Tiny framework for one-line tests in Test::Unit

gistfile1.rb

# Tiny framework for writing one-line tests. Just call expect with a block. The
# block evaluates to true if the test passes and false if it doesn't.
#
# Example:
#   class ExpectTest < Test::Unit::TestCase
#     include Expect
#
#     expect { 1 == 1 }
#     expect { 1 == 2 }
#   end
#
# Output:
#   Loaded suite expect_test
#   Started
#   .F
#   Finished in 0.00058 seconds.
#   
#     1) Failure:
#   test: (1 == 2) (SomeTest) [./expect.rb:20]:
#   expected (1 == 2)
#   
#   2 tests, 2 assertions, 1 failures, 0 errors

require 'rubygems'
require 'parse_tree'
require 'ruby2ruby'

module Expect
  def self.last_statement_in_block(&block)
    temp_class = Class.new
    temp_class.module_eval do
      define_method :block_method, &block
    end
    block_contents = Ruby2Ruby.translate(temp_class, :block_method).split("\n")
    block_contents.pop
    block_contents.last.gsub!(/^  /, '')
  end

  def self.included(base)
    def base.expect(&block)
      s = Expect.last_statement_in_block(&block)
      define_method("test: #{s} ".to_sym) do
        assert_block("expected #{s}", &block)
      end
    end
  end
end