require "test/unit"

class Bitset

attr_reader :no

def initialize no

@no = no

end

def toggle nth

@no ^= 1 << nth

end

def turn_on nth

@no |= 1 << nth

end

def turn_off nth

@no &= ~(1 << nth)

end

def union set

Bitset.new(@no | set.no)

end

def to_s

"0b#{@no.to_s(2)}"

end

end

class TestBitSet < Test::Unit::TestCase

def setup

@bs = Bitset.new(16) # 0b10000

end

def test_turn_on

@bs.turn_on(nth=0); assert_equal("0b10001", @bs.to_s)

@bs.turn_on(nth=1); assert_equal("0b10011", @bs.to_s)

end

def test_turn_off

@bs.turn_off(nth=0); assert_equal("0b10000", @bs.to_s)

@bs.turn_on (nth=2); assert_equal("0b10100", @bs.to_s)

@bs.turn_off(nth=2); assert_equal("0b10000", @bs.to_s)

end

def test_toggle

@bs.toggle(nth=0); assert_equal("0b10001", @bs.to_s)

@bs.toggle(nth=0); assert_equal("0b10000", @bs.to_s)

@bs.toggle(nth=1); assert_equal("0b10010", @bs.to_s)

@bs.toggle(nth=1); assert_equal("0b10000", @bs.to_s)

end

def test_union

bs1 = Bitset.new(2)

bs2 = @bs.union(bs1)

assert_equal("0b10010", bs2.to_s)

end

end