gistfile1.rb

require 'minitest/autorun'

BOOLEAN_MAPPINGS = {
  'true' => true,
  'false' => false
}

def typecast_hash_values(hash)
  hash.each do |k, old_value|
    if (new_value = BOOLEAN_MAPPINGS.fetch(old_value, old_value)) != old_value
      hash[k] = new_value
    end
  end
  hash
end

class TestBooleanHash < MiniTest::Unit::TestCase
  def setup
    @h = {_true: 'true', _false: 'false', _string: 'string'}
  end

  def test_typecast_hash_values
    typecast_hash_values(@h)

    assert_equal true, @h[:_true]
    assert_equal false, @h[:_false]
    assert_equal 'string', @h[:_string]
  end
end

require 'minitest/autorun'

BOOLEAN_MAPPINGS = {
  'true' => true,
  'false' => false
}

def typecast_hash_values(hash)
  hash.each do |k, old_value|
    hash[k] &&= hash[k] == 'true'
  end
  hash
end

class TestBooleanHash < MiniTest::Unit::TestCase
  def setup
    @h = {_true: 'true', _false: 'false', _string: 'string'}
  end

  def test_typecast_hash_values
    typecast_hash_values(@h)

    assert_equal true, @h[:_true]
    assert_equal false, @h[:_false]
    assert_equal 'string', @h[:_string]
  end
end

Run options: --seed 45169

# Running tests:

F

Finished tests in 0.016739s, 59.7407 tests/s, 179.2222 assertions/s.

  1) Failure:
test_typecast_hash_values(TestBooleanHash) [/Users/ka8725/projects/t.rb:25]:
Expected: "string"
  Actual: false