1 Test that an element supports z-index once it is a grid item and it is repainted properly.
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
6 Test z-index property for a regular element
7 PASS getComputedStyle(item, '').getPropertyValue('z-index') is 'auto'
8 PASS getComputedStyle(item, '').getPropertyValue('z-index') is 'auto'
9 Test z-index property once the element becomes a grid item
10 PASS getComputedStyle(item, '').getPropertyValue('z-index') is '-10'
11 PASS getComputedStyle(item, '').getPropertyValue('z-index') is '10'
12 PASS successfullyParsed is true