lack of compatibility with modern web standards.
·         Default Browser used by the Dev Team(Example – Firefox 3.6.x)
·         Similarities between Default(Example – Firefox 3.6.x) & the Targeted browsers(Example – Firefox 3.6.y, Safari 5)

Expected Loss

Estimating the “expected loss” can be found out by the popularity of a browser on which the app is mostly run (No. of users & Type of usage) and the stability of the browser with respect to the client technologies used.
An application can be used by users who are Internal/External/Both. 

This type of usage along with the probable number of users who access the application decides the impact of the browser /OS version (Expected Loss)

The analysis ((probability of the Bug occurring) x (expected loss)) will result in the identification of priority as “high”, “medium” and “low” categories for a particular application.

Browser**
Probability of Bug
Expected Loss
Priority
IE 6
High
Low
Low
IE 7
High
Medium
High
IE 8
Medium
High
High
IE 9
Medium
Medium
Medium
Firefox 3.x
Low
Medium
Low*
Firefox 4.x
Low
Low
Low*
Firefox 5.x+
Low
High
Low
Firefox 11
Medium
Medium
Medium
Firefox 12
Medium
Medium
Medium
Apple Safari  5
Medium
Medium
Medium
Google Chrome 12
Low
Medium
Low*
Google Chrome 13+
Low
High
Low
Google Chrome 18
Low
High
Low

Low* - Low Priority/Importance browser.
** - For the above analysis, Microsoft Windows OS is considered & new versions of Browser/OS/devices might have been released by now.+ - Since Firefox & Google Chrome browser versions are getting iterated fast, Test coverage is recommended for the latest major, stable version of the browser & analytics data from your web application.

All the credits for this post go to,

Matt Archer - mattarcherblog.wordpress.com
Brent Strange - http://QAInsight.net

as I have just collated the information from their sites, to give a basic idea on browser selection.

Both of them have posted detailed & more analyzed information on Cross Browser Testing.

For info on, Risk Based, Cross Browser Testing with Scrum, Please refer

For info on, various browser’s technology background, Please refer

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