module Test
  module Unit
    module Given
      # A simple form that doesn't enforce the use of 
      # Given/When/Then.  This is merely to make it clear
      # which parts of your test do what
      module Simple
        # Public: Set up the conditions for the test
        #
        # existing_block - a callable object (e.g. a Proc) that will be called immediately
        #                  by this Given.  If nil, &block is expected to be passed
        # block          - a block given to this call that will be executed immediately
        #                  by this Given.  If existing_block is non-nil, this is ignored
        #
        # Examples
        #     
        #     given_block = Given {
        #       @foo = "bar"
        #     }
        #     # => executes block and returns it
        #     Given given_block
        #     # => executes the block again
        #
        # Returns the block that was executed
        def Given(existing_block=nil,&block)
          call_block_param_or_block_given(existing_block,&block)
        end
        # Public: Execute the code under test
        #
        # existing_block - a callable object (e.g. a Proc) that will be called immediately
        #                  by this When.  If nil, &block is expected to be passed
        # block          - a block given to this call that will be executed immediately
        #                  by this When.  If existing_block is non-nil, this is ignored
        #
        # Examples
        #     
        #     when_block = When {
        #       @foo.go
        #     }
        #     # => executes block and returns it
        #     When when_block
        #     # => executes the block again
        #
        # Returns the block that was executed
        def When(existing_block=nil,&block)
          Given(existing_block,&block)
        end

        # Public: Verify the results of the test
        #
        # existing_block - a callable object (e.g. a Proc) that will be called immediately
        #                  by this Then.  If nil, &block is expected to be passed
        # block          - a block given to this call that will be executed immediately
        #                  by this Then.  If existing_block is non-nil, this is ignored
        #
        # Examples
        #     
        #     then_block = Then {
        #       assert_equal "bar",@foo
        #     }
        #     # => executes block and returns it
        #     Then then_block
        #     # => executes the block again
        #
        # Returns the block that was executed
        def Then(existing_block=nil,&block)
          Given(existing_block,&block)
        end

        # Public: Continue the previous Given/When/Then in a new block.  The reason
        # you might do this is if you wanted to use the existing block form of a
        # Given/When/Then, but also need to do something custom.  This allows you to 
        # write your test more fluently.
        #
        # existing_block - a callable object (e.g. a Proc) that will be called immediately
        #                  by this Then.  If nil, &block is expected to be passed
        # block          - a block given to this call that will be executed immediately
        #                  by this Then.  If existing_block is non-nil, this is ignored
        #
        # Examples
        #     
        #     then_block = Then {
        #       assert_equal "bar",@foo
        #     }
        #     # => executes block and returns it
        #     Then then_block
        #     And {
        #       assert_equal, "quux",@blah
        #     }
        #     # => executes the block again
        #
        # Returns the block that was executed
        def And(existing_block=nil,&block)
          Given(existing_block,&block)
        end

        # Public: Continue the previous Given/When/Then in a new block.  The reason
        # you might do this is if you wanted to use the existing block form of a
        # Given/When/Then, but also need to do something custom, and that custom thing
        # contradicts or overrides the flow, so an "And" wouldn't read properly.  This allows you to 
        # write your test more fluently.
        #
        # existing_block - a callable object (e.g. a Proc) that will be called immediately
        #                  by this Then.  If nil, &block is expected to be passed
        # block          - a block given to this call that will be executed immediately
        #                  by this Then.  If existing_block is non-nil, this is ignored
        #
        # Examples
        #     
        #     given_block = Given {
        #       @options = {
        #         :foo => 'bar',
        #         :quux => 'baz',
        #       }
        #     }
        #     Given then_block
        #     And {
        #       @name = 'Foo'
        #     }
        #     But {
        #       @options[:quux] = 'BAZ'
        #     }
        #
        # Returns the block that was executed
        def But(existing_block=nil,&block)
          Given(existing_block,&block)
        end

        # Public: Used to make clear the structure of tests using mocks.
        # This returns a no-op, and is intended to be used with a "When"
        # to delineate the creation of a mock in a Given, and the 
        # expectations of a mock in a "Then"
        #
        # Example:
        #
        #     Given {
        #       @google = mock()
        #     }
        #     When test_runs
        #     Then {
        #       @google.expects(:search).with('foo').returns('bar')
        #     }
        #     Given {
        #       @my_search = Search.new(@google)
        #     }
        #     When {
        #       @result = @my_search.find('foo')
        #     }
        #     Then {
        #       assert_equal 'Found bar',@result
        #     }
        #     And mocks_shouldve_been_called
        def test_runs
          lambda {}
        end

        # Similar to #test_runs, this is used to make clear what
        # you are testing and what the assertions are.  Since many Ruby mock
        # frameworks do not require an explicit "verify" step, you often have tests
        # that have no explicit asserts, the assertions being simply that the mocks were called
        # as expected.  This step, which is a no-op, allows you to document that you are 
        # expecting mocks to be called. See the example in #mocks_are_called for usage.
        def mocks_shouldve_been_called
          lambda {}
        end

        private

        def call_block_param_or_block_given(existing_block,&block)
          if existing_block.nil?
            block.call
            block
          else
            existing_block.call
            existing_block
          end
        end
      end
    end
  end
end