yet-another-ruby-iterator

• Iteration stop when all the element in each has already yielded the block
• The each method in class Triple yield all of it's arguments, and then return itself before exit

Installation

gem install bundler
bundle install

Run

After the installation, just type rspec to run the spec

File Structure

• All the implementations is in the lib folder, therefore, my implementation of the Enumerate module and the Triple class is in this folder.
• All the unit testing files are in the spec folder.
  • The spec_helper in spec folder is for Rspec to manage the test.
• Tree Structure of the file structure:

.
├── Gemfile
├── Gemfile.lock
├── README.md
├── lib
│   └── chichun_enum.rb
└── spec
    ├── chichun_enum_spec.rb
    └── spec_helper.rb

Notes

• RSpec is a tool for behavior driven test process, it allows developers to describe a sequences of actions, and build our test case in whatever situation
• Simple case of writing tests using RSpec:
  • Firstly, use the keyword describe to describe the method you'd like to test
  • And then use keyword context to indicate the current situation, such as:
    • Whether the method has argument
    • Whether the method get block as argument
  • Finally, write the unit tests in the it block
• The output hierarchy of RSpec
  • If unit tests is written in a context block, then the output of tests indent
  • Method all? and any? can both accept calling without block, therefore, I put the tests in the context block, and all of the unit tests inside the context block indent

#all?
  return true if all three elements in t > 0
  return false if one of the elements in t < 0
  when block not given
    return false if there are any elements that is nil
    return false if there are any elements that is false
    return true if there no elements that is false or nil

#any?
  returns true if there is one element greater than 0
  returns false since there is no elements in t greater than 0
  when block not given
    return true if there are any elements?
    return false if no any elements?

• All of the method I wrote in describe added # as prefix, which means it's not an instance method, an instance method should be write as .foo

Test of infinite loop

• From the ruby doc, if no argument is given or nil is given as an argument, then method cycle go into an infinite loop
• My way of testing infinite loop is to create a thread and then call cycle() or cycle(nil) inside that thread to make sure that the test is not blocked
• And then call sleep(x) in main thread to wait for the loop
  • x is an arbitrary time which is not too short for setting the loop flag, and not too long to block our test suite
• The body of the loop set a flag to indicate that while calling cycle, the program really go into the loop, after a arbitrary time, main thread kill the created thread, and test the flag

Implementation

• How to return Enumerator class if block not given
  • to_enum(:name_of_this_method, arg1, arg2, ..., argn) unless block_given?
• What if the Enumerator that we want to return is not the one that we can get from :each
  • Use Enumerator.new to create one
    • in the block of the creation, we call yield just like we do in each

Reference

• http://rspec.info/
• http://www.betterspecs.org/