Nest Labs Unit Test (nlunit-test) is a simple, portable unit test suite framework, capable of running on just about any system, no matter how constrained and depends only on the C Standard Library.
When nlunit-test is a subpackage as part of a larger package that uses recursive configuration with a cache (for example, configure -C), then settings made on behalf of NL_ENABLE_COVERAGE or NL_ENABLE_COVERAGE_REPORTS cause missing or conflicting entries in the cache file and then cause "flapping" of those values in subsequent cache files and their resultant configurations.