'Rect' elements with unspecified 'rx' and 'ry' attributes will use the specified 'rx' and 'ry' value if the other one is specified; if neither is specified, the 'rect' has square edges.
Creates one 'rect' element with an unspecified 'ry'. Places it over a red 'rect' element with both 'rx' and 'ry' specified. Repeat with unspecified 'rx'. Finally creates a 'rect' element that has neither 'rx' or 'ry' specified.
Run the test. No interaction required.
Test passes if the two shapes on top are rounded rectangles, the shape below has square corners, and no red is visible on the page.