What is Software Testing Methodologies?

What is Software Testing Methodologies?

In the field of Software testing we use different types of Software Testing Methodologies. In today’s Software Testing Class, we will see what all Software Testing Methodologies & software testing technique is used in the day today software testing life cycle.

In the Software Development Process different software development approaches are used. A software development process also known as a Software Development Life Cycle (SDLC).

Each process model has its own advantages & disadvantages, the choosing of model is based on the requirement & need of your project to do the success in process of software development.
Here are the few commonly used Software Development Life Cycle used in actual testing:

• Waterfall model
• V model
• Agile model
• Spiral model
• RUP
• RAD

1) Waterfall Model

The Waterfall Model approach is most basic life cycle model, which is the first Process Model begins and used broadly in Software Development to make sure project success. This model is developed by Winston Royce in the early 1970. Waterfall model is software development process sequential process, as flowing progressively downwards like waterfall via multiple phases & these simple sequence of phases has its own defines activities and goals. The Waterfall model is divided into following separate phases:

• Requirement Gathering & Analysis phase,
• Software Design,
• Implementation and Testing
• Maintenance

All these phases are the sequential phases & next step is totally depends on the previous step, so that second phase is begins as only if the defined set of objectives and goals are completed first.

The stages of “The Waterfall Model” are:

Requirement Gathering & Analysis:
This is the starting phase of the SDLC in which all possible system requirements are captured & analyzed. Software requirements specification includes the complete information about how actual end users are expecting from the system. This document covers all the necessary requirements for the development of project. Finally after completion of requirement gathering & analysis (validation of requirement against the user needs), a Requirement Specification document is created which give out as a input to the next phase of SDLC. In this model once we moved to the next phase then it won’t possible to add or update the requirements.

System & Software Design: Prior to start actual coding, it is mandatory to be aware of what all features we are going to implement & how it would look like? The requirement specifications document created in the first phase is used as the input to this phase & based on this the system design specifications would be prepared. In which all hardware & system requirements would be specified. The system design specifications document prepared in this phase is used as input for the Implementation & Testing phase model.

Implementation & Unit Testing: Upon getting the system design specifications document the actual coding would be started. Before starting the actual coding requirements are divided into the models/units. In the actual coding the initially develop the small programs called units. After implementing all units the integration would be started in the next phase. The developed unit’s model functionality is tested separately in this phase to check whether the unit models are meets the specified requirements & this individual model testing is called as Unit Testing.

Integration & System Testing: In the previous model the system requirements are divided into models & each model is developed & tested separately. In this phase all units are integrated & done the system testing to check whether the all models/units are integrated properly or not & the system as whole doing as mention as per the system requirement document, so we call this phase as the Integration & System Testing. Upon complete testing of software is done then actual Software is successfully send to customer.

Operations & Maintenance: This phase is the never ending phase of the Waterfall Model. The problems are comes in picture after Implementation & Unit Testing phase. The issues found after the implementation phase i.e. not found in the period of the development life cycle. Some of the issues are not catch after testing cycle done so those are implemented in the maintenance phase, so this phase is called as Operations & Maintenance phase.

Advantages and Disadvantages of Waterfall Model:

Advantages of Waterfall Model:

• This is linear simple model to implement & easy to maintain.
• In the SDLC initial phase spent time on reviewing requirements and design which saves the time later.
• Required resources are minimum in this model as compare to other.
• After every phase of the model a document in created which help & simpler to understand & design the system.
• Upon completion of coding, is done to check for implemented code or correctness of system.
•  For each stage deadlines can be set which will help to develop the system on decided time frame.

Disadvantages of Waterfall Model: 

• The biggest disadvantages of such system is it won’t allow to go back. If the problems in the design phase which creates complication in the implementation phase.
• This model is rigid model. Not flexible & make changes is not possible in the development of system.
• Unable to start the next phase before completing the previous phase so time consuming.
• In the deployment phase all requirements are not covered or all requirements are not cover so adding such requirements may create unsuitable system.
• To make it customer happy such new requirement need to be implemented in new version of system which leads to added cost to system development.

2) V Model

In the basic Waterfall model process seen some disadvantages or limitations in the model which started a new SDLC model. As we seen in the Waterfall model the issues found in the end of the SDLC, this is due to the testing is occurred in the end phases of the you SDLC. To overcome this problem the V-Model is comes into the picture. It is always better to introduce testing in the early phase of SDLC, as in this model the testing activity gets started from the early phase of the SDLC.

Before starting the actual testing, testing team has to work on various activities like preparation of Test Strategy, Test Planning, Creation of Test cases & Test Scripts which is work parallel with the development activity which help to get the test deliverable on time.

V Model – Software Development Life Cycle

• V Model - Software Development Life Cycle
• In the V Model Software Development Life Cycle, based on same information(requirement specification document) the development & testing activity is started. Based on the requirement document developer team started working on the design & after completion on design start actual implementation and testing team starts working on test planning, test case writing, test scripting. Both activities are working parallel to each other. In Waterfall model & V-model they are quite similar to each other. As it is most popular Software Testing Life Cycle model so most of the organization is following this model.
• The V-model is also called as Verification and Validation model. The testing activity is perform in the each phase of Software Testing Life Cycle phase. In the first half of the model validations testing activity is integrated in each phase like review user requirements, System Design document & in the next half the Verification testing activity is come in picture.
• Typical V-model shows Software Development activities on the Left hand side of model and the Right hand side of the model actual Testing Phases can be performed.
• In this process “Do-Procedure” would be followed by the developer team and the “Check-Procedure” would be followed by the testing team to meets the mentioned requirements.
• In the V-Model software development life cycle different steps are followed however here we will taking a most common type of V-model example. The V-model typically consist of the following phases:
• 1. Unit Testing: Preparation of Unit Test Cases
  2. Integration Testing: Preparation of Integration Test Cases
  3. System Testing: Preparation of System test cases
  4. Acceptance Testing: Preparation of Acceptance Test Cases

What is Agile model – advantages, disadvantages and when to use it?

Agile development model is also a type of Incremental model. Software is developed in incremental, rapid cycles. This results in small incremental releases with each release building on previous functionality. Each release is thoroughly tested to ensure software quality is maintained. It is used for time critical applications.  Extreme Programming (XP) is currently one of the most well known agile development life cycle model.

Diagram of Agile model:

Advantages of Agile model:

• Customer satisfaction by rapid, continuous delivery of useful software.
• People and interactions are emphasized rather than process and tools. Customers, developers and testers constantly interact with each other.
• Working software is delivered frequently (weeks rather than months).
• Face-to-face conversation is the best form of communication.
• Close, daily cooperation between business people and developers.
• Continuous attention to technical excellence and good design.
• Regular adaptation to changing circumstances.
• Even late changes in requirements are welcomed

Disadvantages of Agile model:

• In case of some software deliverables, especially the large ones, it is difficult to assess the effort required at the beginning of the software development life cycle.
• There is lack of emphasis on necessary designing and documentation.
• The project can easily get taken off track if the customer representative is not clear what final outcome that they want.
• Only senior programmers are capable of taking the kind of decisions required during the development process. Hence it has no place for newbie programmers, unless combined with experienced resources.

When to use Agile model:

• When new changes are needed to be implemented. The freedom agile gives to change is very important. New changes can be implemented at very little cost because of the frequency of new increments that are produced.
• To implement a new feature the developers need to lose only the work of a few days, or even only hours, to roll back and implement it.
• Unlike the waterfall model in agile model very limited planning is required to get started with the project. Agile assumes that the end users’ needs are ever changing in a dynamic business and IT world. Changes can be discussed and features can be newly effected or removed based on feedback. This effectively gives the customer the finished system they want or need.
• Both system developers and stakeholders alike, find they also get more freedom of time and options than if the software was developed in a more rigid sequential way. Having options gives them the ability to leave important decisions until more or better data or even entire hosting programs are available; meaning the project can continue to move forward without fear of reaching a sudden standstill.