koans/about_symbols.rb

   1 require File.expand_path(File.dirname(__FILE__) + '/edgecase')
   2
   3 class AboutSymbols < EdgeCase::Koan
   4   def test_symbols_are_symbols
   5     symbol = :ruby
   6     assert_equal __, symbol.is_a?(Symbol)
   7   end
   8
   9   def test_symbols_are_not_strings
  10     symbol = :ruby
  11     assert_equal __, symbol.is_a?(String)
  12     assert_equal __, symbol.eql?("ruby")
  13   end
  14
  15   def test_symbols_have_unique_identity
  16     symbol1 = :identity
  17     symbol2 = :identity
  18     symbol3 = :something_else
  19
  20     assert symbol1 == __
  21     assert symbol1 != __
  22   end
  23
  24   def test_identical_symbols_are_represented_by_a_single_internal_object
  25     symbol1 = :identity
  26     symbol2 = :identity
  27
  28     assert symbol1.equal?(__)
  29     assert_equal __, symbol2.object_id
  30   end
  31
  32   def test_method_names_become_symbols
  33     all_symbols = Symbol.all_symbols
  34
  35     assert_equal __, all_symbols.include?(:test_method_names_are_symbols)
  36   end
  37
  38   RubyConstant = "This string is assigned to a constant."
  39   def test_constants_become_symbols
  40     all_symbols = Symbol.all_symbols
  41
  42     assert_equal true, all_symbols.include?(__)
  43   end
  44
  45   def test_symbols_can_be_made_from_strings
  46     string = "catsAndDogs"
  47     assert_equal __, string.to_sym
  48   end
  49
  50   def test_symbols_with_spaces_can_be_built
  51     symbol = :"cats and dogs"
  52
  53     assert_equal symbol, __.to_sym
  54   end
  55
  56   def test_interpolated_symbols_become_strings
  57     symbol = :cats
  58     string = "It is raining #{symbol} and dogs."
  59
  60     assert_equal __, string
  61   end
  62
  63   def test_symbols_cannot_be_concatenated
  64     assert_raise(__) do
  65       :cats + :dogs
  66     end
  67   end
  68 end