Abort animation start if the properties are already being animated

framer/Animation.coffee

@@ -98,11 +98,16 @@ class exports.Animation extends EventEmitter
			@_stateB[k] = v if @_stateA[k] != v

		if _.isEqual(@_stateA, @_stateB)
			console.warn "Nothing to animate"
			return
			console.warn "Animation: nothing to animate, all properties are equal to what it is now"
			return false

		# See if another animation targeting the same layer is animating the same properties

		for runningAnimation in @_target.animations()
			for key in _.keys(runningAnimation._stateA)
				if @_stateA.hasOwnProperty(key)
					console.warn "Animation: property #{key} is already being animated for this 
						layer by another animation, so we bail"
					return false

		if @options.debug
			console.log "Animation.start"
@@ -124,6 +129,8 @@ class exports.Animation extends EventEmitter
		else
			@_start()

		return true

	stop: (emit=true)->
		@options.layer._context._animationList = _.without(
			@options.layer._context._animationList, @)

test/tests/LayerAnimationTest.coffee

@@ -103,6 +103,25 @@ describe "LayerAnimation", ->
				layer.x.should.be.within(10, 40)
				done()

		it "should not start animating the same property", ->

			layer = new Layer()

			animationA = new Animation
				layer: layer
				properties: {x:50}
				curve: "linear"
				time: 0.5

			animationB = new Animation
				layer: layer
				properties: {x:50}
				curve: "linear"
				time: 0.5

			animationA.start().should.equal true
			animationB.start().should.equal false

	describe "Context", ->

		it "should list running animations", ->