Expects a word and an array of possible anagrams of that word. Returns an array of all true anagrams.

anagram.rb

def anagrams(word, possible_anagrams)
  unless possible_anagrams.is_a?(Array) || possible_anagrams.all? { |anagram| anagram.is_a?(String) }
    raise TypeError.new("The possible anagrams must be an array")
  end

  possible_anagrams.find_all do |anagram|
    word.chars.sort == anagram.chars.sort
  end
end

anagram_spec.rb

require 'rspec'
require 'anagrams'

describe 'anagrams' do
  it 'finds a simple match' do
    anagrams("abc", ["cba"]).should eq ["cba"]
  end

  it 'finds all anagrams of a word from the list' do
    anagrams("abc", ["cba", "bca", "abc", "ac", "adc"]).should eq ["cba", "bca", "abc"]
  end

  it 'raises an exception if it does not get a string' do
    expect { anagram(2) }.to raise_exception
  end

  it 'raises an exception if it does not get an array of strings for the second arguement' do
    expect { anagram("abc", [2, 3, 4]) }.to raise_exception
    expect { anagram("abc", "abc") }.to raise_exception
  end
end