A mobile apparatus for testing the integrity of a joint between two sections of concrete pipe in a test-as-you-go method of assembling concrete pipe sections to form a continuous pipe. The apparatus includes a wheel mounted frame which carries a flexible seal used to cover the interior of the entire pipe joint to form a substantially closed annular space. That space and a connected tank provide a substantially known volume for measurement purposes. The pressure in the known volume is monitored over a set period of time to determine the integrity of the pipe joint. The apparatus is moved along the interior of the pipe to test each joint after it is assembled. A method of testing the pipe joints is also disclosed.
