Palindrome algorithm

palindrome.rb

def palindrome?(word)
  left = 0
  right = word.length - 1

  while left < right
    return false if word[left] != word[right]

    left += 1
    right -= 1
  end

  true
end

# Tests

require 'rspec/autorun'

describe 'palindrome?' do
  it 'returns true for a palindrome word' do
    expect(palindrome?("HANNAH")).to be true
  end

  it 'returns false for a non-palindrome word' do
    expect(palindrome?("GAGA")).to be false
  end
end