Abstract: A multi-functional completion tool which may be lowered into a wellbore coupled to a length of tubing, and then utilized to test various lengths of the tubing at pressure. The tool may also function as a positive plug and may also be used to set the packer, and is also useable as a tubing self-filling tool. Various retention elements are disposed within the tool and configured to release at predetermined pressures, or within predetermined ranges of pressure, thereby transforming the tool from a first configuration to a second configuration depending on the desired function. The tool may also contain a pressure-regulating assembly for regulating the differential pressure across the assembly. The tool may also include an indicator assembly for confirming that the tool has entered a plugging configuration, typically by altering a pressure within the tubing, such alteration being detectible at a surface location.