Here is my solution for this quiz. Nothing too fancy really, but it does the job. I suspect if I used this more for various applications I'd find more clever things to do. But I did replace some command-line input/output in another program of mine with this library, and it definitely cleaned things up. It certainly makes sense to put this kind of stuff in a library instead of always rolling your own.
I never did look at the EasyPrompt code, but I suspect this code might look very similar because of my use of a MockIO object (I did notice that much from the EasyPrompt summary.) But I suppose it is good that the unit tests and MockIO object are more lines of code than the library 
I would appreciate feedback on the API design as well as the unit test design. I feel the unit tests are too coupled to the implementation (particularly on my checking of the output.)
Ryan Leavengood
CODE (beware of wrapping):
···
#--------------------------------------
# HighLine command-line input library
#
# Copyright (C) 2005 Ryan Leavengood
#
# Released under the Ruby license
#--------------------------------------
class String
def pad_if_needed
self[-1].chr != ' ' ? self + ' ' : self
end
end
class HighLine
attr_accessor :io_out, :io_in
def initialize(io_out=$stdout, io_in=$stdin)
@io_out, @io_in = io_out, io_in
end
def ask(question, default=nil)
q = question.pad_if_needed
q += "[#{default}] " if default
answer = validation_loop(q) do |input|
input.size > 0 or default
end
answer.size > 0 ? answer : default
end
def ask_if?(question)
answer = validation_loop(question.pad_if_needed+'(y,n) ') do |input|
%w(y n yes no).include?(input.downcase)
end
answer.downcase[0,1] == 'y'
end
def ask_int(question, range=nil)
validation_loop(question) do |input|
input =~ /\A\s*-?\d+\s*\Z/ and (not range or range.member?(input.to_i))
end.to_i
end
def ask_float(question, range=nil)
validation_loop(question) do |input|
input =~ /\A\s*-?\d+(.\d*)?\s*\Z/ and (not range or range.member?(input.to_f))
end.to_f
end
def header(title)
dashes = '-'*(title.length+4)
io_out.puts(dashes)
io_out.puts("| #{title} |")
io_out.puts(dashes)
end
def list(items, prompt=nil)
items.each_with_index do |item, i|
@io_out.puts "#{i+1}. #{item}"
end
valid_range = '1'..items.length.to_s
prompt = "Please make a selection: " unless prompt
answer = validation_loop(prompt) do |input|
valid_range.member?(input)
end
# Though the list is shown using a 1-indexed list, return 0-indexed
return answer.to_i-1
end
def validation_loop(prompt)
loop do
@io_out.print prompt.pad_if_needed
answer = @io_in.gets
if answer
answer.chomp!
if yield answer
return answer
end
end
end
end
end
# Unit Tests
if $0 == __FILE__
class MockIO
attr_accessor :output, :input
def initialize
reset
end
def reset
@index = 0
@input=nil
@output=''
end
def print(*a)
@output << a.join('')
end
def puts(*a)
if a.size > 1
@output << a.join("\n")
else
@output << a[0] << "\n"
end
end
def gets
if @input.kind_of?(Array)
@index += 1
@input[@index-1]
else
@input
end
end
end
require 'test/unit'
class TC_HighLine < Test::Unit::TestCase
def initialize(name)
super(name)
@mock_io = MockIO.new
@highline = HighLine.new(@mock_io, @mock_io)
end
def setup
@mock_io.reset
end
def test_ask
question = 'Am I the coolest?'
@mock_io.input = [nil, '', "\n", "yes\n"]
assert_equal(@mock_io.input[-1].chomp, @highline.ask(question))
assert_equal((question+' ')*4, @mock_io.output)
end
def test_ask_default
question = 'Where are you from? '
default = 'Florida'
@mock_io.input = [nil, "\n"]
assert_equal(default, @highline.ask(question, default))
assert_equal((question+"[#{default}] ")*2, @mock_io.output)
end
def test_ask_if
question = 'Is Ruby the best programming language? '
@mock_io.input = [nil, "0\n", "blah\n", "YES\n"]
assert_equal(true, @highline.ask_if?(question))
assert_equal((question+'(y,n) ')*4, @mock_io.output)
end
def test_ask_int
question = 'Give me a number:'
@mock_io.input = [nil, '', "\n", ' ', "blah\n", " -4 \n"]
assert_equal(-4, @highline.ask_int(question))
assert_equal((question+' ')*6, @mock_io.output)
@mock_io.reset
@mock_io.input = [nil, '', "\n", ' ', "blah\n", "3604\n"]
assert_equal(3604, @highline.ask_int(question))
assert_equal((question+' ')*6, @mock_io.output)
end
def test_ask_int_range
question = 'How old are you?'
@mock_io.input = [nil, '', "\n", ' ', "blah\n", "106\n", "28\n"]
assert_equal(28, @highline.ask_int(question, 0..105))
assert_equal((question+' ')*7, @mock_io.output)
end
def test_ask_float
question = 'Give me a floating point number:'
@mock_io.input = [nil, '', "\n", ' ', "blah\n", " -4.3 \n"]
assert_equal(-4.3, @highline.ask_float(question))
assert_equal((question+' ')*6, @mock_io.output)
@mock_io.reset
@mock_io.input = [nil, '', "\n", ' ', "blah\n", "560\n"]
assert_equal(560.0, @highline.ask_float(question))
assert_equal((question+' ')*6, @mock_io.output)
end
def test_ask_float_range
question = 'Give me a floating point number between 5.0 and 13.5:'
@mock_io.input = [nil, '', "\n", ' ', "blah\n", " -4.3 \n", "4.9\n", "13.6\n", "7.55\n"]
assert_equal(7.55, @highline.ask_float(question, 5.0..13.5))
assert_equal((question+' ')*9, @mock_io.output)
end
def test_header
title = 'HighLine Manual'
@highline.header(title)
output = "-------------------\n| HighLine Manual
\n-------------------\n"
assert_equal(output, @mock_io.output)
end
def test_list
items = ['Ruby','Python','Perl']
prompt = 'Please choose your favorite programming language: '
@mock_io.input = [nil, "0\n", "blah\n", "4\n", "1\n"]
assert_equal(0, @highline.list(items, prompt))
assert_equal("1. Ruby\n2. Python\n3. Perl\n#{prompt * 5}", @mock_io.output)
end
end
end
