require 'edgecase'

class AboutHashes < EdgeCase::Koan
  def test_creating_hashes
    empty_hash = Hash.new
    assert_equal Hash, empty_hash.class
    assert_equal({}, empty_hash)
    assert_equal __, empty_hash.size
  end

  def test_hash_literals
    hash = { :one => "uno", :two => "dos" }
    assert_equal __, hash.size
  end

  def test_accessing_hashes
    hash = { :one => "uno", :two => "dos" }
    assert_equal __, hash[:one]
    assert_equal __, hash[:two]
    assert_equal __, hash[:doesnt_exist]
  end

  def test_changing_hashes
    hash = { :one => "uno", :two => "dos" }
    hash[:one] = "eins"

    expected = { :one => __, :two => "dos" }
    assert_equal expected, hash

    # Bonus Question: Why was "expected" broken out into a variable
    # rather than used as a literal?
  end

  def test_hash_is_unordered
    hash1 = { :one => "uno", :two => "dos" }
    hash2 = { :two => "dos", :one => "uno" }

    assert_equal hash1, hash2    
  end

 def test_hash_keys_and_values
    hash = { :one => "uno", :two => "dos" }

    assert_equal __, hash.keys.size
    assert_equal __, hash.has_key?(:one)

    # Why not just compare hash.keys to [:one, :two]?
    #
    # Clue: What was the name of the previous test again?

    assert_equal __, hash.values.sort
  end

  def test_combining_hashes
    hash = { "jim" => 53, "amy" => 20, "dan" => 23 }
    new_hash = hash.merge({ "jim" => 54, "jenny" => 26 })

    assert_not_equal hash, new_hash
    
    expected = { "jim" => __, "amy" => 20, "dan" => 23, "jenny" => __ }
    assert_equal expected, new_hash
  end
end