1 

     2 assert(run("[-]", Map(0 -> 100)) == Map(0 -> 0))

     3 assert(run("[->+<]", Map(0 -> 10)) == Map(0 -> 0, 1 -> 10))

     4 assert(run("[>>+>>+<<<<-]", Map(0 -> 42)) == Map(0 -> 0, 2 -> 42, 4 -> 42))

     5 val hw_urban = """+++++[->++++++++++<]>--<+++[->>++++++++++

     6                   <<]>>++<<----------[+>.>.<+<]"""

     7 assert(run(hw_urban) == Map(0 -> 0, 1 -> 58, 2 -> 32))

     8