Added tests for b_prefixes()
Added tests for b_prefixes()

moonlet/DAWG,moonlet/DAWG,moonlet/DAWG,pombredanne/DAWG,moonlet/DAWG,kmike/DAWG,pombredanne/DAWG,pytries/DAWG,kmike/DAWG,kmike/DAWG,pombredanne/DAWG,pytries/DAWG,pytries/DAWG,pytries/DAWG,kmike/DAWG,kmike/DAWG,pombredanne/DAWG