RubySource Demo for Test Driving to Distraction

student_file.rb

class StudentLine

  def initialize(line)
    @line = line 
  end

  def full_name
    first_name << " " << second_name
  end

  def age
    @line[28..29]
  end

  def gender
    @line[30..-1].strip
  end

  private

  def first_name
    @line[14..27].strip
  end

  def second_name
    @line[0..13].strip
  end

end

class StudentFile

  attr_reader :class_name
    
  def initialize(lines, output=STDOUT)
    @class_name = lines.shift.strip
    @footer = lines.pop
    @lines = []

    lines.each do |line|
      @lines << StudentLine.new(line) if line.length > 33
    end

    @output = output
  end

  def self.parse(filename, output=STDOUT)
    f = File.new(filename)
    self.new(f.readlines, output)
  end

  def valid_file?
    (line_count == expected_line_count) && !line_count.zero?
  end

  def print
    if self.valid_file?
      @output.print formatted_output
    else
      @output.print "INVALID FILE"
    end
  end

  private

  def formatted_output
    [class_name.upcase, separator, header, separator, students, separator].join("\n")  
  end

  def header
    "| STUDENT                     | AGE | GENDER       |"
  end

  def separator
    "+-----------------------------+-----+--------------+"
  end

  def students
    row = []
    @lines.each do |line|
      row << ("| " << line.full_name.ljust(28) << "| "  << line.age.ljust(4) << "| " << line.gender.ljust(13) << "|")
    end
    row.join("\n")
  end  

  def line_count
    @lines.length
  end

  def expected_line_count
    @footer.to_i
  end
end

student_file_test.rb

require 'minitest/spec'
require 'minitest/autorun'
require 'stringio'

require './student_file'

describe StudentLine do

  before do
    @student = StudentLine.new("RABBIT        JESSICA       25FEMALE")
  end

  it "will return the name of the student" do
    @student.full_name.must_equal "JESSICA RABBIT"
  end

  it "will return the age of the student" do
    @student.age.must_equal "25"
  end

  it "should return the gender" do
    @student.gender.must_equal "FEMALE"
  end

end

describe StudentFile do

  describe "parse" do
    it "will return an instance of StudentFile" do
      StudentFile.parse('test_file.txt').must_be_kind_of(StudentFile)
    end
  end

  it "will return the correct class name" do
    valid_file.class_name.must_equal "Class Name"
  end

  it "will return true if the file is valid" do
    valid_file.valid_file?.must_be :==, true
  end

  it "will return false if the file is invalid" do
    invalid_file.valid_file?.must_be :==, false
  end

  describe "print" do
    before do
      @out = StringIO.new
    end

    it "will print pipe seperated classmate info" do
      valid_file(@out).print
      @out.string.must_be :==, expected_output.strip
    end

    it "will display error if file is invalid" do
      invalid_file(@out).print
      @out.string.must_be :==, "INVALID FILE"
    end
  end

end

def valid_file(op=STDOUT)
  StudentFile.new(["Class Name\n", "RABBIT        JESSICA       25FEMALE\n", "001\n"], op)
end

def invalid_file(op=STDOUT)
  StudentFile.new(["Class Name"], op)
end

def expected_output
  <<OUTPUT
CLASS NAME
+-----------------------------+-----+--------------+
| STUDENT                     | AGE | GENDER       |
+-----------------------------+-----+--------------+
| JESSICA RABBIT              | 25  | FEMALE       |
+-----------------------------+-----+--------------+
OUTPUT
end

test_file.txt

Test Unit 101
WIGGUM        RALF          13MALE  
COYOTE        WYLIE         72MALE  
RABBIT        JESSICA       25FEMALE
003