Better Software - March 2008 - (Page 40)

n critical projects, testers are commonly required to design, maintain, and execute a regression test suite to certify an application before it is deployed in production. In this case, we are concerned with the test suite completeness, as our final application certification is only as good as the regression suite coverage. To be used as a frame of reference, a conventional test-coverage measurement technique requires complete software requirements. We then establish traceability between requirements and related tests that allows us to measure test coverage and identify coverage gaps. However, testers in the field commonly deal with incomplete and even missing software requirements. On such projects, they do not have sufficient visibility into the application’s test coverage. This article provides a solution that I have found to be effective for this problem on many critical projects. The solution, a technique called requirements composition table (RCT), allows testers to assess the regression test suite completeness and identify test coverage gaps. Once gaps are identified, testers can better decide how to evolve the regression test suite to improve the application’s test coverage. The RCT is based on the insight that we do not need descriptions of software requirements in order to measure regression test coverage and identify coverage gaps; just having their inventory and structure can be sufficient. Identifying coverage gaps using this technique involves six steps: 1. Decompose the application functionality. 2. Identify core features. 3. Identify crosscutting concerns. 4. Develop a requirements composition table. 5. Establish traceability between requirements and regression tests. 6. Measure test coverage and identify gaps. I illustrate the technique using an imaginary hotel management system (HMS). The following are terms used in its workflow: 40 BETTER SOFTWARE MARCH 2008 O Figure 1: Application functional decomposition • Core feature—This is a unit of the application functionality that, being executed, allows the user to achieve a particular business goal (result). For example, functionality captured by use cases can be qualified as core features. • Crosscutting concern—This term comes from the aspect-oriented software development methodology (see the StickyNotes for more information). It refers to a specific category of software requirements that are scattered across the application and tangled with core features. ing rate plans, etc. • 03. Accounting—used by accounting personnel for creating and reviewing financial statements, conducting cashier audits, maintaining credit card limits, etc. • 04. Housekeeping—used by housekeeping staff for maintaining the cleaning and occupancy statuses of rooms, assigning rooms to attendants, etc. • 05. System Setup—used by hotel management for setting up hotel property defaults and user profiles, managing tax codes and charge codes, etc. Each module still presents a complex chunk of functionality, so we continue decomposition from the second perspective—types of requirements—where we want to separate software requirements by different categories (i.e., concerns). Business applications implement core features that allow the user to achieve concrete business goals. They can be presented from the end-user perspective and specified by use cases. In addition, business applications are implemented based on some generic engineering principles related to data-entry validations, user role validations, concurrency control, handling front-end connectivity, data exchange with other systems, etc. We begin our anaysis by decomposing the application functionality into a high-level structure of functional requirements from two perspectives: application modules and types of functional requirements. Our HMS application can have the following modules: • 01. Front Desk—used by frontdesk clerks for creating and managing reservations, handling financial charges, etc. • 02. Hotel Management—used by hotel management for managwww.StickyMinds.com http://www.StickyMinds.com

Table of Contents Feed for the Digital Edition of Better Software - March 2008

Better Software - March 2008 Contents Mark Your Calendar Contributors eLightenment Technically Speaking Code Craft Test Connection Management Chronicles Cover Story: Breaking Ground On SOA Software Development Worst Practices Mind the Gap Product Announcements 10 Things You Might Not Know About... The Last Word Ad Index

Better Software - March 2008

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