A test system and method of testing are provided. In some embodiments, a system for testing an integrated circuit package includes a device tester. The device tester includes a socket, a cylinder head unit engageable with the socket, and a pressure regulator. The socket includes a first pressure cylinder configured to engage a first region of the integrated circuit package and a second pressure cylinder configured to engage a second region of the integrated circuit package. The pressure regulator is configured to provide at gas at a first pressure to the first pressure cylinder and to provide the gas at a second pressure different than the first pressure to the second pressure cylinder.