An exemplary testing device includes a shell, a motor, a wheel rotating eccentrically, a testing plug, and a sliding assembly. The sliding assembly is configured to move back and forth along a first direction in a first accommodating space of the shell. A periphery of the wheel abuts against two opposite sides of the sliding assembly. An eccentricity e defined between a eccentric hole of the wheel and the center of the wheel causes the sliding assembly to move back and forth along the first direction when the wheel rotates eccentrically. The testing plug connects to the sliding assembly and moves back and forth in unison with the sliding assembly, such that the testing plug can be inserted into the interface of the electronic device more than once.