Apparatuses, systems and methods associated with integrated circuit packages with integrated test circuitry for testing of a channel between dies are disclosed herein. In embodiments, an integrated circuit (IC) package may include a first die, a second die, and a channel that couples the first die to the second die. The first die may include a transmitter, test circuitry coupled between the transmitter and the channel, wherein the test circuitry is to control charge and discharge of the channel, and a receiver coupled to the channel. The receiver may determine a voltage of the channel during charge and discharge of the channel, and output an indication of the voltage. Other embodiments may be described and/or claimed.