Replace existing transition

Fixes #82

CHANGELOG.md

@@ -1,60 +0,0 @@
-## Monarch 2.8.0 [britzl released 2018-06-10]
-NEW: Prevent show/hide operations while busy showing/hiding another screen  
-FIX: Make sure to properly finish active transitions when layout changes
-
-## Monarch 2.7.0 [britzl released 2018-06-04]
-NEW: Added monarch.top([offset]) and monarch.bottom([offset]) to get screen id of top and bottom screens (w. optional offset)  
-NEW: Transition messages now contain `next_screen` or `previous_screen`
-
-## Monarch 2.6.1 [britzl released 2018-06-04]
-FIX: Check if screen has already been preloaded before trying to preload it again (the callback will still be invoked).
-
-## Monarch 2.6.0 [britzl released 2018-06-03]
-NEW: monarch.preload() to load but not show a screen. Useful for content heavy screens that you wish to show without delay.
-
-## Monarch 2.5.0 [britzl released 2018-06-01]
-NEW: Transitions will send a `transition_done` message to the creator of the transition to notify that the transition has finished. The `message` will contain which transition that was finished.
-
-## Monarch 2.4.0 [britzl released 2018-05-26]
-NEW: Screen transitions are remembered so that they can be replayed when the screen layout changes.
-
-## Monarch 2.3.0 [britzl released 2018-03-24]
-CHANGE: The functions in monarch.lua that previously only accepted a hash as screen id now also accepts strings (and does the conversion internally)
-
-## Monarch 2.2.0 [britzl released 2018-03-19]
-NEW: Transitions now handle layout changes (via `layout_changed` message)  
-NEW: Transitions can now be notified of changes in window size using transition.window_resize(width, height)
-
-## Monarch 2.1 [britzl released 2017-12-27]
-NEW: Added Popup on Popup flag that allows a popup to be shown on top of another popup
-
-## Monarch 2.0 [britzl released 2017-12-08]
-BREAKING CHANGE: If you are using custom screen transitions (ie your own transition functions) you need to make a change to the function. The previous function signature was ```(node, to, easing, duration, delay, url)``` where ```url``` was the URL  to where the ```transition_done``` message was supposed to be posted. The new function signature for a transition function is: ```(node, to, easing, duration, delay, cb)``` where ```cb``` is a function that should be invoked when the transition is completed.  
-  
-FIX: Fixed issues related to screen transitions.  
-FIX: Code cleanup to reduce code duplication.  
-FIX: Improved documentation regarding transitions.
-
-## Monarch 1.4 [britzl released 2017-12-06]
-FIX: Several bugfixes for specific corner cases.
-
-## Monarch 1.3 [britzl released 2017-12-01]
-FIX: monarch.back(data, cb) set the data on the previous screen not the new current screen.  
-NEW: monarch.is_top(id)  
-NEW: monarch.get_stack()  
-NEW: monarch.in_stack(id)
-
-## Monarch 1.2 [britzl released 2017-11-28]
-NEW: Message id constants exposed from the Monarch module  
-NEW: Focus lost/gained contains id of next/previous screen
-
-## Monarch 1.1 [britzl released 2017-11-22]
-FIX: Bugfixes for transitions and state under certain circumstances  
-NEW: Added 'reload' option to show() command.
-
-## Monarch 1.0 [britzl released 2017-09-28]
-First public stable release
-
-## Monarch 0.9 [britzl released 2017-09-17]
-
-

README_API.md

@@ -33,6 +33,13 @@ Hide a screen that has been shown using the `no_stack` option. If used on a scre
 * `success` (boolean) - True if the process of hiding the screen was started successfully.
 
 
+## monarch.clear([callback])
+Clear the stack of screens completely. Any visible screen will be hidden by navigating back out from them. This operation will be added to the queue if Monarch is busy.
+
+**PARAMETERS**
+* `callback` (function) - Optional function to call when the stack has been cleared.
+
+
 ## monarch.back([data], [callback])
 Go back to a previous Monarch screen. This operation will be added to the queue if Monarch is busy.
 
@@ -142,6 +149,14 @@ Check if a Monarch screen is visible.
 * `exists` (boolean) - True if the screen is visible.
 
 
+## monarch.set_timestep_below_popup(screen_id, timestep)
+Set the timestep to apply for a screen when below a popup.
+
+**PARAMETERS**
+* `screen_id` (string|hash) - Id of the screen to change timestep setting for
+* `timestep` (number) - Timestep to apply
+
+
 ## monarch.add_listener([url])
 Add a URL that will be notified of navigation events.
 

game.project

@@ -1,7 +1,7 @@
 [project]
 title = Monarch
 version = 0.9
-dependencies = https://github.com/britzl/deftest/archive/2.7.0.zip
+dependencies#0 = https://github.com/britzl/deftest/archive/2.7.0.zip
 
 [bootstrap]
 main_collection = /example/advanced/advanced.collectionc

monarch/monarch.lua

@@ -1,4 +1,5 @@
 local callback_tracker = require "monarch.utils.callback_tracker"
+local async = require "monarch.utils.async"
 
 local M = {}
 
@@ -185,7 +186,7 @@ function M.is_visible(id)
 	assert(id, "You must provide a screen id")
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
-	return screens[id].loaded
+	return screens[id].visible
 end
 
 
@@ -570,6 +571,7 @@ local function show_out(screen, next_screen, wait_for_transition, cb)
 		local current_is_popup = screen.popup
 		if (not next_is_popup and not current_is_popup) or (current_is_popup) then
 			transition(screen, M.TRANSITION.SHOW_OUT, { next_screen = next_screen.id }, wait_for_transition)
+			screen.visible = false
 			unload(screen)
 		elseif next_is_popup then
 			change_timestep(screen)
@@ -590,21 +592,22 @@ local function show_in(screen, previous_screen, reload, add_to_stack, wait_for_t
 			log("show_in() reloading", screen.id)
 			unload(screen, reload)
 		end
+		if add_to_stack then
+			stack[#stack + 1] = screen
+		end
 		local ok, err = load(screen)
 		if not ok then
 			log("show_in()", err)
+			if add_to_stack then
+				stack[#stack] = nil
+			end
 			active_transition_count = active_transition_count - 1
 			notify_transition_listeners(M.SCREEN_TRANSITION_FAILED, { screen = screen.id })
 			return
 		end
-		-- wait until screen has had a chance to render
-		cowait(0)
-		cowait(0)
-		if add_to_stack then
-			stack[#stack + 1] = screen
-		end
 		reset_timestep(screen)
 		transition(screen, M.TRANSITION.SHOW_IN, { previous_screen = previous_screen and previous_screen.id }, wait_for_transition)
+		screen.visible = true
 		acquire_input(screen)
 		focus_gained(screen, previous_screen)
 		active_transition_count = active_transition_count - 1
@@ -626,13 +629,11 @@ local function back_in(screen, previous_screen, wait_for_transition, cb)
 			notify_transition_listeners(M.SCREEN_TRANSITION_FAILED, { screen = screen.id })
 			return
 		end
-		-- wait until screen has had a chance to render
-		cowait(0)
-		cowait(0)
 		reset_timestep(screen)
 		if previous_screen and not previous_screen.popup then
 			transition(screen, M.TRANSITION.BACK_IN, { previous_screen = previous_screen.id }, wait_for_transition)
 		end
+		screen.visible = true
 		acquire_input(screen)
 		focus_gained(screen, previous_screen)
 		active_transition_count = active_transition_count - 1
@@ -653,6 +654,7 @@ local function back_out(screen, next_screen, wait_for_transition, cb)
 			reset_timestep(next_screen)
 		end
 		transition(screen, M.TRANSITION.BACK_OUT, { next_screen = next_screen and next_screen.id }, wait_for_transition)
+		screen.visible = false
 		unload(screen)
 		active_transition_count = active_transition_count - 1
 		notify_transition_listeners(M.SCREEN_TRANSITION_OUT_FINISHED, { screen = screen.id, next_screen = next_screen and next_screen.id })
@@ -743,8 +745,9 @@ function M.show(id, options, data, cb)
 						pop = pop - 1
 					end
 					stack[#stack] = nil
-					show_out(top, screen, WAIT_FOR_TRANSITION, callbacks.track())
-					callbacks.yield_until_done()
+					async(function(await, resume)
+						await(show_out, top, screen, WAIT_FOR_TRANSITION, resume)
+					end)
 					top = stack[#stack]
 				end
 
@@ -783,15 +786,16 @@ function M.show(id, options, data, cb)
 			local same_screen = top and top.id == screen.id
 			if same_screen or (options and options.sequential) then
 				if top then
-					show_out(top, screen, WAIT_FOR_TRANSITION, callbacks.track())
-					callbacks.yield_until_done()
+					async(function(await, resume)
+						await(show_out, top, screen, WAIT_FOR_TRANSITION, resume)
+					end)
 				end
 				show_in(screen, top, options and options.reload, add_to_stack, WAIT_FOR_TRANSITION, callbacks.track())
 			else
 				-- show screen
 				local cb = callbacks.track()
 				show_in(screen, top, options and options.reload, add_to_stack, DO_NOT_WAIT_FOR_TRANSITION, function()
-					if top and not top.popup then
+					if add_to_stack and top and not top.popup then
 						show_out(top, screen, WAIT_FOR_TRANSITION, callbacks.track())
 					end
 					cb()
@@ -825,7 +829,7 @@ end
 
 -- Hide a screen. The screen must either be at the top of the stack or
 -- visible but not added to the stack (through the no_stack option)
--- @param id (string|hash) - Id of the screen to show
+-- @param id (string|hash) - Id of the screen to .hide
 -- @param cb (function) - Optional callback to invoke when the screen is hidden
 -- @return true if successfully hiding, false if busy or for some other reason unable to hide the screen
 function M.hide(id, cb)
@@ -862,6 +866,34 @@ function M.hide(id, cb)
 end
 
 
+
+
+-- Clear stack completely. Any visible screens will be hidden by navigating back out
+-- from them.
+-- @param cb (function) - Optional callback to invoke when the stack has been cleared
+function M.clear(cb)
+	log("clear() queuing action")
+
+	queue_action(function(action_done, action_error)
+		async(function(await, resume)
+			local top = stack[#stack]
+			while top and top.visible do
+				stack[#stack] = nil
+				await(back_out, top, screen, WAIT_FOR_TRANSITION, resume)
+				top = stack[#stack]
+			end
+
+			while stack[#stack] do
+				table.remove(stack)
+			end
+
+			pcallfn(cb)
+			pcallfn(action_done)
+		end)
+	end)
+end
+
+
 -- Go back to the previous screen in the stack.
 -- @param data (*) - Optional data to set for the previous screen
 -- @param cb (function) - Optional callback to invoke when the previous screen is visible again
@@ -870,6 +902,7 @@ function M.back(data, cb)
 
 	queue_action(function(action_done)
 		local callbacks = callback_tracker()
+		local back_cb = callbacks.track()
 		local screen = table.remove(stack)
 		if screen then
 			log("back()", screen.id)
@@ -881,7 +914,7 @@ function M.back(data, cb)
 					if data then
 						top.data = data
 					end
-					back_in(top, screen, WAIT_FOR_TRANSITION, callbacks.track())
+					back_in(top, screen, WAIT_FOR_TRANSITION, back_cb)
 				end)
 			else
 				if top then
@@ -889,10 +922,10 @@ function M.back(data, cb)
 						top.data = data
 					end
 					back_in(top, screen, DO_NOT_WAIT_FOR_TRANSITION, function()
-						back_out(screen, top, WAIT_FOR_TRANSITION, callbacks.track())
+						back_out(screen, top, WAIT_FOR_TRANSITION, back_cb)
 					end)
 				else
-					back_out(screen, top, WAIT_FOR_TRANSITION, callbacks.track())
+					back_out(screen, top, WAIT_FOR_TRANSITION, back_cb)
 				end
 			end
 		end
@@ -1122,6 +1155,19 @@ function M.bottom(offset)
 	return screen and screen.id
 end
 
+
+--- Set the timestep to apply for a screen when below a popup
+-- @param id (string|hash) Id of the screen to change timestep setting for
+-- @param timestep (number) Timestep to apply
+function M.set_timestep_below_popup(id, timestep)
+	assert(id, "You must provide a screen id")
+	assert(timestep, "You must provide a timestep")
+	id = tohash(id)
+	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
+	screens[id].timestep_below_popup = timestep
+end
+
+
 local function url_to_key(url)
 	return (url.socket or hash("")) .. (url.path or hash("")) .. (url.fragment or hash(""))
 end

monarch/transitions/gui.lua

@@ -121,11 +121,15 @@ local function create()
 	local current_transition = nil
 
 	local function create_transition(transition_id, node, fn, easing, duration, delay)
+		assert(transition_id, "You must provide a valid transition id")
+		assert(node, "You must provide a node")
+		assert(fn, "You must provide a transition function")
+
 		local t = transitions[transition_id]
 		-- find if there's already a transition for the node in
 		-- question and if so update it instead of creating a new
 		-- transition
-		for _,transition in ipairs(t) do
+		for _,transition in ipairs(t.transitions) do
 			if transition.node == node then
 				transition.fn = fn
 				transition.easing = easing

monarch/utils/async.lua

@@ -0,0 +1,47 @@
+local M = {}
+
+local NOT_STARTED = "not_started"
+local YIELDED = "yielded"
+local RESUMED = "resumed"
+local RUNNING = "running"
+
+function M.async(fn)
+	local co = coroutine.running()
+	
+	local state = NOT_STARTED
+
+	local function await(fn, ...)
+		state = RUNNING
+		fn(...)
+		if state ~= RUNNING then
+			return
+		end
+		state = YIELDED
+		local r = { coroutine.yield() }
+		return unpack(r)
+	end
+
+	local function resume(...)
+		if state ~= RUNNING then
+			state = RUNNING
+			local ok, err = coroutine.resume(co, ...)
+			if not ok then
+				print(err)
+				print(debug.traceback())
+			end
+		end
+	end
+
+	if co then
+		return fn(await, resume)
+	else
+		co = coroutine.create(fn)
+		return resume(await, resume)
+	end
+end
+
+return setmetatable(M, {
+	__call = function(t, ...)
+		return M.async(...)
+	end
+})

monarch/utils/callback_tracker.lua

@@ -6,13 +6,18 @@ function M.create()
 
 	local callback = nil
 	local callback_count = 0
+	local all_callbacks_done = false
 
 	local function is_done()
 		return callback_count == 0
 	end
 
 	local function invoke_if_done()
+		if all_callbacks_done then
+			print("Warning: The same callback will be invoked twice from the callback tracker!", id or "")
+		end
 		if callback_count == 0 and callback then
+			all_callbacks_done = true
 			local ok, err = pcall(callback)
 			if not ok then print(err) end
 		end
@@ -41,20 +46,6 @@ function M.create()
 		invoke_if_done()
 	end
 
-	function instance.yield_until_done()
-		local co = coroutine.running()
-		callback = function()
-			local ok, err = coroutine.resume(co)
-			if not ok then
-				print(err)
-			end
-		end
-		invoke_if_done()
-		if not is_done() then
-			coroutine.yield()
-		end
-	end
-
 	return instance
 end
 

test/test_monarch.lua

@@ -39,7 +39,7 @@ return function()
 
 	local screens_instances = {}
 
-	local function is_shown(screen_id)
+	local function is_visible(screen_id)
 		return monarch.is_visible(screen_id)
 	end
 
@@ -65,9 +65,6 @@ return function()
 	local function wait_until_visible(screen_id)
 		return wait_timeout(is_visible, screen_id)
 	end
-	local function wait_until_shown(screen_id)
-		return wait_timeout(is_shown, screen_id)
-	end
 	local function wait_until_hidden(screen_id)
 		return wait_timeout(is_hidden, screen_id)
 	end
@@ -145,23 +142,23 @@ return function()
 			assert(not monarch.is_visible(SCREEN1))
 			monarch.show(SCREEN1)
 			assert(wait_until_stack({ SCREEN1 }))
-			assert(monarch.is_visible(SCREEN1))
+			assert(wait_until_visible(SCREEN1))
 			
 			monarch.show(SCREEN2)
 			assert(wait_until_stack({ SCREEN1, SCREEN2 }))
-			assert(not monarch.is_visible(SCREEN1))
-			assert(monarch.is_visible(SCREEN2))
+			assert(wait_until_hidden(SCREEN1))
+			assert(wait_until_visible(SCREEN2))
 			
 			monarch.show(POPUP1)
 			assert(wait_until_stack({ SCREEN1, SCREEN2, POPUP1 }))
-			assert(not monarch.is_visible(SCREEN1))
-			assert(monarch.is_visible(SCREEN2))
-			assert(monarch.is_visible(POPUP1))
+			assert(wait_until_hidden(SCREEN1))
+			assert(wait_until_visible(SCREEN2))
+			assert(wait_until_visible(POPUP1))
 		end)
 
 		it("should be able to show a screen without adding it to the stack", function()
 			monarch.show(BACKGROUND, { no_stack = true })
-			assert(wait_until_shown(BACKGROUND), "Background was never shown")
+			assert(wait_until_visible(BACKGROUND), "Background was never shown")
 			assert(wait_until_stack({ }))
 
 			monarch.show(SCREEN1)
@@ -175,7 +172,7 @@ return function()
 			
 			monarch.show(BACKGROUND, { no_stack = true })
 			assert(wait_until_not_busy())
-			assert(wait_until_shown(BACKGROUND))
+			assert(wait_until_visible(BACKGROUND))
 			assert(wait_until_stack({ SCREEN1 }))
 			
 			monarch.show(SCREEN2)
@@ -184,13 +181,13 @@ return function()
 
 			monarch.back()
 			assert(wait_until_not_busy())
-			assert(wait_until_shown(SCREEN1))
+			assert(wait_until_visible(SCREEN1))
 			assert(wait_until_stack({ SCREEN1 }))
 		end)
 		
 		it("should be able to hide a screen not added to the stack", function()
 			monarch.show(BACKGROUND, { no_stack = true })
-			assert(wait_until_shown(BACKGROUND), "Background was never shown")
+			assert(wait_until_visible(BACKGROUND), "Background was never shown")
 			assert_stack({ })
 
 			monarch.hide(BACKGROUND)
@@ -213,18 +210,18 @@ return function()
 		it("should be able to pass data to a screen when showing it or going back to it", function()
 			local data1 = { foo = "bar" }
 			monarch.show(SCREEN1, nil, data1)
-			assert(wait_until_shown(SCREEN1), "Screen1 was never shown")
+			assert(wait_until_visible(SCREEN1), "Screen1 was never shown")
 
 			local data2 = { boo = "car" }
 			monarch.show(SCREEN2, nil, data2)
-			assert(wait_until_shown(SCREEN2), "Screen2 was never shown")
+			assert(wait_until_visible(SCREEN2), "Screen2 was never shown")
 			
 			assert(monarch.data(SCREEN1) == data1, "Expected data on screen1 doesn't match actual data")
 			assert(monarch.data(SCREEN2) == data2, "Expected data on screen2 doesn't match actual data")
 
 			local data_back = { going = "back" }
 			monarch.back(data_back)
-			assert(wait_until_shown(SCREEN1))
+			assert(wait_until_visible(SCREEN1))
 
 			assert(monarch.data(SCREEN1) == data_back, "Expected data on screen1 doesn't match actual data")
 		end)
@@ -368,7 +365,7 @@ return function()
 		it("should be busy while transition is running", function()
 			monarch.show(TRANSITION1)
 			assert(monarch.is_busy())
-			assert(wait_until_shown(TRANSITION1), "Transition1 was never shown")
+			assert(wait_until_visible(TRANSITION1), "Transition1 was never shown")
 			assert(wait_until_not_busy())
 		end)
 
@@ -386,7 +383,7 @@ return function()
 			-- previously a call to preload() while also showing a screen would
 			-- lock up monarch. See issue #32
 			monarch.preload(TRANSITION1)
-			assert(wait_until_shown(TRANSITION1), "Transition1 was never shown")
+			assert(wait_until_visible(TRANSITION1), "Transition1 was never shown")
 		end)
 		
 		it("should be able to notify listeners of navigation events", function()
@@ -438,12 +435,12 @@ return function()
 		
 		it("should be able to show a screen even while it is preloading", function()
 			monarch.show(SCREEN_PRELOAD, nil, { count = 1 })
-			assert(wait_until_shown(SCREEN_PRELOAD), "Screen_preload was never shown")
+			assert(wait_until_visible(SCREEN_PRELOAD), "Screen_preload was never shown")
 		end)
 		
 		it("should be able to preload a screen and always keep it loaded", function()
 			monarch.show(SCREEN_PRELOAD)
-			assert(wait_until_shown(SCREEN_PRELOAD), "Screen_preload was never shown")
+			assert(wait_until_visible(SCREEN_PRELOAD), "Screen_preload was never shown")
 			monarch.back()
 			assert(wait_until_hidden(SCREEN_PRELOAD), "Screen_preload was never hidden")
 			assert(monarch.is_preloaded(SCREEN_PRELOAD))
@@ -451,12 +448,12 @@ return function()
 
 		it("should be able to reload a preloaded screen", function()
 			monarch.show(SCREEN_PRELOAD, nil, { count = 1 })
-			assert(wait_until_shown(SCREEN_PRELOAD), "Screen_preload was never shown")
+			assert(wait_until_visible(SCREEN_PRELOAD), "Screen_preload was never shown")
 			-- first time the screen gets loaded it will increment the count
 			assert(monarch.data(SCREEN_PRELOAD).count == 2)
 
 			monarch.show(SCREEN_PRELOAD, { clear = true, reload = true }, { count = 1 })
-			assert(wait_until_shown(SCREEN_PRELOAD), "Screen_preload was never shown")
+			assert(wait_until_visible(SCREEN_PRELOAD), "Screen_preload was never shown")
 			-- second time the screen gets shown it will be reloaded and increment the count
 			assert(monarch.data(SCREEN_PRELOAD).count == 2)
 		end)
@@ -470,9 +467,11 @@ return function()
 			assert(wait_until_stack({ SCREEN1 }))
 			monarch.show(FOCUS1)
 			assert(wait_until_stack({ SCREEN1, FOCUS1 }))
+			assert(wait_until_visible(FOCUS1))
 			assert(_G.focus1_gained)
 			monarch.show(SCREEN1)
 			assert(wait_until_stack({ SCREEN1, FOCUS1, SCREEN1 }))
+			assert(wait_until_hidden(FOCUS1))
 			assert(_G.focus1_lost)
 		end)
 
@@ -483,14 +482,14 @@ return function()
 
 			-- proxy screen
 			monarch.show(SCREEN1)
-			wait_until_shown(SCREEN1)
+			wait_until_visible(SCREEN1)
 			assert(monarch.post(SCREEN1, "foobar"), "Expected monarch.post() to return true")
 			cowait(0.1)
 			assert(_G.screen1_foobar, "Screen1 never received a message")
 
 			-- factory screen
 			monarch.show(SCREEN2)
-			wait_until_shown(SCREEN2)
+			wait_until_visible(SCREEN2)
 			assert(monarch.post(SCREEN2, "foobar"), "Expected monarch.post() to return true")
 			cowait(0.1)
 			assert(_G.screen2_foobar, "Screen2 never received a message")
@@ -503,7 +502,7 @@ return function()
 
 			-- proxy screen
 			monarch.show(SCREEN1)
-			wait_until_shown(SCREEN1)
+			wait_until_visible(SCREEN1)
 			assert(monarch.post(SCREEN1, "foobar", { foo = "bar" }), "Expected monarch.post() to return true")
 			cowait(0.1)
 			assert(_G.screen1_foobar, "Screen1 never received a message")
@@ -511,7 +510,7 @@ return function()
 			
 			-- factory screen
 			monarch.show(SCREEN2)
-			wait_until_shown(SCREEN2)
+			wait_until_visible(SCREEN2)
 			assert(monarch.post(SCREEN2, "foobar", { foo = "bar" }), "Expected monarch.post() to return true")
 			cowait(0.1)
 			assert(_G.screen2_foobar, "Screen2 never received a message")
@@ -525,6 +524,7 @@ return function()
 			monarch.show(SCREEN1)
 			monarch.show(SCREEN2)
 			assert(wait_until_stack({ SCREEN1, SCREEN2 }))
+			assert(wait_until_hidden(SCREEN1))
 			local ok, err = monarch.post(SCREEN1, "foobar")
 			assert(not ok and err, "Expected monarch.post() to return false plus an error message")
 			cowait(0.1)
@@ -534,7 +534,7 @@ return function()
 
 		it("should not be able to post messages to proxy screens without a receiver url", function()
 			monarch.show(POPUP1)
-			wait_until_shown(POPUP1)
+			wait_until_visible(POPUP1)
 			local ok, err = monarch.post(POPUP1, "foobar")
 			assert(not ok and err, "Expected monarch.post() to return false plus an error message")
 		end)

test/test_transitions.lua

@@ -8,6 +8,12 @@ local easing = require "monarch.transitions.easings"
 
 return function()
 
+local function wait_timeout(fn, ...)
+	local args = { ... }
+	cowait(function() return fn(unpack(args)) end, 5)
+	return fn(...)
+end
+
 describe("transitions", function()
 	before(function()
 		mock_msg.mock()
@@ -22,6 +28,28 @@ describe("transitions", function()
 	end)
 
 
+	it("should replace an existing transition with a new one", function()
+		local one = false
+		function dummy_transition1(node, to, easing, duration, delay, cb)
+			one = true
+		end
+		local two = false
+		function dummy_transition2(node, to, easing, duration, delay, cb)
+			two = true
+		end
+		
+		local node = gui.new_box_node(vmath.vector3(), vmath.vector3(100, 100, 0))
+		local duration = 2
+		local t = transitions.create(node)
+		t.show_in(dummy_transition1, easing.OUT, duration, delay or 0)
+		t.show_in(dummy_transition2, easing.OUT, duration, delay or 0)
+		t.handle(monarch.TRANSITION.SHOW_IN)
+		
+		wait_timeout(function() return one or two end)
+		assert(two)
+		assert(not one)
+	end)
+
 	it("should replay and immediately finish on layout change", function()
 		function dummy_transition(node, to, easing, duration, delay, cb)
 			print("dummy transition")