public interface Predicate<T>
Many apps use Guava. If a test apk also contains a copy of Guava, duplicated classes in app and test apks may cause error at run-time: "Class ref in pre-verified class resolved to unexpected implementation". To simplify the build and deployment set-up, DroidDriver copies the code of some Guava classes (often simplified) to this package such that it does not depend on Guava.
boolean apply(T input)
It is recommended that this method return the description of this Predicate.