在尝试模拟Hash Elements的gets和puts时,RSpec无法定义单例错误

class Book

  attr_accessor :books  
  def initialize books
    puts "Welcome to setting book price program"
    @books = books
  end

  def get_prices
    puts "Please enter appropriate price for each book item:-"
    count = 0
    @books = @books.inject({}) { |hash,book|
      print "#{book.first}: "
      price = STDIN.gets.chomp
      while (price !~ /^[1-9]d*$/ && price != "second hand")
        puts "Price can't be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate price in integer"
        price = STDIN.gets.chomp #gets.chomp - throws error
      end
      price == "second hand" ? price = "100" : price #takes a default price
      hash[book.first] = price.to_i
      hash
    }
  end

end

books = {"The Last Samurai" => nil,"Ruby Cookbook" =>  nil,"Rails Recipes" =>  nil,"Agile Development with Rails" =>  nil,"Harry Potter and the Deathly Hallows" =>  nil}


book_details = Book.new(books)
book_details.get_prices
puts "n*******Books Details:#{book_details.books}******n"

我正在尝试编写一个测试用例,检查每个图书项目的正确价格输入.如果价格输入不当,则应要求用户重新输入价格.该计划做得很好.但是当我尝试使用RSpec模拟这种行为时,我遇到了困难.

require 'spec_helper'

describe Book do

  before :each do
    books = {"The Last Samurai" => nil,"Harry Potter and the Deathly Hallows" =>  nil}
    @book = Book.new(books)
  end

  describe "#new" do
    it "Should be an instance of the Book" do
      @book.should be_an_instance_of Book
    end
  end

  describe "#getprice" do
    it "Should get the price in the correct format or else return appropriate error" do
      puts "n************************************************************************n"
      book_obj = @book
      STDOUT.should_receive(:puts).and_return("Welcome to setting book price program")
      book_obj.get_prices.should_not be_nil
      book_obj.books["The Last Samurai"].stub!(:gets) {"40"} #trying to set the value for one book using Hash
      book_obj.books["The Last Samurai"].should == 40 #verifying the value set for a particular key is accurate
    end
  end

end

你甚至可以从Github clone this code尝试这个.我使用的是Ruby 1.9.3和rspec 2.11.0

The error that I'm getting currently is:-

Failures:

  1) Book#getprice Should get the price in the correct format or else return appropriate error
     Failure/Error: book_obj.books["The Last Samurai"].stub!(:gets) {"40"} #trying to set the value for one book using Hash
     TypeError:
       can't define singleton
     # ./spec/book_spec.rb:31:in `block (3 levels) in <top (required)>'

Finished in 7.61 seconds
2 examples,1 failure

Failed examples:

rspec ./spec/book_spec.rb:21 # Book#getprice Should get the price in the correct format or else return appropriate error

更新的问题

对于糟糕的用户输入,使用以下测试用例我收到以下错误.我怎样才能正确处理这个？我尝试了几种选择,但它们似乎都失败了.请参阅规范代码段中每个选项的注释.

it "Incorrect input format should return error message asking user to re input" do
      puts "n************************************************************************n"
      book_obj = @book
      STDIN.stub(:gets) { "40abc" }

      #book_obj.get_prices.should be_nil --> adding this line of code goes into an infinite loop with the error message below
      #Price cannot be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate duration in integern

      STDOUT.should_receive(:puts).and_return("Price cannot be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate duration in integern")

      #the below two tests fails with syntax error - don't seem that easy to figure out what's going wrong

      #STDOUT.should_receive("Price cannot be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate duration in integern")
      #STDOUT.should == "Price cannot be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate duration in integern"
    end


Failures:

  1) Book#getprice Incorrect input format should return error message asking user to re input
     Failure/Error: STDOUT.should_receive(:puts).and_return("Price cannot be 0 or a negative integer or in decimal format or alphanumeric. nPlease input appropriate duration in integern")
       (#<IO:0x00000001c7b298>).puts(any args)
           expected: 1 time
           received: 0 times
     # ./spec/book_spec.rb:40:in `block (3 levels) in <top (required)>'

我真的很感激任何指导如何做到这一点.谢谢.