This test checks the "stroke-dasharray" and "stroke-dashoffset" properties. Two lines are drawn, one blue and one black. Both have a "stroke-dasharray" of "10,10" giving a dashed appearance where the size of the gaps and the size of the dash is equal.
The black line is lower than but parallel to the blue line. The "stroke-dashoffset" on each line should make the dashes of each line line up with the gaps in the other line.