  With the increasing popularity of continuous integration, algorithms for
selecting the minimal test-suite to cover a given set of changes are in order.
This paper reports on how polymorphism can handle false negatives in a previous
algorithm which uses method-level changes in the base-code to deduce which
tests need to be rerun. We compare the approach with and without polymorphism
on two distinct cases ---PMD and CruiseControl--- and discovered an interesting
trade-off: incorporating polymorphism results in more relevant tests to be
included in the test suite (hence improves accuracy), however comes at the cost
of a larger test suite (hence increases the time to run the minimal
test-suite).
