require 'optparse'

parser = OptionParser.new
parser.on("-a <N>", "int #1", Integer)
parser.on("-b <N>", "int #2", Integer, [1,2,3])     # with enum (integer)
parser.on("-c <N>", "int #3", Integer, ["1", "2"])  # with enum (string)

## Without enum, parser parses args successfully.
opts = {}
parser.parse(["-a", "2"], into: opts)   # ok
p opts     #=> {:a=>2}

## [BUG] With enum (integer), parser raises InvalidArgument error.
opts = {}
#parser.parse(["-b", "2"], into: opts)  #=> OptionParser::InvalidArgument

## [BUG] With enum (string), parser doesn't convert value into an integer.
opts = {}
parser.parse(["-c", "2"], into: opts)   # no exception
p opts     #=> {:c=>"2"}  (expected: {:c=>2})