Add graph label option to transitions

README.md

@@ -797,6 +797,24 @@ class Vehicle
 end
 ```
 
+#### Transition labels
+
+If you would prefer a custom label on a graphviz generated graph, specify
+the `:graph_label` option on the transition statement.
+
+For example:
+
+```ruby
+
+class Vehicle
+ state_machine :initial => :parked do
+
+ state :parked do
+ transition :to => :idling, :on => [:ignite, :shift_up], :if => :seatbelt_on?, :graph_label => "Seatbelt is ON"
+ end
+end
+```
+
 #### Transition context
 
 Some flexibility is provided around the context in which transitions can be

lib/state_machine/branch.rb

@@ -29,12 +29,16 @@ class Branch
  # * +from+ / +except_from+
  # * +to+ / +except_to+
  attr_reader :known_states
-
+
+ # An optional, custom, label to add to the graph when drawing the branch.
+ attr_reader :graph_label
+
  # Creates a new branch
  def initialize(options = {}) #:nodoc:
  # Build conditionals
  @if_condition = options.delete(:if)
  @unless_condition = options.delete(:unless)
+ @graph_label = options.delete(:graph_label)
 
  # Build event requirement
  @event_requirement = build_matcher(options, :on, :except_on)

lib/state_machine/event.rb

@@ -194,7 +194,7 @@ def reset
  @branches = []
  @known_states = []
  end
-  
+
  # Draws a representation of this event on the given graph. This will
  # create 1 or more edges on the graph for each branch (i.e. transition)
  # configured.
@@ -205,12 +205,18 @@ def reset
  def draw(graph, options = {})
  valid_states = machine.states.by_priority.map {|state| state.name}
  branches.each do |branch|
- branch.draw(graph, options[:human_name] ? human_name : name, valid_states)
+ branch.draw(graph, graph_label(branch, options), valid_states)
  end
 
  true
  end
 
+ def graph_label(branch, options = {})
+ graph_label_name = (options[:human_name] ? human_name : name).to_s
+
+ branch.graph_label ? branch.graph_label : graph_label_name
+ end
+
  # Generates a nicely formatted description of this event's contents.
  # 
  # For example,

lib/state_machine/graph.rb

@@ -86,7 +86,7 @@ def v0_api?
 
  # The ruby-graphviz version data
  def version
- Constants::RGV_VERSION.split('.')
+ GraphViz::Constants::RGV_VERSION.split('.')
  end
  end
 end

state_machine.gemspec

@@ -17,6 +17,8 @@ Gem::Specification.new do |s|
  s.extra_rdoc_files = %w(README.md CHANGELOG.md LICENSE)
 
  s.add_development_dependency("rake")
+ s.add_development_dependency("test-unit")
  s.add_development_dependency("simplecov")
+ s.add_development_dependency("ruby-graphviz")
  s.add_development_dependency("appraisal", "~> 0.5.0")
 end

test/unit/event_test.rb

@@ -1170,6 +1170,28 @@ def test_should_use_event_name_for_edge_label
  end
  end
 
+ class EventDrawingWithCustomBranchLabelTest < Test::Unit::TestCase
+ def setup
+ states = [:parked, :idling]
+
+ @machine = StateMachine::Machine.new(Class.new, :initial => :parked)
+ @machine.other_states(*states)
+
+ graph = StateMachine::Graph.new('test')
+ states.each {|state| graph.add_nodes(state.to_s)}
+
+ @machine.events << @event = StateMachine::Event.new(@machine , :park, :human_name => 'Park')
+ @event.transition :parked => :idling, :graph_label => "extra graph label"
+
+ @event.draw(graph, :human_name => true)
+ @edge = graph.get_edge_at_index(0)
+ end
+
+ def test_should_use_event_human_name_for_edge_label
+ assert_equal 'extra graph label', @edge['label'].to_s.gsub('"', '')
+ end
+ end
+
  class EventDrawingWithHumanNameTest < Test::Unit::TestCase
  def setup
  states = [:parked, :idling]

test/unit/machine_test.rb

@@ -3261,7 +3261,7 @@ def test_should_allow_orientation_to_be_portrait
  assert_equal 'TB', graph['rankdir'].to_s.gsub('"', '')
  end
 
- if Constants::RGV_VERSION != '0.9.0'
+ if GraphViz::Constants::RGV_VERSION != '0.9.0'
  def test_should_allow_human_names_to_be_displayed
  @machine.event :ignite, :human_name => 'Ignite'
  @machine.state :parked, :human_name => 'Parked'