Executable Specifications with Scrum: A Practical Guide to Agile Requirements Discovery

Most books about specifications still assume that requirements can be known up front and won’t change much during your project. In today’s “real world,” however, you must specify and build software in the face of high and continuing uncertainty. Scrum and other agile methods have evolved to reflect this reality. Now, there’s a complete guide to specifying software in agile environments when prerequisites are unclear, requirements are difficult to grasp, and anything about your project could change. Long-time agile coach and enterprise architect Mario Cardinal shows how to create executable specifications and use them to test software behavior against requirements. Cardinal shows how to trawl requirements incrementally, step-by-step, using a vision-centric and emergent iterative practice that is designed for agility. Writing for analysts, architects, developers, and managers, Cardinal makes a strong case for the iterative discovery of requirements. Then, he moves from theory to practice, fully explaining the technical mechanisms and empirical techniques you need to gain full value from executable specifications. You’ll learn to connect specifications with software under construction, link requirements to architecture, and automate requirements verification within the Scrum framework. Above all, Cardinal will help you solve the paramount challenge of software development: not only to solve the problem right, but also to solve the right problem. You will learn how to •    Establish more effective agile roles for analysts and architects •    Integrate and simplify the best techniques from FIT, ATDD, and BDD •    Identify “core certainties” on which your project team should rely to ensure requirements discovery •    Manage uncertainty by discovering stakeholder desires through short feedback loops •    Specify as you go while writing small chunks of requirements •    Use storyboarding and paper prototyping to improve conversations with stakeholders •    Express stakeholder desires that are requirements with user stories •    Refine your user stories, and plan more effective Scrum sprints •    Confirm user stories by scripting behaviors with scenarios •    Transform scenarios into automated tests that easily confirm your software’s expected behavior as designs emerge and specifications evolve •    Ensure higher-quality software by specifying nonfunctional requirements

Table of Contents:
Preface     xvi Chapter 1  Solving the Right Problem     1 Distinguishing the Requirements from the Solution     4 Recognizing the Impact of Uncertainty     5 Tackling Uncertainty    7 Summary     10 References     10 Chapter 2  Relying on a Stable Foundation     13 Defining What Will Hardly Change     14 Creating a Healthy Team     14 Requiring the Involvement of All Stakeholders     16 Expressing a Shared Vision     17 Distinguishing a Meaningful Common Goal     20 Identifying a Set of High-Level Features     21 Validating the “Can-Exist” Assumption     22 Summary     23 References     23 Chapter 3  Discovering Through Short Feedback Loops and Stakeholders’ Desirements     25 Applying the Trial-and-Error Method     25 Using Short Feedback Loops     29 Targeting Feedback Along the Expected Benefits     31 Focusing on the Stakeholders’ Desirements     31 Summary     34 References     34 Chapter 4  Expressing Desirements with User Stories     35 Describing Desirements by Using User Stories     35 Discovering Desirements by Exploring Roles and Benefits     38 Establishing a Ubiquitous Language     40 Recording Desirements by Using a Product Backlog     41 Summary     43 References     44 Chapter 5  Refining User Stories by Grooming the Product Backlog     45 Managing the Product Backlog     46 Collaborating to Groom the Product Backlog     48 Ranking User Stories with a Dot Voting Method     49 Illustrating User Stories with Storyboards     52 Sizing User Stories Using Comparison     56 Splitting User Stories Along Business Values     60 Tracking User Stories with a Collaboration Board     62 Delivering a Coherent Set of User Stories     68 Planning Work with User Stories     70 Summary     71 References     72 Chapter 6  Confirming User Stories with Scenarios     73 Scripting User Stories with Scenarios     74    Expressing Scenarios with Formality     76    Scripting Scenarios Using the FIT Tabular Format     77    Scripting Scenarios Using Given-When-Then Syntax     79    Choosing Between FIT Tabular Format or Given-When-Then Syntax     80    Formalizing a Ubiquitous Language     81    Splitting Scenarios into Commands or Queries     83 Confirming Collaboratively in a Two-Step Process     85 Removing Technical Considerations from Scenarios     89 Evolving Scenarios from Sprint to Sprint     91    Organizing Scenarios by Feature     92    Documenting Scenarios by Feature     93    Avoiding Duplication and Merging Conflicts     94 Summary     95 References     96 Chapter 7  Automating Confirmation with Acceptance Tests     97 Evolving Scenarios into Acceptance Tests     98 Automating Scenarios Using the Red-Green-Refactor Cycle     101 Translating the Scenario into an Acceptance Test     104    Transposing Using an Internal DSL     104    Creating a Test     107    Coding the DSL into the Newly Created Test     108 Connecting the Newly Created Test with the Interface     110    Exercising the Interface     112    Chaining Context Between the Steps of the Scenario     113    Making the Test Fail     114 Implementing the Interface     115    Replacing Unit Testing with Context-Specification Testing     116    Making the Test Pass     117 Evolving the Acceptance Test     117 Running Acceptance Tests Side-by-Side with Continuous Integration     118 Enhancing Scenarios with Test Results     119 Summary     121 References     122 Chapter 8  Addressing Nonfunctional Requirements     123 Improving External Quality Using Restrictions     125 Translating Nonfunctional Requirements into Restrictions     127 Reducing the Functional Scope to a Single Scenario     129 Setting Measurable Quality Objectives     131 Testing Restrictions with Proven Practices     135 Ensuring Internal Quality Using Sound Engineering Practices     137    Improving Software Construction with Explicit Practices     137    Mastering Practices with Collaborative Construction     140 Summary     142 References     143 Chapter 9  Conclusion     145 Recapitulating the Book     146 Summarizing the Process     148 Drawing Attention to Individual Roles     149 Glossary     153 Index     159