require 'test/unit'

module Test
  module Unit
    # TestSuite loads a default test if the suite is empty, whose purpose is to
    # fail. Since having empty contexts is a common practice, we decided to
    # overwrite TestSuite#empty? in order to allow them. Having a failure when no
    # tests have been defined seems counter-intuitive.
    class TestSuite
      def empty?
        false
      end
    end

    # Contest adds +teardown+, +test+ and +context+ as class methods, and the
    # instance methods +setup+ and +teardown+ now iterate on the corresponding
    # blocks. Note that all setup and teardown blocks must be defined with the
    # block syntax. Adding setup or teardown instance methods defeats the purpose
    # of this library.
    class TestCase
      def self.setup(&block)
        define_method :setup do
          super(&block)
          instance_eval(&block)
        end
      end

      def self.teardown(&block)
        define_method :teardown do
          instance_eval(&block)
          super(&block)
        end
      end

      def self.context(name, &block)
        subclass = Class.new(self)
        remove_tests(subclass)
        subclass.class_eval(&block) if block_given?
        const_set(context_name(name), subclass)
      end

      def self.test(name, &block)
        define_method(test_name(name), &block)
      end

      class << self
        alias should test
        alias describe context
      end

      def self.context_name(name)
        :"Test#{sanitize_name(name).gsub(/(^| )(\w)/) { $2.upcase }}"
      end

      def self.test_name(name)
        :"test_#{sanitize_name(name).gsub(/\s+/, '_')}"
      end

      def self.sanitize_name(name)
        name.gsub(/\W+/, ' ').strip
      end

      def self.remove_tests(subclass)
        subclass.public_instance_methods.grep(/^test_/).each do |meth|
          subclass.send(:undef_method, meth.to_sym)
        end
      end
    end
  end
end
