no flatten flatten with same behavoir

gistfile1.txt

require 'minitest/autorun'
include MiniTest::Assertions

def arr_deep(arr)
  raise NoMethodError if (!arr.respond_to?(:to_a) or arr.nil?)
  arr.to_a.map do |q|
    if q.is_a?(Array)
      arr_deep(q)
    else
      q
    end
  end
end


class TestArrDeep < Minitest::Test
  def exception_class_for_flatten(sample)
    save_error = ZeroDivisionError
    begin
      s.flatten
    rescue Exception => e
      save_error = e.class
    end
    return save_error
  end

  def test_complex
    s = nil
    assert_raises exception_class_for_flatten(s) do
      arr_deep(s)
    end

    s = :a
    assert_raises exception_class_for_flatten(s) do
      arr_deep(s)
    end

    s = 1
    assert_raises exception_class_for_flatten(s) do
      arr_deep(s)
    end

    s = []
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Empty"

    s = {}
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Empty hash"

    s = {a:2}
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Hash"

    s = [1]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Simple"

    s = ["1"]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Simple string"

    s = [1, nil]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Simple, nil"

    s = [1, nil, :aa]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Simple, nil, sym"

    s = [[1,3,nil,[2]],{a:2},4]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Complex, hash, nil"

    s = [[1,3,nil,[2]],{a:2, b:4, :aa => 5},4]
    assert_equal arr_deep(s).join(", "), s.flatten.join(", "), "Complex, complex hash, nil"
  end
end