Lab 4: Refactoring

Objectives

During this lab session:

Students will refactor Ruby code and test it.

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

IMPORTANT NOTE: The lab activities can be developed individually or in pairs. The lab report must be developed individually.

Create a folder called refactoring. Inside this folder, create two files called student.rb and test_student.rb.

Both Ruby source files must start with a comment containing the lab's title, date, and the authors' personal information. For example:
```
# Lab 4: Refactoring
# Date: 15-Feb-2012
# Authors:
# 456654  Thursday Rubinstein
# 1160611 Anthony Stark
```

Place the following code in the file called student.rb:

# File: student.rb

class Student

  attr_reader :name, :id   
        
  def initialize(name, id, anual_income)
    @name = name 
    @id = id
    @anual_income = anual_income
    @grades = []        
  end
  
  def reset_anual_income(anual_income)
    previous_anual_income = @anual_income
    @anual_income = anual_income
    previous_anual_income
  end
  
  def add_grade(grade)
    @grades << grade
    self
  end
  
  def meh
    # Display Personal Information
    puts "Name: #{ @name } ID: #{ @id }"
    puts "Anual income: #{ @anual_income }"
    value = 0
    @grades.each do |grade|
      value += grade
    end
    value = value / @grades.size.to_f
    puts "Grade average: #{ value }"
        
    # Display Disclaimer
    puts 'The contents of this class must not be considered an offer,'
    puts 'proposal, understanding or agreement unless it is confirmed'
    puts 'in a document signed by at least five blood-sucking lawyers.'    
  end
  
  def scholarship_worthy?    
    # Nothing reasonable to do if this student has currently no grades. 
    return -1 if  @grades.empty?
    
    # A student is worthy of a scholarship if he/she has good grades and
    # is poor.
    value = 0
    @grades.each do |grade|
      value += grade
    end
    value = value / @grades.size.to_f
    (value >= 85) and (@anual_income < 15_000)    
  end      
  
end

In the test_student.rb file write a complete unit test class in order to thoroughly verify the current behavior of Student instances. Make sure to individually test the meh and scholarship_worthy? methods.

Modify the Student class so that you carry out the following refactorings as many times as you consider necessary:
Clearly state in your lab report how the code looked before and after the refactoring.

Rerun (and adjust if necessary) your unit tests to make sure that the refactorings didn't modify the class' external behavior.

Deliverables

To hand in your individual lab work, follow these instructions.

Write your lab report in English according to the specified guidelines. Name your AsciiDoc source file lab4_report_A0MMMMMMM.txt, where A0MMMMMMM is your student ID. From your AsciiDoc source, generate the corresponding HTML file. That file should be called lab4_report_A0MMMMMMM.html. Place these two files in the refactoring directory.
Create a tarball file with the full contents of the refactoring directory. Call this file refactoring.tgz. From a terminal, you can use the following command to create this file (make sure to run it at the same level where the refactoring folder resides):
```
tar czf refactoring.tgz refactoring
```
Using the Online Assignment Delivery System (SETA), deliver the tarball file.

Due date is Tuesday, February 21.

Evaluation

This activity will be evaluated using the following criteria:

50%	Implementation of functional requirements.
50%	Lab report.
DA	The program and/or report was plagiarized.

Software Design and Architecture

Lab 4: Refactoring

Objectives

Activity Description

Deliverables

Evaluation