On the Characterization of $1$-sided error Strongly-Testable Graph Properties for bounded-degree graphs, including an appendix

We study property testing of (di)graph properties in bounded-degree graph models. The study of graph properties in bounded-degree models is one of the focal directions of research in property testing in the last 15 years. However, despite of the many results and the extensive research effort, there is no characterization of the properties that are strongly-testable (i.e., testable with constant query complexity) even for $1$-sided error tests. The bounded-degree model can naturally be generalized to directed graphs resulting in two models that were considered in the literature. The first contains the directed graphs in which the outdegree is bounded but the indegree is not restricted. In the other, both the outdegree and indegree are bounded. We give a characterization of the $1$-sided error strongly-testable {\em monotone} graph properties, and the $1$-sided error strongly-testable {\em hereditary} graph properties in all the bounded-degree directed and undirected graphs models.