Tuesday, 21 May 2013

Non-Functional Testing - Performance, Usability, Security, Portability

Non-Functional Testing

  • Performance Testing

    • Load Testing
    • Stress Testing

  • Usability Testing

    • UI VS Usability Testing

  • Security Testing

  • Portability Testing

Non-Functional Testing definition :

This section is based upon the testing of the application from its non-functional attributes. Non-functional testing of Software involves testing the Software from the requirements which are non functional in nature related but important a well such as performance, security, user interface etc.

  • Performance Testing
    • Load Testing
    • Stress Testing
  • Usability Testing
    • UI VS Usability Testing
  • Security Testing
  • Portability Testing
Some of the important and commonly used non-functional testing types are mentioned as follows:

Performance Testing

It is mostly used to identify any bottlenecks or performance issues rather than finding the bugs in software. There are different causes which contribute in lowering the performance of software:
  • Network delay.
  • Client side processing.
  • Database transaction processing.
  • Load balancing between servers.
  • Data rendering.
Performance testing is considered as one of the important and mandatory testing type in terms of following aspects:
  • Speed (i.e. Response Time, data rendering and accessing)
  • Capacity
  • Stability
  • Scalability
It can be either qualitative or quantitative testing activity and can be divided into different sub types such as Load testing and Stress testing.

Load Testing

  • A process of testing the behavior of the Software by applying maximum load in terms of Software accessing and manipulating large input data. It can be done at both normal and peak load conditions. This type of testing identifies the maximum capacity of Software and its behavior at peak time.
  • Most of the time, Load testing is performed with the help of automated tools such as Load Runner, AppLoader, IBM Rational Performance Tester, Apache JMeter, Silk Performer, Visual Studio Load Test etc.
  • Virtual users (VUsers) are defined in the automated testing tool and the script is executed to verify the Load testing for the Software. The quantity of users can be increased or decreased concurrently or incrementally based upon the requirements.

Stress Testing

  • This testing type includes the testing of Software behavior under abnormal conditions. Taking away the resources, applying load beyond the actual load limit is Stress testing.
  • The main intent is to test the Software by applying the load to the system and taking over the resources used by the Software to identify the breaking point. This testing can be performed by testing different scenarios such as:
    • Shutdown or restart of Network ports randomly.
    • Turning the database on or off.
    • Running different processes that consume resources such as CPU, Memory, server etc.

Usability Testing

This section includes different concepts and definitions of Usability testing from Software point of view. It is a black box technique and is used to identify any error(s) and improvements in the Software by observing the users through their usage and operation.

According to Nielsen, Usability can be defined in terms of five factors i.e. Efficiency of use, Learn-ability, Memor-ability, Errors/safety, satisfaction. According to him the usability of the product will be good and the system is usable if it possesses the above factors.

Nigel Bevan and Macleod considered that Usability is the quality requirement which can be measured as the outcome of interactions with a computer system. This requirement can be fulfilled and the end user will be satisfied if the intended goals are achieved effectively with the use of proper resources.

Molich in 2000 stated that user friendly system should fulfill the following five goals i.e. Easy to Learn, Easy to Remember, Efficient to Use, Satisfactory to Use and Easy to Understand.

In addition to different definitions of usability, there are some standards and quality models and methods which define the usability in the form of attributes and sub attributes such as ISO-9126, ISO-9241-11, ISO-13407 and IEEE std.610.12 etc.

  • UI VS Usability Testing

UI testing involves the testing of Graphical User Interface of the Software. This testing ensures that the GUI should be according to requirements in terms of color, alignment, size and other properties.

On the other hand Usability testing ensures that a good and user friendly GUI is designed and is easy to use for the end user. UI testing can be considered as a sub part of Usability testing.

Security Testing

Security testing involves the testing of Software in order to identify any flaws ad gaps from security and vulnerability point of view. Following are the main aspects which Security testing should ensure:
  • Confidentiality.
  • Integrity.
  • Authentication.
  • Availability.
  • Authorization.
  • Non-repudiation.
  • Software is secure against known and unknown vulnerabilities.
  • Software data is secure.
  • Software is according to all security regulations.
  • Input checking and validation.
  • SQL insertion attacks.
  • Injection flaws.
  • Session management issues.
  • Cross-site scripting attacks.
  • Buffer overflows vulnerabilities.
  • Directory traversal attacks.

Portability Testing

Portability testing includes the testing of Software with intend that it should be re-useable and can be moved from another Software as well. Following are the strategies that can be used for Portability testing.
  • Transferred installed Software from one computer to another.
  • Building executable (.exe) to run the Software on different platforms.
Portability testing can be considered as one of the sub parts of System testing, as this testing type includes the overall testing of Software with respect to its usage over different environments. Computer Hardware, Operating Systems and Browsers are the major focus of Portability testing. Following are some pre-conditions for Portability testing:
  • Software should be designed and coded, keeping in mind Portability Requirements.
  • Unit testing has been performed on the associated components.
  • Integration testing has been performed.
  • Test environment has been established.


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