Display device and testing method of sensing unit thereof

A display device includes first and second display signal lines, pixels, first and second sensing signal lines, first through fourth test lines for transmitting first through fourth test signals, a first switching element connected to the first and second test lines, and the first sensing signal line, second switching elements connected to the first switching element, the second test line, and a subset of first display signal lines, a third switching element connected to the third and fourth test lines, and the second sensing signal line, and fourth switching elements connected to the third switching element, the fourth test line, and a subset of second display signal lines.