Scripting Techniques in Test Automation

From easy techniques as record and playback to more advanced techniques like keyword driven testing we have numerous options as far as test automation is concern. The test manager has to choose wisely the technique to minimize the cost for development and maintenance. The various test automation techniques are as follows.

   1.      Linear
   2.      Structured
   3.      Shared
   4.      Data Driven
   5.      Keyword driven


Linear Scripting

Linear scripting approach is simple record and playback approach of test automation. It can contain some redundant functions etc which may not be required at times.

Pros And cons of Leaner Scripting.

   1.      A non-structured way of programming.
   2.      Very low development cost.
   3.      Programming skills required is negligible.
   4.      No planning required.
   5.      Data is hard coded in the script.
   6.      Maintenance cost is high.
   7.      No sharing of scripts done so efforts are often repeated.

Structured Programming

Structured programming uses control structures in the scripts so testers can control the flow of the test script. The control structures used are 'if- else', 'for', 'while', 'select-case' statements which help in implementing decision making in the script, making some tasks iteratively.


Pros and cons of Structured Programming

   1.      A structured approach of scripting.
   2.      Dev elopement cost is relatively higher then leaner programming.
   3.      Intermediate programming skills are required.
   4.      To some extent planning is required.
   5.      Data is hard coded in the script.
   6.      Maintenance cost is relatively low comparing to linear programming.
   7.      Since control structures are used so scripting efforts increases to some extent.

Shared/Modular Scripting

In this technique the scripts representing a application behavior is shared with other scripts. This means the AUT common functionality is scripted as shared scripts and will be called by other scripts to complete the test cases. So the re-usability factor is very high. This makes the scripts modular in terms of common functionality. Such scripts sometimes can be used for other applications as well.


Pros and cons of Shared Programming.

   1.      Scripts are more structured then the structured approach of programming.
   2.      Development costs are reduced relative to structured scripting since the effort duplication is reduced.
   3.      Intermediate programming skills are required.
   4.      More planning is needed comparing to structured programming.
   5.      Data is hard coded in scripts.
   6.      Maintenance cost is lower than linear programming.

Data Driven Scripting

This technique separates data from the scripts and stores the data in external repository in the form of files. So the script just contains the programmed code not the data. This useful when the data changes over time and cycle. Script need not be changed for change in data.


Pros and Cons of Data Driven Scripting

   1.      Scripts are programmed in a structured manner.
   2.      Development cost is relatively high because of parametrization.
   3.      High programming skills are required.
   4.     More planning is needed.
   5.      Data is isolated in data tables or external files.
   6.      Script maintenance is low.
   7.      Recommended to be used where positive and negative testing both are involved.

Keyword Driven Scripting
In this approach the control to check and execute operations are mentained with exernal data files. So the test data and the operations of the test is planned in external data files. Extra library is needed to interpret this data in addition to the conventional script. Its an extension of data driven testing.

Pros and Cons of Keyword Driven Scripting.

   1.      it combines the data driven, shared and structured programming techniques.
   2.      Development cost high since testing planning effort is high.
   3.      High programming skills are required by tester.
   4.      Initial planning cost is high.
   5.      Data exists in the external files.
   6.      Maintenance cost is very low.
   7.      Extra framework and library is needed and hence more programming skills is required.

This is my piece of understanding about various types of test automation scripting methodology. I am open for your comments to enhance it make it more meaningful .Please provide your valuable feedback.

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