Software Testing has gained a phenomenal importance in the recent years in the System Development Life Cycle. Many learned people have worked on the topic and provided various techniques and methodologies for effective and efficient testing. Today, even though we have many books and articles on Software Test Engineering, many people are fallacious in understanding the underlying concepts of the subject.
Software Testing Guide Book (STGB) is an open source project aimed at bringing the technicalities of Software Testing into one place and arriving at a common understanding.
A brief history of Software engineering and the SDLC.
The software industry has evolved through 4 eras, 50’s –60’s, mid 60’s –late 70’s, mid 70’s- mid 80’s, and mid 80’s-present. Each era has its own distinctive characteristics, but over the years the software’s have increased in size and complexity. Several problems are common to almost all of the eras and are discussed below.
The Software Crisis dates back to the 1960’s when the primary reasons for this situation were less than acceptable software engineering practices. In the early stages of software there was a lot of interest in computers, a lot of code written but no established standards. Then in early 70’s a lot of computer programs started failing and people lost confidence and thus an industry crisis was declared. Various reasons leading to the crisis included:
q Hardware advances outpacing the ability to build software for this hardware.
q The ability to build in pace with the demands.
q Increasing dependency on software’s
q Struggle to build reliable and high quality software
q Poor design and inadequate resources.
This crisis though identified in the early years, exists to date and we have examples of software failures around the world. Software is basically considered a failure if the project is terminated because of costs or overrun schedules, if the project has experienced overruns in excess of 50% of the original or if the software results in client lawsuits. Some examples of failures include failure of Air traffic control systems, failure of medical software, and failure in telecommunication software. The primary reason for these failures other than those mentioned above is due to bad software engineering practices adopted. Some of the worst software practices include:
q No historical software-measurement data.
q Rejection of accurate cost estimates.
q Failure to use automated estimating and planning tools.
q Excessive, irrational schedule pressure and creep in user requirements.
q Failure to monitor progress and to perform risk management.
q Failure to use design reviews and code inspections.
To avoid these failures and thus improve the record, what is needed is a better understanding of the process, better estimation techniques for cost time and quality measures. But the question is, what is a process? Process transform inputs to outputs i.e. a product. A software process is a set of activities, methods and practices involving transformation that people use to develop and maintain software.
At present a large number of problems exist due to a chaotic software process and the occasional success depends on individual efforts. Therefore to be able to deliver successful software projects, a focus on the process is essential since a focus on the product alone is likely to miss the scalability issues, and improvements in the existing system. This focus would help in the predictability of outcomes, project trends, and project characteristics.
The process that has been defined and adopted needs to be managed well and thus process management comes into play. Process management is concerned with the knowledge and management of the software process, its technical aspects and also ensures that the processes are being followed as expected and improvements are shown.
From this we conclude that a set of defined processes can possibly save us from software project failures. But it is nonetheless important to note that the process alone cannot help us avoid all the problems, because with varying circumstances the need varies and the process has to be adaptive to these varying needs. Importance needs to be given to the human aspect of software development since that alone can have a lot of impact on the results, and effective cost and time estimations may go totally waste if the human resources are not planned and managed effectively. Secondly, the reasons mentioned related to the software engineering principles may be resolved when the needs are correctly identified. Correct identification would then make it easier to identify the best practices that can be applied because one process that might be suitable for one organization may not be most suitable for another.
Therefore to make a successful product a combination of Process and Technicalities will be required under the umbrella of a well-defined process.
Having talked about the Software process overall, it is important to identify and relate the role software testing plays not only in producing quality software but also maneuvering the overall process.
The computer society defines testing as follows: “Testing -- A verification method that applies a controlled set of conditions and stimuli for the purpose of finding errors. This is the most desirable method of verifying the functional and performance requirements. Test results are documented proof that requirements were met and can be repeated. The resulting data can be reviewed by all concerned for confirmation of capabilities.”
There may be many definitions of software testing and many which appeal to us from time to time, but its best to start by defining testing and then move on depending on the requirements or needs.
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