if_syntax_is_your_concern.rb

module Test
  module Unit
    TestCase = RSpec::Core::ExampleGroup
  end
end

class Test::Unit::TestCase
  def self.inherited(host)
    host.set_it_up host.name.gsub(/(Spec|Test)/,'')
    def host.method_added(name)
      if name.to_s =~ /^test_/
        specify name do
          send name
        end
      end
      super
    end
    host.register
  end
end

RSpec.configure do |config|
  config.expect_with :stdlib
end

# With the above hax + standard RSpec configuration options, we now
# have test/unit syntax.

class TestFive < Test::Unit::TestCase
  def test_it_equals_five
    assert_equal 5,5
  end
end

# Now that syntax is out of the way, here are some things you get from RSpec
# that you don't get from Test/Unit
#
#################################
# Readable output
#
# $ rspec example_spec.rb -fd
# 
# Five
#   test_it_equals_five
# 
# Finished in 0.0006 seconds
# 1 example, 0 failures
#
#################################
# Pending examples
#
# class TestFive < Test::Unit::TestCase
#   def test_it_equals_five
#     pending
#     assert_equal 5,5
#   end
# end
# $ rspec example_spec.rb -fd
# 
# Five
#   test_it_equals_five (PENDING: No reason given)
# 
# Pending:
#   Five test_it_equals_five
#     # No reason given
#     # ./example_spec.rb:12
# 
# Finished in 0.00052 seconds
# 1 example, 0 failures, 1 pending
# 
#################################
# Pending examples that tell you when they don't need to be pending any longer
# because the block content passes (AFAIK, Rails' implementation of pending
# doesn't support this):
# 
# class TestFive < Test::Unit::TestCase
#   def test_it_equals_five
#     pending do
#       assert_equal 5,5
#     end
#   end
# end
# 
# $ rspec example_spec.rb -cfd
# 
# Five
#   test_it_equals_five (FAILED - 1)
# 
# Failures:
# 
#   1) Five test_it_equals_five FIXED
#      Expected pending 'No reason given' to fail. No Error was raised.
#      # ./example_spec.rb:32:in `test_it_equals_five'
#      # ./example_spec.rb:13:in `send'
#      # ./example_spec.rb:13:in `method_added'
# 
# Finished in 0.00054 seconds
# 1 example, 1 failure
# 
## Run one test method by its line number:
# 
# $ rspec example_spec.rb:30
# Run filtered using {:line_number=>30}
# .
# 
# Finished in 0.00043 seconds
# 1 example, 0 failures
#
#################################
# Profile mode: lists the top 10 slowest examples
#
# $ rspec example_spec.rb -p
# .
# 
# Top 1 slowest examples:
#   Five test_it_equals_five
#     0.00016 seconds ./example_spec.rb:12
# 
# Finished in 0.00038 seconds
# 1 example, 0 failures
#
# And much, much more. And all of this is without even using any of RSpec's syntax.
# If you add this bit of configuration:

RSpec.configure do |c|
  c.alias_example_to :test
end

# Now you can use strings for test names, just like Rails does! But, what
# neither Test/Unit nor Rails t/u extensions let you do is add metadata to the
# examples:

class TestTaggingExamples < Test::Unit::TestCase
  test "example that runs fast", :fast => true do
    # ...
  end

  test "example that runs slow", :slow => true do
    # ...
  end
end

# Now you can run the fast examples like this:
#
# $ be rspec example_spec.rb --tag fast --format doc
# Run filtered using {:fast=>true}
# 
# TaggingExamples
#   example that runs fast
# 
# Finished in 0.00037 seconds
# 1 example, 0 failures
#
# ... and you can run the slow examples like this:
#
# $ rspec example_spec.rb --tag slow --format doc
# Run filtered using {:slow=>true}
# 
# TaggingExamples
#   example that runs slow
# 
# Finished in 0.0004 seconds
# 1 example, 0 failures
#
# The tag names are arbitrary and you can use them to organize examples any way
# you like, and run subsets of them at will.
#
#################################
#
# The above is just the tip of the iceberg, but hopefully helps to show that
# there is more to RSpec than its syntax.

I love it! :)