Added callback tracker tests

test/test_callback_tracker.lua

@@ -0,0 +1,69 @@
+local unload = require "deftest.util.unload"
+local cowat = require "test.cowait"
+local callback_tracker = require "monarch.utils.callback_tracker"
+
+return function()
+
+	describe("callback tracker", function()
+		before(function()
+			callback_tracker = require "monarch.utils.callback_tracker"
+		end)
+
+		after(function()
+			unload.unload("monarch%..*")
+		end)
+
+
+		it("should be able to tell when all callbacks are done", function()
+			local tracker = callback_tracker.create()
+			local t1 = tracker.track()
+			local t2 = tracker.track()
+
+			local done = false
+			tracker.when_done(function() done = true end)
+			
+			assert(not done, "It should not be done yet - No callback has completed")
+			t1()
+			assert(not done, "It should not be done yet - Only one callback has completed")
+			t2()
+			assert(done, "It should be done now - All callbacks have completed")
+		end)
+
+		it("should indicate if a tracked callback has been invoked more than once", function()
+			local tracker = callback_tracker.create()
+			local t = tracker.track()
+			local ok, err = t()
+			assert(ok == true and err == nil, "It should return true when successful")
+			ok, err = t()
+			assert(ok == false and err, "It should return false and a message when invoked multiple times")
+		end)
+
+		it("should not be possible to track the same callback more than one time", function()
+			local tracker = callback_tracker.create()
+			local t1 = tracker.track()
+			local t2 = tracker.track()
+
+			local done = false
+			tracker.when_done(function() done = true end)
+
+			assert(not done, "It should not be done yet - No callback has completed")
+			t1()
+			t1()
+			assert(not done, "It should not be done yet - Even if one callback has been invoked twice")
+			t2()
+			assert(done, "It should be done now - All callbacks have completed")
+		end)
+
+		it("should handle when callbacks are done before calling when_done()", function()
+			local tracker = callback_tracker.create()
+			local t1 = tracker.track()
+			local t2 = tracker.track()
+			t1()
+			t2()
+
+			local done = false
+			tracker.when_done(function() done = true end)
+			assert(done, "It should be done now - All callbacks have completed")
+		end)
+	end)
+end