Role of a tester in Defect Prevention

“What is the role of a tester in Defect Prevention and Defect Detection?”. In this post we will discuss the role of a tester in these phases and how to testers can prevent more defects in Defect Prevention phase and how testers can detect more bugs in Defect Detection phase
Role of a tester in defect prevention and defect detection.
Defect prevention – In Defect prevention, developers plays an important role. In this phase Developers do activities like – code reviews/static code analysis, unit testing, etc. Testers are also involved in defect prevention by reviewing specification documents. Studying the specification document is an art.
While studying specification documents, testers encounter various queries. And many times it happens that with those queries, requirement document gets changed/updated.
Developers often neglect primary ambiguities in specification documents in order to complete the project; or they fail to identify them when they see them. Those ambiguities are then built into the code and represent a bug when compared to the end-user's needs. This is how testers help in defect prevention. 

What is Black Box Testing

Black Box Testing is testing without knowledge of the internal workings of the item being tested. For example, when black box testing is applied to software engineering, the tester would only know the “legal” inputs and what the expected outputs should be, but not how the program actually arrives at those outputs.

It is because of this that black box testing can be considered testing with respect to the specifications, no other knowledge of the program is necessary. For this reason, the tester and the programmer can be independent of one another, avoiding programmer bias toward his own work. For this testing, test groups are often used, “Test groups are sometimes called professional idiots…people who are good at designing incorrect data.” 1 Also, do to the nature of black box testing, the test planning can begin as soon as the specifications are written. The opposite of this would be glass box testing, where test data are derived from direct examination of the code to be tested. For glass box testing, the test cases cannot be determined until the code has actually been written. Both of these testing techniques have advantages and disadvantages, but when combined, they help to ensure thorough testing of the product.

Waterfall Model

Waterfall Model is the most common method used in software testing. It is said to be a water fall method because it is like flowing downwards steadily from step to step.
The main phase or steps in the water fall method are

Conception,
Initiation,
Analysis,
Design,
Construction,
Testing,
Production/Implementation,
Maintenance.
This water fall method actually originated in the manufacturing and construction industries. At that time since no software methodologies existed, this was taken to the software development and testing. the main highlight of this method is one can go to the next step of the development only after completing the on going step.

waterfall testing

Also the developers can go only to one step behind that is the immediately previous phase only. in this method, each phase of the development activity is followed by verification and validation activities. in the waterfall method, the following are the steps involved. you can move on to the next step only when you finishes the present one. the phases or steps are:

Software requirement specification
System and sotware design
Implementation (coding or unit testing)
Integration
Testing and validation
Operation or installation
Maintenance

What is Beta Testing

What is Beta Testing

In this type of testing, the software is distributed as a beta version to the users and users test the application at their sites. As the users explore the software, in case if any exception/defect occurs that is reported to the developers. Beta testing comes after alpha testing. Versions of the software, known as beta versions, are released to a limited audience outside of the company. View the advantages of beta testing


beta-testing

The software is released to groups of people so that further testing can ensure the product has few faults or bugs. Sometimes, beta versions are made available to the open public to increase the feedback field to a maximal number of future users.

What is ALPHA TESTING

In this type of testing, the users are invited at the development center where they use the application and the developers note every particular input or action carried out by the user. Any type of abnormal behavior of the system is noted and rectified by the developers.

Alpha testing is done before the beta testing and after the acceptance testing. Mostly its done by the in-house members from developers and qa teams. I simple words its the testing by developed team just before launching the live beta version of that software.

What is User Acceptance Testing

In this type of testing, the software is handed over to the user in order to find out if the software meets the user expectations and works as it is expected to. In software development, user acceptance testing (UAT) – also called beta testing, application testing, and end user testing – is a phase of software development in which the software is tested in the “real world” by the intended audience.



User Acceptance Testing can be done by in-house testing in which volunteers or paid test subjects use the software or, more typically for widely-distributed software, by making the test version available for downloading and free trial over the Web. The experiences of the early users are forwarded back to the developers who make final changes before releasing the software commercially.

What is Regression Testing

Regression testing is a style of testing that focuses on retesting after changes are made. In traditional regression testing, we reuse the same tests (the regression tests). In risk-oriented regression testing, we test the same areas as before, but we use different (increasingly complex) tests. Traditional regression tests are often partially automated. These note focus on traditional regression.