Lab 2: Mixins

Objectives

During this lab session:

Students will write a Ruby mixin and the corresponding unit tests.

This activity helps students develop the following skills, values and attitudes: ability to analyze and synthesize, capacity for identifying and solving problems, and efficient use of computer systems.

Activity Description

This lab can be developed individually or in pairs.

Take a glance at the documentation for Ruby's Enumerable module. This information will come in handy in a later step.
Create a folder called deque_mixin. Inside this folder, create two files called deque_mixin.rb and test_deque_mixin.rb.

Both Ruby source files must start with a comment containing the lab's title, date, and the authors' personal information. For example:
```
# Lab 2: Mixins
# Date: 27-Aug-2009
# Authors:
# 456654  Anthony Stark 
# 1160611 Thursday Rubinstein
```

The following is one possible implementation of the Deque class you wrote for last week's lab (copy this code into the deque_mixin.rb file):

class Deque  
    
  def initialize *elements
    @info = elements
  end
  
  def push_back x
    @info.push x
    self    
  end
  
  def push_front x
    @info.unshift x
    self
  end
  
  def pop_back
    @info.pop
  end
  
  def pop_front
    @info.shift
  end
  
  def back
    @info.last
  end
  
  def front
    @info.first
  end
  
  def empty?
    @info.empty?
  end
  
  def length
    @info.length
  end
  
  alias size length
      
  def inspect
    "front -> #{ @info.inspect } <- back" 
  end
  
end

You must mixin the Enumerable module into the Deque class. Make sure to provide a correct implementation of the each method.

In the test_deque_mixin.rb file, write a test case class that verifies that the following Enumerable methods works as described in the documentation: all?, any?, collect (alias map), detect (alias find), each_with_index, find_all (alias select), grep, include? (alias member?), inject, max, min, reject, sort, sort_by, to_a (alias entries), and zip.

Deliverables

To hand in your lab work, follow these instructions:

Create a ZIP file with the full contents of the deque_mixin directory. Call this file deque_mixin.zip.
Using the Online Assignment Delivery System (SETA), deliver the ZIP file. Due date is Friday, August 28.

Evaluation

This activity will be evaluated using the following criteria:

100	The code works as requested.
60-90	The code works, but has some flaws.
20-50	The code doesn't work, but it seams that some amount of time was spent on it.
DA	The program was plagiarized.

Software Design and Architecture

Lab 2: Mixins

Objectives

Activity Description

Deliverables

Evaluation