Agile refers to something that is quick or adaptable. A software development approach based on iterative development is referred to as an “agile process model.” Agile approaches divide projects into smaller iterations or sections and avoid long-term planning. The scope and requirements of the project are defined at the start of the development phase. The number of iterations, duration, and scope of each iteration are all clearly determined ahead of time.

In the Agile process model, each iteration is a small-time “frame” that lasts anywhere from one to four weeks. The segmentation of the complete project into smaller pieces helps to reduce the total project delivery time requirements while minimising project risk. Before a working product is demonstrated to the client, each iteration requires a team to go through the entire software development life cycle, which includes planning, requirements analysis, design, coding, and testing.

Agile Model Phases

The Agile model is divided into phases, which are as follows: 

• Gathering requirements 
• Create the specifications 
• Iteration/construction 
• Quality assurance/testing 
• Deployment 
• Feedback

1. Gathering Needs

The requirements must be defined in this step. You should describe the project’s business opportunities and estimate the time and effort required to complete it. You can assess technical and economic feasibility based on this information. 

2. Determine the needs 

Once the project has been defined, collaborate with stakeholders to define the requirements. To demonstrate how new features function and how they will fit into your existing system, use a user flow diagram or a high-level UML diagram. 

3. Construction/iteration

Work begins once the team has defined the requirements. Designers and developers begin work on their projects, with the goal of releasing a functional product. The product will go through several stages of development before being released, thus it will have basic, rudimentary functionality.

4. Testing 

The Quality Assurance team checks the product’s performance and looks for bugs during this step. 

5. Deployment

The team issues a product for the user’s work environment in this step. 

6. Feedback

After the product has been released, the final step is to get feedback. This is where the team receives feedback on the product and works through it.

Agile Testing Methods

• Scrum
• Crystal
• Dynamic Software Development Method(DSDM)
• Feature Driven Development(FDD)
• Lean Software Development
• eXtreme Programming(XP)

Scrum 

Scrum is an agile development process that focuses on task management in team-based development environments. 

There are three positions in it, each with its own set of responsibilities: 

• Scrum Master: The scrum master can assemble the master team, schedule meetings, and remove impediments to the process. 
• Product owner: The product owner creates the product backlog, prioritises the delay, and is in charge of the functionality distribution on each repeat. 
• Scrum Team: The team organises and manages its work in order to complete the sprint or cycle.

eXtreme Programming

When customers’ expectations or requirements are continually changing, or when they are unsure of the system’s performance, this practice is utilised. 

Crystal 

This approach is divided into three concepts: 

• Chartering: This phase includes a variety of activities such as assembling a development team, conducting feasibility analyses, developing plans, and so on. 
• Cyclic delivery: this entails two more cycles, which are as follows: 
  • The release strategy has been updated by the team. 
  • The users are served through an integrated product. 
• Wrap-up: This phase performs deployment and post-deployment, depending on the user environment.

Dynamic Software Development Method(DSDM)

DSDM is a software development rapid application development technique that provides an agile project distribution structure. Users must be actively connected in order to use DSDM, and teams have been given the authority to make decisions. DSDM employs the following techniques: 

• Time Boxing
• MoSCoW Rules
• Prototyping

FDD (Feature-Driven Development) 

The “Designing and Building” features are the centre of this method. Unlike other smart approaches, FDD outlines the small work steps that must be obtained separately for each function. 

Lean Software Development

The notion of “just in time production” underpins the lean software development process. The lean method refers to accelerating software development while lowering costs. The seven phases of lean development can be characterised as follows: 

• Eliminating Waste
• Amplifying learning
• Defer commitment (deciding as late as possible)
• Early delivery
• Empowering the team
• Building Integrity
• Optimize the whole

When Should the Agile Model Be Used? 

• When there are a lot of changes to be made. 
• When you have access to a highly qualified and experienced workforce. 
• When a customer is ready to meet with a software team on a regular basis. 
• When the scope of the endeavour is limited.

Agile Method Benefits (Pros)

• Continual Delivery 
• Communication with clients on a one-on-one basis. 
• Design that is both efficient and meets the needs of the company. 
• Changes can be made at any moment. 
• It cuts down on overall development time. 

Agile Model Disadvantages (Cons)

• Due to a lack of formal records, there is a misunderstanding, and important decisions made at various stages can be misconstrued by different team members at any time. 
• Maintenance of the completed project can become challenging due to a lack of sufficient documentation once the project is completed and the developers are assigned to another project.