Add ability to include partial workflow definitions for composability

Author: dvanderbeek

lib/workflow/specification.rb

@@ -20,6 +20,10 @@ def state_names
 
     private
 
+    def include(proc)
+      instance_eval(&proc)
+    end
+
     def state(name, meta = {:meta => {}}, &events_and_etc)
       # meta[:meta] to keep the API consistent..., gah
       new_state = Workflow::State.new(name, self, meta[:meta])

test/main_test.rb

@@ -92,6 +92,23 @@ class MainTest < Minitest::Test
     assert_equal 'one', c.new.current_state.to_s
   end
 
+  test 'including a child workflow definition for composable workflows' do
+    child = Proc.new do
+      state :two
+    end
+
+    c = Class.new
+    c.class_eval do
+      include Workflow
+      workflow do
+        state :one
+        include child
+        state :three
+      end
+    end
+    assert_equal [:one, :two, :three], c.workflow_spec.states.keys
+  end
+
   # TODO Consider following test case:
   # test 'multiple events with the same name and different arguments lists from different states'
 
@@ -354,4 +371,3 @@ def capture_streams
   end
 
 end
-