piglatin and rotation implemented in ruby

piglatin.rb

class String
  def vowel?
    match(/[aeiou]/i)
  end

	def constant?
		!match(/[aeiou]/i)
	end

	def rotate(n = 1)
		self[(n.remainder(length))..-1] + self[0..(n - 1)]
	end

	def rotate!
		self.replace(rotate)
	end

	def rotate_r(n = 1)
		self[-(n)..-1] + self[0..-(n.remainder(length) + 1)]
	end

	def rotate_r!
		self.replace(rotate_r)
	end

	def rotations
		r = []
		str = dup
		each do |_|
			r << str
			str.rotate!
		end
		r
	end

	def piglatin
		str = dup
		if str[0].vowel?
			str.rotate + 'ay'
		else
			str.rotate!.piglatin
		end
	end

end

require 'rspec'
RSpec.configure do |config|
	config.treat_symbols_as_metadata_keys_with_true_values = true

	config.expect_with :rspec do |c|
    c.syntax = :expect # disables `should`
end

describe 'String#vowel?' do
	it 'predicts a char is a vowel or not, ignore char case' do
		v = %w(a e i o u A E I O U f )
		c = %w(m n P Q)
    expect(v.map(&:vowel?).all?).to eq(true) # all true value in result
    expect(c.map(&:vowel?).any?).to eq(false) # no true value in result
end
end
describe 'String#constant?' do
	it 'predicts a char is a constant or not, ignore char case' do
		v = %w(a e i o u A E I O U )
		c = %w(m n P Q)
    expect(v.map(&:constant?).any?).to eq(false) # all true value in result
    expect(c.map(&:constant?).all?).to eq(true) # no true value in result
end