Abstract: An apparatus for the hydrostatic testing of pipe and pipe connections is provided. The apparatus features an elongated tool body which can be inserted into the interior portion of a connected series of pipe joints or the like. The device is inserted into a pipe joint in proximity to a connection between two joints which has been "made up" by means of, for example, a threaded connection. The device utilizes a pair of expanding flexible packing seals which expand and sealably contact the pipe wall forming a pressure test area between the seals and at the pipe joint to be tested. Fluid pressure supplied through a central conduit in the tool body flows into the pipe between the packing seals through a nozzle injector in the tool body in proximity to the joint which is to be tested. The test fluid then first expands the pair of flexible seals and fills the pipe with water upon which a desired test pressure is exerted.