Testable_examples is a project mainly written in Ruby, it's free.
Test your examples!
Run your rdoc examples like they are tests!
In your rdoc, you might have something like this
# Example:
# Test1.new.add(1, 2)
# => 3
# Test1.new.add(1, "something")
# => TypeError: String can't be coerced into Fixnum
def add(num1, num2)
num1 + num2
end
With testable examples, simply add this to your Rakefile
desc "test_examples"
task :test do
$: << 'lib'
require 'testable_examples'
TestableExamples::Runner.new(:dir => 'lib', :include_path => 'lib', :requires => 'test1').run_examples
end
And you will now be able to validate these!
So much, this is really just a proof-of-concept.