Abstract: A pipe testing tool in the form of an elongated tubular member positionable within a pipe and which includes spaced, radially expandable sealing rings to contact the inner surface of the pipe and define at test section. The tool includes a through bore to carry pressurizing fluid which is used to cause the sealing rings to expand and then to pressurize the test section for leakage testing. A radial conduit from the through bore provides communication with a movable cylinder to compress the sealing rings and an escape chamber is provided to permit pressure release of trapped air between the cylinder and the sealing rings. The radial conduit is preferably spaced at least two conduit diameters away from a threaded portion to reduce stress concentrations and thereby avoid failure of the tool due to flexing during handling and use thereof.