Multicast Listener Discovery (MLD) is one of the sub-protocols of the IPv6 family. It is used by IPv6 routers to discover the presence of multicast listeners and specifically, which multicast addresses are of interest to the neighboring nodes of the MLD capable routers. This information is then provided to whichever multicast routing protocol (like PIM) is being used by the router for other (e.g. WAN) communication. The goal of this document is to provide a concise methodology on testing MLD capable devices from a security perspective. Although a lot of different testing cases are described both for MLDv1 and MLDv2, by no means can the list of the presented scenarios be considered as an exhaustive one. However, it can serve as a really good basis for testing your MLD devices and, if required, expanding the tests.