Add Lua unit tests to builtin using busted (#9184)

builtin/common/tests/serialize_spec.lua

@@ -0,0 +1,28 @@
+_G.core = {}
+
+_G.setfenv = function() end
+
+dofile("builtin/common/serialize.lua")
+
+describe("serialize", function()
+	it("works", function()
+		local test_in = {cat={sound="nyan", speed=400}, dog={sound="woof"}}
+		local test_out = core.deserialize(core.serialize(test_in))
+
+		assert.same(test_in, test_out)
+	end)
+
+	it("handles characters", function()
+		local test_in = {escape_chars="\n\r\t\v\\\"\'", non_european="θשׁ٩∂"}
+		local test_out = core.deserialize(core.serialize(test_in))
+		assert.same(test_in, test_out)
+	end)
+
+	it("handles recursive structures", function()
+		local test_in = { hello = "world" }
+		test_in.foo = test_in
+
+		local test_out = core.deserialize(core.serialize(test_in))
+		assert.same(test_in, test_out)
+	end)
+end)