   def flatten_lists_test
     [1,2,3] = [[1,2,3]].flatten_lists
     [1,2,3] = [[1],[2],[3]].flatten_lists
-    self.assert_error 'badarg, -> [1,2,3].flatten_lists
+    assert_error 'badarg, -> [1,2,3].flatten_lists
   end
 
   def each_test


  def zip_test
    [{'foo, 1}, {'bar, 2}] = ['foo, 'bar].zip([1, 2])
    self.assert_error 'function_clause, -> ['foo].zip([1, 2])
  end

  def unzip_test
    {['foo, 'bar], [1,2]} = [{'foo, 1}, {'bar, 2}].unzip
    self.assert_error 'function_clause, -> [{'foo, 0}, 'bar].unzip
  end

  def zipwith_test
    [5,7,9] = [1,2,3].zipwith([4,5,6], -> (x,y) x + y)
    self.assert_error 'function_clause, -> [1,2,3].zipwith([1,2], -> (_,_) 0)
  end

  def head_test
    1  = [1,2,3].head
    1  = [1].head
    self.assert_error 'badarg, -> [].head
  end

  def tail_test
    [2,3] = [1,2,3].tail
    [2] = [1,2].tail
    [] = [1].tail
    self.assert_error 'badarg, -> [].tail
  end

  def uniq_test

  end

  def fold_test
    addfun = -> (e, acc) e + acc
    "bazbarfoo" = ["foo", "bar", "baz"].foldl("", addfun)
    "foobarbaz" = ["foo", "bar", "baz"].foldr("", addfun)
  end

  def flatten_test
