Code Kata: Cache

cache.rb

class Cache
end

run.rb

require './cache.rb'

cache = Cache.new

tests = [
  Proc.new do |cache|
    cache.get(:foo).nil?
  end,

  Proc.new do |cache|
    cache.set(:foo, 'FOO') == 'FOO'
  end,

  Proc.new do |cache|
    cache.set(:foo, 'FOO')
    cache.get(:foo) == 'FOO'
  end,

  Proc.new do |cache|
    cache.set(:foo, 'FOO')
    cache.delete(:foo) == 'FOO'
  end,

  Proc.new do |cache|
    cache.set(:foo, 'FOO')
    cache.delete(:foo)
    cache.get(:foo).nil?
  end,

  Proc.new do |cache|
    num_calls   = 0
    calculation = -> { num_calls += 1 }

    cache.fetch(:foo, &calculation) == 1 && cache.fetch(:foo, &calculation) == 1
  end,

  Proc.new do |cache|
    now         = Time.now
    expires_at  = now + 100

    cache.set(:foo, 'FOO', expires_at: expires_at)
    cache.get(:foo) == 'FOO'
  end,

  Proc.new do |cache|
    now         = Time.now
    expires_at  = now - 1

    cache.set(:foo, 'FOO', expires_at: expires_at)
    cache.get(:foo).nil?
  end,

  Proc.new do |cache|
    now         = Time.now
    expires_at  = now + 1

    cache.set(:foo, 'FOO', expires_at: expires_at)
    sleep(1.2)
    cache.get(:foo).nil?
  end,
]

tests.each_with_index do |test, i|
  print "Test #{i}: "

  begin
    if test.call(cache)
      puts 'success'
    else
      puts 'fail'
    end
  rescue StandardError => exception
    puts "error: #{exception.inspect}"
  end
end