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ACMD Seminar: Embedded functions in combinatorial testing: Progress in automating test design

George Sherwood
Founder and CEO of

Wednesday, October 11, 2017, 15:00 - 16:00
Building 101, Lecture Room D

Wednesday, October 11, 2017, 13:00 - 14:00
Room 1-4058

Slides: PowerPoint Adobe PDF

Host: Raghu Kacker

Abstract: This talk introduces combinatorial testing (CT), from its origins in design of experiments to its present role in verifying interactions in complex systems. A persistent CT usability challenge has been the definition and enforcement of constraints among test factor values. Research progress in this area has enabled increased adoption among practicing software engineers. Recent work at led to the introduction of an embedded functions feature in its CT design service. The feature allows functionally dependent relations among test factors to be defined as functions in a general purpose programming language, PHP. These relations enforce constraints among test factor values and insure that all valid combinations of determinant factors are available for the test design. Resulting usability improvements enable automated pairwise test designs to meet novel objectives: Cover equivalence classes of expected results; verify univariate and multivariate equivalence class boundaries; verify corners among intersecting boundaries and edges.

Bio: George Sherwood is the founder and CEO of, which provides Software as a Service for combinatorial test designs. He has been actively involved in combinatorial testing since 1990. Then, during the development of a LAN product at AT&T Bell Labs, his test team encountered multi-vendor configurations too numerous to test. His response was to develop CATS, a test design tool using a greedy search to accommodate system constraints. Subsequently CATS was used in several other AT&T development programs. At the Labs George worked on hardware, software and service development projects, and he managed teams of engineers in a variety of disciplines.

In 2003 George founded to enable software engineers to design test plans with more effective test cases. He has found innovative constructions for covering arrays, and he has devised advanced search algorithms for Recent work includes development of embedded functions technology, to simplify constraint specification for practicing software engineers.

George has degrees in physics, a Ph.D. from Yale University and a B.S. from Clemson University. He serves on the board of the Princeton Joint Professional Chapter of the ACM and IEEE Computer Society.


Created September 25, 2017, Updated November 15, 2019