Flatten

flatten_spec.rb

#Michael Hamrah

require 'rspec'

def flatten(input)
  array = []

    input.each { |x| (x.respond_to? :each) ? array.concat(flatten(x)) : array.push(x) }

  array
end

describe "Flatten" do
  it "returns an array with the same items as input" do
    data = [3, 2, 1]

    result = flatten(data)

    result.count.should == data.count

    result.should include(data[0])

  end

  it "can flatten an array containing multiple arrays" do
    data = [[1, 2], 3, [4, 5, 6], 7]

    result = flatten(data)

    result.count.should == 7
    result.should include(2)
    result.should include(7)

  end

  it "can flatten multiple nested arrays" do
    data = [1, [2, [3, 4], 5], 6, 7]

    result = flatten(data)

    result.count.should == 7

    result.should include(4)
    result.should include(5)
    result.should include(7)

  end
end