Added deprecated event support on states

Signed-off-by: Niels van Hoorn <nvh@nvh.io>

framer/LayerStates.coffee

@@ -77,6 +77,9 @@ class exports.LayerStates
 				for name, state of layer.states
 					keys = _.union(keys, _.keys(state))
 				keys
+		deprecatedProperty @, "on", "layer.on", stateMachine, (layer) ->
+			(name, handler) ->
+				layer.on(name, handler)
 
 	@filterStateProperties: (properties) ->
 

test/tests/LayerStatesTest.coffee

@@ -507,3 +507,34 @@ describe "LayerStates", ->
 			layerB.states.next(instant: true)
 			assert.equal layerB.y, 300
 			assert.equal layerB.x, 400
+
+		describe "Events", ->
+
+			beforeEach ->
+				@layer = new Layer()
+				@layer.states.add("a", {x:100, y:100})
+				@layer.states.add("b", {x:200, y:200})
+
+			it "should emit willSwitch when switching", (done) ->
+
+				test = (previous, current, states) =>
+					previous.should.equal 'initial'
+					current.should.equal 'a'
+					@layer.states.state.should.equal 'initial'
+					done()
+
+				@layer.states.on 'willSwitch', test
+				@layer.states.switchInstant 'a'
+
+			it "should emit didSwitch when switching", (done) ->
+
+				test = (previous, current, states) =>
+					previous.should.equal 'initial'
+					current.should.equal 'a'
+					@layer.states.state.should.equal 'a'
+					done()
+
+				@layer.states.on 'didSwitch', test
+				@layer.states.switchInstant 'a'
+
+