The font for this test case is an AAT version of the Billion laughs attack. It contains an AAT Extended Glyph Metamorphosis Table with nine identical Glyph Insertion Subtables whose embedded finite-state machine inserts the string hahahahahahahahahaha for every a in the input string. If the input is “ha” (one single laugh), the first subtable rewrites it to 10 laughs. The second subtable rewrites 10 to 100 laughs; the third goes from 100 to 1000; the fourth from 1000 to 10,000. After executing the ninth subtable, the final result will be a billion laughs, but this will take a very long time (and large amounts of memory) to compute. Your implementation should neither crash nor hang under attack. See also fontkit bug 174.