Ruby Flatten

README.md

RubyFlatten README

This program is a clone of the Ruby method "Flatten".
It may be cloned from the source repository at https://github.com/Ryanspink1/ruby_flatten

Testing:

This application uses Minitest for testing, please make sure it's installed.
To test from root directory, type "ruby test/flatten_test.rb" into terminal

Will output 12 runs, 20 assertions

Running application in terminal:

Program will only accept a single array of integers in any combination of arrays.

Program will output a single flattened array of integers in the order in which they appeared in the input array.

From program root directory in terminal:

1. irb
2. require './lib/flatten'
   
3. RubyFlatten.start(input_array)

flatten.rb

class RubyFlatten
  attr_reader :output

  def initialize
    @output = []
  end

  def self.start(input)
    c = RubyFlatten.new
    c.check_input_type(input)
    c.flatten_this(input)
    c.output
  end

  def flatten_this(input)
    input.each {|n| check_for_array(n)}
  end

  def check_for_array(n)
    if n.class == Array
      flatten_this(n)
    else
      check_output_type(n)
      output << n
    end
  end

  def check_input_type(input)
    raise("Input not an array") if input.class != Array
  end

  def check_output_type(input)
    raise("Input not an integer") if input.class != Integer
  end
end

flatten_test.rb

require 'minitest/autorun'
require 'minitest/pride'
require './lib/flatten'

class FlattenTest < Minitest::Test
  attr_reader :output

  def setup
    @output = RubyFlatten.start([1,[2,[3,[4,5]]],6,[7,8]])
  end

  def test_will_not_accept_string
    assert_raises("Input not an array") {RubyFlatten.start("Bad Input")}
  end

  def test_will_not_accept_hash
    assert_raises("Input not an array") {RubyFlatten.start({"Bad Input": true})}
  end

  def test_will_not_accept_lone_integer
    assert_raises("Input not an array") {RubyFlatten.start(1)}
  end

  def test_will_not_accept_lone_float
    assert_raises("Input not an array") {RubyFlatten.start(1.23)}
  end

  def test_accepts_negative_integers
    expected = [1,-2,3,4,-5,6,7,8]
    output   = RubyFlatten.start([1,[-2,[3,[4,-5]]],6,[7,8]])
    assert_equal expected, output
  end

  def test_output_not_nil
    expected = output.nil?
    assert_equal false, expected
  end

  def test_output_not_empty
    expected = output.empty?
    assert_equal false, expected
  end

  def test_output_is_an_array
    expected = output.class
    assert_equal Array, expected
  end

  def test_each_index_is_an_integer
    output.each do |index|
      output_class = index.class
      assert_equal Integer, output_class
    end
  end

  def test_output_count
    count = output.count
    assert_equal 8, count
    assert_equal false, output.count == 3
  end

  def test_output_is_correct
    expected = [1,2,3,4,5,6,7,8]
    assert_equal expected, output
  end

  def test_output_is_not_random
    assert_equal false, output == [8,7,3,4,1,2,6,5]
  end
end