My rspec fantasy

gistfile1.rb

# Here is a normal set of specs...

describe 'some normal rspec' do

  describe 'doing something with a Product and Users' do

    before :each do
      # setup etc

      # preconditions could go here
      User.count.should be > 5
      Product.all.any?{|p| p.discontinued?}.should be true
    end

    def dispatch
      @result = do_something with: [Product, User]
    end

    it 'should have called something' do
      # assertions before the fact without spies :(
      Api.should_receive(:some_message)
      dispatch
    end

    it 'uses an implicit return value when calling should' do
      dispatch.should == :returned_result_from_act
    end

    context 'doing that something with special options' do

      # runs the preconditions fom the outer describe and the following
      before :each do
        # more preconditions
      end

      def dispatch
        do_something with: [Product, User], some_special_option: true
      end

      it 'behaves differently somehow' do
        dispatch.should == :something_else
      end

    end
  end
end

# Here is how I would LIKE to write them ...

describe 'my rspec fantasy feature spies and some new api' do

  describe 'doing something with a Product and Users' do

    before :each do
      # setup etc
    end

    # these would run before all specs
    preconditions do
      precondition 'five users' { User.count.should be > 5 }
      precondition 'a discontinued product' { Product.all.any?{|p| p.discontinued?}.should be true }
    end

    act { do_something with: [Product, User] }

    it 'should have called something' do
      # assertions AFTER the fact
      Api.should have_received(:some_message)
    end

    it 'uses an implicit return value when calling should' do
      should == :returned_result_from_act
    end

    context 'doing that something with special options' do

      # runs the preconditions fom the outer describe and the following
      preconditions do
        preconditions 'etc' { }
      end

      # this act overrides the act in the outer describe block
      act { do_something with: [Product, User], some_special_option: true }

      it 'behaves differently somehow' do
        should == :something_else
      end

    end
  end
end

# Here's why:
#
# I like to use test spies rather than mock-expectations because then I can stay consistent with the xunit pattern
#
# * Arrange
# * Act
# * Assert
#
# This means that I can separate the different concerns in writing my specs and introduce preconditions:
#
# * Arrange the environment
# * Assert preconditions
# * Act
# * Assert postconditions
#
# Preconditions mean that the test runner can avoid unnecessarily running specs with failing preconditions and best of all, it means I can get rspec --doc output like this:
#
# my rspec fantasy
#   doing something with a Product and Users
#     precondition failed: 'five users'
#
# When this failure occurs I know exactly why my specs have not been run and what to do next to fix the suite. with
#
# it also provides a way to separate and DRY the ACT
# * it calls can be simple one-liners and only have one concern: assertion
# * the act can be defined ONCE and run implicitly
#
# this also means that I can start sketching out my specs by just writing the assertions and preconditions and worry about the arrange and act details later in the BDD process.
#
#
# Each syntax yields roughly the same number of lines in this small example. Larger examples may lead to fewer lines of code as a result of being DRYed up.
#
# Overall the benefits would be
# * clearer more consistently structured specs and...
# * better spec output leading to...
# * more maintainable spec suites
#