Testing styled text (12<b>3<i>456</i></b>)
(0, 0): 
(0, 2): 12
(0, 3): 123
(0, 6): 123456
(0, 7): 123456
(0, 100): 123456
(5, 1): 6
(5, 2): 6
(100, 0): undefined
(100, 100): undefined

Testing proper space runs (1._2.__3.___4_5)
total length: 15
one space: " "
two spaces: "  "
three spaces: "   "
four spaces: "    "

Testing space-only runs (1..2...3....4.5)
total length: 9
(0, 100): 1 2 3 4 5