如何使用RSpec模拟/存根文件及其内容的目录?

不久前我问 How to test obtaining a list of files within a directory using RSpec? “虽然我得到了一些有用的答案,但我仍然被困在这里,因此我提出了一个新问题,其中有一些关于我要做什么的细节。

files = Foo.bar :directory => './public'

我已经编写了我的待定RSpec示例,但我真的不知道如何实现它们:

it "should compute a hash of the files within the specified directory"
it "shouldn't include hidden files or directories within the specified directory"
it "should compute a different hash if the content of a file changes"

以及它们的内容 ? gem实现将使用 Find.find ,但正如我另一个问题的答案之一所说,我不需要测试库。

我真的不知道如何写这些规格,所以任何帮助非常感谢!

编辑 :的 cache 下面的方法是我尝试测试的方法:

require 'digest/md5'
require 'find'

module Manifesto   
  def self.cache(options = {})
    directory = options.fetch(:directory, './public')
    compute_hash  = options.fetch(:compute_hash, true)
    manifest = []
    hashes = ''
    Find.find(directory) do |path|

      # Only include real files (i.e. not directories, symlinks etc.)
      # and non-hidden files in the manifest.
      if File.file?(path) && File.basename(path)[0,1] != '.'
        manifest << "#{normalize_path(directory, path)}\n"
        hashes += compute_file_contents_hash(path) if compute_hash
      end
    end

    # Hash the hashes of each file and output as a comment.
    manifest << "# Hash: #{Digest::MD5.hexdigest(hashes)}\n" if compute_hash
    manifest << "CACHE MANIFEST\n"
    manifest.reverse
  end

  # Reads the file contents to calculate the MD5 hash, so that if a file is
  # changed, the manifest is changed too.
  def self.compute_file_contents_hash(path)
    hash = ''
    digest = Digest::MD5.new
    File.open(path, 'r') do |file|
      digest.update(file.read(8192)) until file.eof
      hash += digest.hexdigest
    end
    hash
  end

  # Strips the directory from the start of path, so that each path is relative
  # to directory. Add a leading forward slash if not present.
  def self.normalize_path(directory, path)
    normalized_path = path[directory.length,path.length]
    normalized_path = '/' + normalized_path unless normalized_path[0,1] == '/'
    normalized_path
  end      
end