Unit test for preserve_metadata

includeme.lua

if run_unit_tests then
	local test_item_name =
			minetest:get_current_modname()..":preserve_metadata_test_node"
	minetest.register_node(test_item_name, {
		description="test",
		groups={cracky=3, attached_node=1},
		preserve_metadata = function(pos, node, oldmeta, drops)
			drops[1]:get_meta():set_string("test", "metadata_target_string")
		end,
	})
	local delay_func = function()
		local test_parameters = {
			itemname = test_item_name,
			min_pos = { x=30900, y=-30903, z=30900 },
			max_pos = { x=30902, y=-30900, z=30902 },
			testnode_pos = { x=30901, y=-30901, z=30901 },
			sand_pos = { x=30901, y=-30902, z=30901 },
		}
		local test_func = function(bpos, action, calls_remaining, p)
			local key, obj, x, y, z
			for x = p.min_pos.x, p.max_pos.x do
				for y = p.min_pos.y, p.max_pos.y do
					for z = p.min_pos.z, p.max_pos.z do
						minetest.set_node({x=x, y=y, z=z}, { name="default:stone", })
					end
				end
			end
			minetest.set_node(p.sand_pos, { name = "default:sand", })
			minetest.set_node(p.testnode_pos, { name=p.itemname })
			-- Clean out old objects first.
			for key, obj in pairs(minetest.get_objects_inside_radius(
					p.sand_pos, 3)) do
				local lua_entity = obj:get_luaentity()
				if not obj:is_player() and
						lua_entity and lua_entity.name == "__builtin:item" then
					obj:remove()
				end
			end
			minetest.dig_node(p.sand_pos)		-- Detach the node above.
			for key, obj in pairs(minetest.get_objects_inside_radius(
					p.sand_pos, 3)) do
				local lua_entity = obj:get_luaentity()
				if not obj:is_player() and
						lua_entity and lua_entity.name == "__builtin:item" then
					if string.find(lua_entity.itemstring,
							"metadata_target_string") then
						minetest.log("Unit test for preserve_metadata:  PASS.")
					else
						minetest.log("Unit test for preserve_metadata:  FAIL.")
					end
					obj:remove()
				end
			end
			-- Do a rough clean up job.
			minetest.set_node(p.sand_pos, { name="default:stone" })
			minetest.set_node(p.testnode_pos, { name="default:stone" })
		end
		minetest.emerge_area(test_parameters.min_pos, test_parameters.max_pos,
				test_func, test_parameters)
	end
	minetest.after(1, delay_func)
end