Question

I would have expected the answer for both of the koans below to be

:default_value

but the correct answer is apparently :false_value.

In the first one, I understand the unless statement to mean,

result = :false_value but not if the control statement is false. 

Since the control statement is ‘false’ i.e unless false, result should therefore be :default_value. Same thing for the second koan.

Please explain

def test_unless_statement
    result = :default_value
    unless false
      result = :false_value
    end
    assert_equal __, result
  end

  def test_unless_statement_modifier
    result = :default_value
    result = :false_value unless false

    assert_equal __, result
  end

Answer 1

In both cases, the correct answer is :false_value. You can think of it this way:

unless means if !(...)

unless false means if !(false) which means if true

Or just note that the double negatives cancel each other out.