shaping: padding 0

Skip if the two sequences to the right have different shapes: ععع ععع.
Test passes if the three Arabic characters join, making the two boxes identical.

Assertion: Shaping is not broken across inline box boundaries when padding is set to 0.

The middle character of the top box is surrounded by a span element to which the CSS "padding:0" is applied. The lower box uses ZWJ between characters and markup to show the expected outcome.
The 'skip' directive compares a sequence separated by unstyled span markup to one without. If the displayed results are different this test will always fail, regardless of the styling, and should be skipped.
The test uses a Noto Naskh Arabic webfont to control variables related to font choice.