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