Copyright Preface Organization Audience Acknowledgments Chapter 1. Requirements Phase Item 1: Involve Testers from the Beginning Item 2: Verify the Requirements Item 3: Design Test Procedures As Soon As Requirements Are Available Item 4: Ensure That Requirement Changes Are Communicated Item 5: Beware of Developing and Testing Based on an Existing System Chapter 2. Test Planning Item 6: Understand the Task At Hand and the Related Testing Goal Item 7: Consider the Risks Item 8: Base Testing Efforts on a Prioritized Feature Schedule Item 9: Keep Software Issues in Mind Item 10: Acquire Effective Test Data Item 11: Plan the Test Environment Item 12: Estimate Test Preparation and Execution Time Chapter 3. The Testing Team Item 13: Define Roles and Responsibilities Item 14: Require a Mixture of Testing Skills, Subject-Matter Expertise, and Experience Item 15: Evaluate the Tester's Effectiveness Chapter 4.
The System Architecture Item 16: Understand the Architecture and Underlying Components Item 17: Verify That the System Supports Testability Item 18: Use Logging to Increase System Testability Item 19: Verify That the System Supports Debug and Release Execution Modes Chapter 5. Test Design and Documentation Item 20: Divide and Conquer Item 21: Mandate the Use of a Test- Procedure Template and Other Test- Design Standards Item 22: Derive Effective Test Cases from Requirements Item 23: Treat Test Procedures As "Living" Documents Item 24: Utilize System Design and Prototypes Item 25: Use Proven Testing Techniques when Designing Test-Case Scenarios Item 26: Avoid Including Constraints and Detailed Data Elements within Test Procedures Item 27: Apply Exploratory Testing Chapter 6. Unit Testing Item 28: Structure the Development Approach to Support Effective Unit Testing Item 29: Develop Unit Tests in Parallel or Before the Implementation Item 30: Make Unit-Test Execution Part of the Build Process Chapter 7. Automated Testing Tools Item 31: Know the Different Types of Testing-Support Tools Item 32: Consider Building a Tool Instead of Buying One Item 33: Know the Impact of Automated Tools on the Testing Effort Item 34: Focus on the Needs of Your Organization Item 35: Test the Tools on an Application Prototype Chapter 8.
Automated Testing: Selected Best Practices Item 36: Do Not Rely Solely on Capture/Playback Item 37: Develop a Test Harness When Necessary Item 38: Use Proven Test-Script Development Techniques Item 39: Automate Regression Tests When Feasible Item 40: Implement Automated Builds and Smoke Tests Chapter 9. Nonfunctional Testing Item 41: Do Not Make Nonfunctional Testing an Afterthought Item 42: Conduct Performance Testing with Production-Sized Databases Item 43: Tailor Usability Tests to the Intended Audience Item 44: Consider All Aspects of Security, for Specific Requirements and System- Wide Item 45: Investigate the System's Implementation To Plan for Concurrency Tests Item 46: Set Up an Efficient Environment for Compatibility Testing Chapter 10. Managing Test Execution Item 47: Clearly Define the Beginning and End of the Test-Execution Cycle Item 48: Isolate the Test Environment from the Development Environment Item 49: Implement a Defect-Tracking Life Cycle Item 50: Track the Execution of the Testing Program Copyright Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and Addison-Wesley was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals.
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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior consent of the publisher. Printed in the United States of America. Published simultaneously in Canada.
For information on obtaining permission for use of material from this work, please submit a written request to: Pearson Education, Inc. Rights and Contracts Department 75 Arlington Street, Suite 300 Boston, MA 02116 Fax: (617) 848-7047 Text printed on recycled paper 1 2 3 4 5 6 7 8 9 10— MA— 0605040302 First printing, December 2002 Dedication To Jackie, Erika, and Cedric Preface In most software-development organizations, the testing program functions as the final "quality gate" for an application, allowing or preventing the move from the comfort of the software-engineering environment into the real world. With this role comes a large responsibility: The success of an application, and possibly of the organization, can rest on the quality of the software product. A multitude of small tasks must be performed and managed by the testing team— so many, in fact, that it is tempting to focus purely on the mechanics of testing a software application and pay little attention to the surrounding tasks required of a testing program.
Issues such as the acquisition of proper test data, testability of the application's requirements and architecture, appropriate test-procedure standards and documentation, and hardware and facilities are often addressed very late, if at all, in a project's life cycle. For projects of any significant size, test scripts and tools alone will not suffice— a fact to which most experienced software testers will attest. Knowledge of what constitutes a successful end-to-end testing effort is typically gained through experience. The realization that a testing program could have been much more effective had certain tasks been performed earlier in the project life cycle is a valuable lesson.
Of course, at that point, it's usually too late for the current project to benefit from the experience. Effective Software Testing provides experience-based practices and key concepts that can be used by an organization to implement a successful and efficient testing program. The goal is to provide a distilled collection of techniques and discussions that can be directly applied by software personnel to improve their products and avoid costly mistakes and oversights. This book details 50 specific software testing best practices, contained in ten parts that roughly follow the software life cycle.
This structure itself illustrates a key concept in software testing: To be most effective, the testing effort must be integrated into the software-development process as a whole. Isolating the testing effort into one box in the "work flow" (at the end of the software life cycle) is a common mistake that must be avoided. The material in the book ranges from process- and management-related topics, such as managing changing requirements and the makeup of the testing team, to technical aspects such as ways to improve the testability of the system and the integration of unit testing into the development process. Although some pseudocode is given where necessary, the content is not tied to any particular technology or application platform.
It is important to note that there are factors outside the scope of the testing program that bear heavily on the success or failure of a project. Although a complete software-development process with its attendant testing program will ensure a successful engineering effort, any project must also deal with issues relating to the business case, budgets, schedules, and the culture of the organization. In some cases, these issues will be at odds with the needs of an effective engineering environment. The recommendations in this book assume that the organization is capable of adapting, and providing the support to the testing program necessary for its success.
Organization This book is organized into 50 separate items covering ten important areas. The selected best practices are organized in a sequence that parallels the phases of the system development life cycle. The reader can approach the material sequentially, item-by-item and part-by-part, or simply refer to specific items when necessary to gain information about and understanding of a particular problem. For the most part, each chapter stands on its own, although there are references to other chapters, and other books, where helpful to provide the reader with additional information.
Chapter 1 describes requirements-phase considerations for the testing effort. It is important in the requirements phase for all stakeholders, including a representative of the testing team, to be involved in and informed of all requirements and changes. In addition, basing test cases on requirements is an essential concept for any large project. The importance of having the testing team represented during this phase cannot be overstated; it is in this phase that a thorough understanding of the system and its requirements can be obtained.
Chapter 2 covers test-planning activities, including ways to gain understanding of the goals of the testing effort, approaches to determining the test strategy, and considerations related to data, environments, and the software itself. Planning must take place as early as possible in the software life cycle, as lead times must be considered for implementing the test program successfully. Early planning allows for testing schedules and budgets to be estimated, approved, and incorporated into the overall software development plan. Estimates must be continually monitored and compared to actuals, so they can be revised and expectations can be managed as required.
Chapter 3 focuses on the makeup of the testing team. At the core of any successful testing program are its people. A successful testing team has a mixture of technical and domain knowledge, as well as a structured and concise division of roles and responsibilities. Continually evaluating the effectiveness of each test- team member throughout the testing process is important to ensuring success.
Chapter 4 discusses architectural considerations for the system under test. Often overlooked, these factors must be taken into account to ensure that the system itself is testable, and to enable gray-box testing and effective defect diagnosis. Chapter 5 details the effective design and development of test procedures, including considerations for the creation and documentation of tests, and discusses the most effective testing techniques. As requirements and system design are refined over time and through system-development iterations, so must the test procedures be refined to incorporate the new or modified requirements and system functions.
Chapter 6 examines the role of developer unit testing in the overall testing strategy. Unit testing in the implementation phase can result in significant gains in software quality. If unit testing is done properly, later testing phases will be more successful. There is a difference, however, between casual, ad-hoc unit testing based on knowledge of the problem, and structured, repeatable unit testing based on the requirements of the system.
Chapter 7 explains automated testing tool issues, including the proper types of tools to use on a project, the build-versus-buy decision, and factors to consider in selecting the right tool for the organization. The numerous types of testing tools available for use throughout the phases in the development life cycle are described here. In addition, custom tool development is also covered. Chapter 8 discusses selected best practices for automated testing.
The proper use of capture/playback tools, test harnesses, and regression testing are described. Chapter 9 provides information on testing nonfunctional aspects of a software application. Ensuring that nonfunctional requirements are met, including performance, security, usability, compatibility, and concurrency testing, adds to the overall quality of the application. Chapter 10 provides a strategy for managing the execution of tests, including appropriate methods of tracking test-procedure execution and the defect life cycle, and gathering metrics to assess the testing process.
Audience The target audience of this book includes Quality Assurance professionals, software testers, and test leads and managers.