- 1 Agile Software Development
- 1.1 The Fundamentals of Agile Software Development
- 1.2 Aspects of Agile Approaches
- 2 Fundamental Agile Testing Principles, Practices, and Processes
- 2.1 The Differences between Testing in Traditional and Agile Approaches
- 2.2 Status of Testing in Agile Projects
- 2.3 Role and Skills of a Tester in an Agile Team
- 3 Agile Testing Methods, Techniques, and Tools
- 3.1 Agile Testing Methods
- 3.2 Assessing Quality Risks and Estimating Test Effort
- 3.3 Techniques in Agile Projects
- 3.4 Tools in Agile Projects
Agile Software Development
Agile Manifesto, Agile software development, incremental development model, iterative development model, software lifecycle, test automation, test basis, test-driven development, test oracle, user story
The Fundamentals of Agile Software Development
A tester on an Agile project will work differently than one working on a traditional project. Testers must understand the values and principles that underpin Agile projects, and how testers are an integral part of a whole-team approach together with developers and business representatives. The members in an Agile project communicate with each other early and frequently, which helps with removing defects early and developing a quality product.
Agile Software Development and the Agile Manifesto
In 2001, a group of individuals, representing the most widely used lightweight software development methodologies, agreed on a common set of values and principles which became known as the Manifesto for Agile Software Development or the Agile Manifesto [Agilemanifesto]. The Agile Manifesto contains four statements of values:
- Individuals and interactions over processes and tools
- Working software over comprehensive documentation
- Customer collaboration over contract negotiation
- Responding to change over following a plan
The Agile Manifesto argues that although the concepts on the right have value, those on the left have greater value.
Individuals and Interactions
Agile development is very people-centered. Teams of people build software, and it is through continuous communication and interaction, rather than a reliance on tools or processes, that teams can work most effectively.
From a customer perspective, working software is much more useful and valuable than overly detailed documentation and it provides an opportunity to give the development team rapid feedback. In addition, because working software, albeit with reduced functionality, is available much earlier in the development lifecycle, Agile development can confer significant time-to-market advantage. Agile development is, therefore, especially useful in rapidly changing business environments where the problems and/or solutions are unclear or where the business wishes to innovate in new problem domains.
Customers often find great difficulty in specifying the system that they require. Collaborating directly with the customer improves the likelihood of understanding exactly what the customer requires. While having contracts with customers may be important, working in regular and close collaboration with them is likely to bring more success to the project.
Responding to Change
Change is inevitable in software projects. The environment in which the business operates, legislation, competitor activity, technology advances, and other factors can have major influences on the project and its objectives. These factors must be accommodated by the development process. As such, having flexibility in work practices to embrace change is more important than simply adhering rigidly to a plan.
The core Agile Manifesto values are captured in twelve principles:
- Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
- Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.
- Deliver working software frequently, at intervals of between a few weeks to a few months, with a preference to the shorter timescale.
- Business people and developers must work together daily throughout the project.
- Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.
- The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
- Working software is the primary measure of progress.
- Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.
- Continuous attention to technical excellence and good design enhances agility.
- Simplicity - the art of maximizing the amount of work not done—is essential.
- The best architectures, requirements, and designs emerge from self-organizing teams.
- At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.
The different Agile methodologies provide prescriptive practices to put these values and principles into action.
The whole-team approach means involving everyone with the knowledge and skills necessary to ensure project success. The team includes representatives from the customer and other business stakeholders who determine product features. The team should be relatively small; successful teams have been observed with as few as three people and as many as nine. Ideally, the whole team shares the same workspace, as co-location strongly facilitates communication and interaction. The whole team approach is supported through the daily stand-up meetings (see Section 2.2.1) involving all members of the team, where work progress is communicated and any impediments to progress are highlighted. The whole-team approach promotes more effective and efficient team dynamics.
The use of a whole-team approach to product development is one of the main benefits of Agile development. Its benefits include:
- Enhancing communication and collaboration within the team
- Enabling the various skill sets within the team to be leveraged to the benefit of the project
- Making quality everyone’s responsibility
The whole team is responsible for quality in Agile projects. The essence of the whole-team approach lies in the testers, developers, and the business representatives working together in every step of the development process. Testers will work closely with both developers and business representatives to ensure that the desired quality levels are achieved. This includes supporting and collaborating with business representatives to help them create suitable acceptance tests, working with developers to agree on the testing strategy, and deciding on test automation approaches. Testers can thus transfer and extend testing knowledge to other team members and influence the development of the product.
The whole team is involved in any consultations or meetings in which product features are presented, analyzed, or estimated. The concept of involving testers, developers, and business representatives in all feature discussions is known as the power of three [Crispin08].
Early and Frequent Feedback
Agile projects have short iterations enabling the project team to receive early and continuous feedback on product quality throughout the development lifecycle. One way to provide rapid feedback is by continuous integration (see Section 1.2.4).
When sequential development approaches are used, the customer often does not see the product until the project is nearly completed. At that point, it is often too late for the development team to effectively address any issues the customer may have. By getting frequent customer feedback as the project progresses, Agile teams can incorporate most new changes into the product development process. Early and frequent feedback helps the team focus on the features with the highest business value, or associated risk, and these are delivered to the customer first. It also helps manage the team better since the capability of the team is transparent to everyone. For example, how much work can we do in a sprint or iteration? What could help us go faster? What is preventing us from doing so?
The benefits of early and frequent feedback include:
- Avoiding requirements misunderstandings, which may not have been detected until later in the development cycle when they are more expensive to fix.
- Clarifying customer feature requests, making them available for customer use early. This way, the product better reflects what the customer wants.
- Discovering (via continuous integration), isolating, and resolving quality problems early.
- Providing information to the Agile team regarding its productivity and ability to deliver.
- Promoting consistent project momentum.
Aspects of Agile Approaches
Agile Software Development Approaches
Collaborative User Story Creation
Release and Iteration Planning
Fundamental Agile Testing Principles, Practices, and Processes
The Differences between Testing in Traditional and Agile Approaches
Testing and Development Activities
Project Work Products
Testing and Configuration Management
Organizational Options for Independent Testing
Status of Testing in Agile Projects
Communicating Test Status, Progress, and Product Quality
Managing Regression Risk with Evolving Manual and Automated Test Cases
Role and Skills of a Tester in an Agile Team
Agile Tester Skills
The Role of a Tester in an Agile Team
Agile Testing Methods, Techniques, and Tools
Agile Testing Methods
Test-Driven Development, Acceptance Test-Driven Development, and Behavior-Driven Development
The Test Pyramid
Testing Quadrants, Test Levels, and Testing Types
The Role of a Tester
Assessing Quality Risks and Estimating Test Effort
Assessing Quality Risks in Agile Projects
Estimating Testing Effort Based on Content and Risk
Techniques in Agile Projects
Acceptance Criteria, Adequate Coverage, and Other Information for Testing
Applying Acceptance Test-Driven Development
Functional and Non-Functional Black Box Test Design
Exploratory Testing and Agile Testing
Tools in Agile Projects
Task Management and Tracking Tools
Communication and Information Sharing Tools
Software Build and Distribution Tools
Configuration Management Tools
Test Design, Implementation, and Execution Tools
Cloud Computing and Virtualization Tools
Virtualization allows a single physical resource (server) to operate as many separate, smaller resources. When virtual machines or cloud instances are used, teams have a greater number of servers available to them for development and testing. This can help to avoid delays associated with waiting for physical servers. Provisioning a new server or restoring a server is more efficient with snapshot capabilities built into most virtualization tools. Some test management tools now utilize virtualization technologies to snapshot servers at the point when a fault is detected, allowing testers to share the snapshot with the developers investigating the fault.