A method of testing a suspend operation, the method including: determining whether to transfer a suspend sampling signal to a suspend command circuit at a time point prior to each of a plurality of suspend operation time points stored in a sequence operation circuit; transferring the suspend sampling signal from the sequence operation circuit to the suspend command circuit; generating an internal suspend operation command based on the suspend sampling signal; transferring the internal suspend operation command from the suspend command circuit to the sequence operation circuit; performing suspend operations for all the plurality of suspend operation time points in response to the internal suspend operation command; and determining whether the suspend operations are performed at all of the suspend operation time points.