Remove duplicate words

remove_duplicate.rb

=begin
Your task is to remove all duplicate words from string, leaving only single words entries.

Example:

Input:

'alpha beta beta gamma gamma gamma delta alpha beta beta gamma gamma gamma delta'

Output:

'alpha beta gamma delta'
=end

def remove_duplicate_words(s)
  s.split(" ").reduce([]){|acc, c| acc.include?(c) ? nil : acc << c; acc }.join(" ") 
end

describe "Remove Duplicate Words" do
  Test.assert_equals(remove_duplicate_words("alpha beta beta gamma gamma gamma delta alpha beta beta gamma gamma gamma delta"), "alpha beta gamma delta")
  Test.assert_equals(remove_duplicate_words("my cat is my cat fat"), "my cat is fat")
end