Building software systems that adapt to changing resource environments is challenging: developers cannot anticipate all future situations that a software system may face, and even if they could, the effort required to handle such situations would often be too onerous for practical purposes. We propose a novel approach to allow a system to generate resource usage adaptations: use delta-debugging to generate versions of software systems that are reduced in size because they no longer have to satisfy all tests in the software’s test suite. Many such variations will, while retaining core system functionality, use fewer resources. We describe an tool for computing such adaptations, based on our notion that labeled subsets of a test suite can be used to conveniently describe possible relaxations of system specifications. Using the NetBeans IDE, we demonstrate that even without additional infrastructure or heuristics, our approach is capable of quickly and cleanly removing a program’s undo functionality, significantly reducing its memory use, with no more effort than simply labeling three test cases as undo-related.