Paddock Equality

paddock.rb

# In this example case when we create paddock objects we want them to be equal
# to each other if their name and area are the same and their lat/lng are "close
# enough" to each other. In our case we want "close enough" to mean the lat and
# lng match up to four decimal places.
#
# Download this file and the corresponding test case file tc_paddock.rb. Run the
# test case file like this `ruby tc_paddock.rb`. Currently all tests fail.

# Please make the changes you feel are necessary to make the tests pass, then
# make a gist with your version of paddock.rb and let us know.

class Paddock
  attr_accessor :lat, :lng, :name, :area
  PRECISION = 4

  #
  # redefine lat and lng as round value by 4 decimal places precision
  # also leave name and area set by their value each as default
  #
  def initialize(lat:, lng:, name:, area:)
    self.lat = equalizeValueOf lat
    self.lng = equalizeValueOf lng
    self.name = name
    self.area = area
  end

  #
  # redefine '==', by comparing each attributes with double equals method
  #
  def ==(other)
    self.lat == equalizeValueOf(other.lat) && self.lng == equalizeValueOf(other.lng) && self.name == other.name && self.area == other.area
  end

  #
  # redefine 'eql?', by comparing each attributes with 'eql?' method
  #
  def eql?(other)
    self.lat.eql?(equalizeValueOf(other.lat)) && self.lng.eql?(equalizeValueOf(other.lng)) && self.name.eql?(other.name) && self.area.eql?(other.area)
  end

  #
  # Override hash for check object uniq in array
  # Ref: https://www.ruby-forum.com/topic/165653
  #
  def hash
    [lat, lng, name, area].hash
  end

  #
  # checking the value of the lat and lng then redefine
  # if the value is float, then it will make lat and lng value equal to rounded by 4 decimal places precision
  #
  def equalizeValueOf(value)
    case value.class
      when Fixnum then value
      when Float then value.round(PRECISION).to_f
    end
  end
end

tc_paddock.rb

require 'test/unit'
require_relative 'paddock'

class TestPaddock < Test::Unit::TestCase
  def setup
    @p1 = Paddock.new(lat: -31.9415, lng: 115.8418, name: 'Agworld HQ', area: 10)
    @p2 = Paddock.new(lat: -31.94154, lng: 115.84183, name: 'Agworld HQ', area: 10)
    @p3 = Paddock.new(lat: -31.9405, lng: 115.8408, name: 'Agworld HQ', area: 11)
    @p4 = Paddock.new(lat: -31.9415, lng: 115.8418, name: 'Agworld Branch', area: 10)
  end

  def test_double_equals
    assert(@p1 == @p2, 'p1 should == p2')
    assert_equal(@p1 == @p3, false, 'p1 should not == p3')
    assert_equal(@p1 == @p4, false, 'p1 should not == p4')
  end

  def test_eql?
    assert(@p1.eql?(@p2), 'p1 should eql? p2')
    assert_equal(@p1.eql?(@p3), false, 'p1 should not eql? p3')
  end

  def test_uniq
    assert_equal([@p1, @p2].uniq.length, 1)
    assert_equal([@p1, @p3].uniq.length, 2)
  end
end