A method of testing pipes for use in making subsea pipelines comprises cutting a ring from one or more pipes of the type used to make the pipeline; forming flat, substantially parallel surfaces on the ends of the ring; providing means for measuring strain and deformation of the ring; mounting the ring in a pressure chamber such that the ends of the ring form seals with opposing walls of the chamber to isolate the inside of the ring from the outside; increasing the pressure outside the ring and measuring the strain and deformation on the ring as the pressure increases; and using the deformation and strain measurements to determine a wall thickness for pipes to be used for the pipeline. An apparatus for testing rings cut from pipes for use in making subsea pipelines, comprises first and second test chamber sections which, when placed together define a test chamber for receiving the ring to be tested; one or more sensors for measuring strain and deformation of the ring; sealing means located in the chamber for forming a seal against the ring when received in the chamber; means for clamping the first and second sections together to form the chamber and engage the sealing means against the ring when received in the chamber to form a pressure resistant seal between the inside and outside of the ring; and a fluid inlet port in one of the chamber sections to allow a pressurised fluid to be admitted to the chamber outside the ring when received in the chamber.