class Crispr::Mutations::String

def mutations_for(node)
  return [] unless node.is_a?(Parser::AST::Node)
  return [] unless node.type == :str
  original = node.children.first
  return [] unless original.is_a?(::String)
  mutations = []
  # Common string mutations
  mutations << s(:str, "")
  mutations << s(:str, "a")
  mutations << s(:str, "test")
  mutations << s(:str, original.reverse) unless original.empty?
  mutations << s(:str, original.upcase) unless original.upcase == original
  mutations << s(:str, original.downcase) unless original.downcase == original
  mutations << s(:str, "mutated")
  mutations << s(:nil)
  mutations
end