diff --git a/technic/spec/hv_network_spec.lua b/technic/spec/hv_network_spec.lua
index f4ceb7f7..2c3b2a2e 100644
--- a/technic/spec/hv_network_spec.lua
+++ b/technic/spec/hv_network_spec.lua
@@ -52,7 +52,7 @@ describe("HV machine network", function()
 		local meta = minetest.get_meta(pos)
 		local inv = meta:get_inventory()
 		if not inv:room_for_item(listname or "src", itemstack) then
-			inv:set_stack(listname or "src", 1, ItemStack())
+			inv:set_stack(listname or "src", 1, ItemStack(nil))
 		end
 		inv:add_item(listname or "src", itemstack)
 	end
diff --git a/technic/spec/lv_network_spec.lua b/technic/spec/lv_network_spec.lua
index fbe74b5d..219801ab 100644
--- a/technic/spec/lv_network_spec.lua
+++ b/technic/spec/lv_network_spec.lua
@@ -78,7 +78,7 @@ describe("LV machine network", function()
 		local meta = minetest.get_meta(pos)
 		local inv = meta:get_inventory()
 		if not inv:room_for_item(listname or "src", itemstack) then
-			inv:set_stack(listname or "src", 1, ItemStack())
+			inv:set_stack(listname or "src", 1, ItemStack(nil))
 		end
 		inv:add_item(listname or "src", itemstack)
 	end
diff --git a/technic/spec/tools_compatibility_spec.lua b/technic/spec/tools_compatibility_spec.lua
index 07bc4bfb..10f2b6b6 100644
--- a/technic/spec/tools_compatibility_spec.lua
+++ b/technic/spec/tools_compatibility_spec.lua
@@ -59,8 +59,8 @@ describe("Technic power tool compatibility", function()
 			end)
 
 			before_each(function()
-				set_charge_stack(ItemStack())
-				set_discharge_stack(ItemStack())
+				set_charge_stack(ItemStack(nil))
+				set_discharge_stack(ItemStack(nil))
 			end)
 
 			it("is registered", function()
diff --git a/technic/spec/tools_spec.lua b/technic/spec/tools_spec.lua
index 7bcd6370..dbeb89a3 100644
--- a/technic/spec/tools_spec.lua
+++ b/technic/spec/tools_spec.lua
@@ -56,8 +56,8 @@ describe("Technic power tool", function()
 	describe("API", function()
 
 		setup(function()
-			set_charge_stack(ItemStack())
-			set_discharge_stack(ItemStack())
+			set_charge_stack(ItemStack(nil))
+			set_discharge_stack(ItemStack(nil))
 			mineunit:set_current_modname("mymod")
 			mineunit:execute_on_joinplayer(player)
 		end)
@@ -149,8 +149,8 @@ describe("Technic power tool", function()
 		end
 
 		setup(function()
-			set_charge_stack(ItemStack())
-			set_discharge_stack(ItemStack())
+			set_charge_stack(ItemStack(nil))
+			set_discharge_stack(ItemStack(nil))
 			mineunit:set_current_modname("mymod")
 			register_test_tool("t1_1", 1, 1)
 			register_test_tool("t1_2", 1, 2)
@@ -263,8 +263,8 @@ describe("Technic power tool", function()
 		local itemdef = minetest.registered_items[itemname]
 
 		setup(function()
-			set_charge_stack(ItemStack())
-			set_discharge_stack(ItemStack())
+			set_charge_stack(ItemStack(nil))
+			set_discharge_stack(ItemStack(nil))
 			mineunit:execute_on_joinplayer(player)
 		end)
 
@@ -308,8 +308,8 @@ describe("Technic power tool", function()
 		local itemdef = minetest.registered_items[itemname]
 
 		setup(function()
-			set_charge_stack(ItemStack())
-			set_discharge_stack(ItemStack())
+			set_charge_stack(ItemStack(nil))
+			set_discharge_stack(ItemStack(nil))
 			mineunit:execute_on_joinplayer(player)
 			player:get_inventory():set_stack("main", 1, itemname)
 		end)
@@ -401,8 +401,8 @@ describe("Technic power tool", function()
 				-- Some wood for chainsaw
 				{{{x=-10,y=0,z=-10},{x=10,y=10,z=10}}, "default:wood"},
 			})
-			set_charge_stack(ItemStack())
-			set_discharge_stack(ItemStack())
+			set_charge_stack(ItemStack(nil))
+			set_discharge_stack(ItemStack(nil))
 			mineunit:execute_on_joinplayer(player)
 			set_player_stack(itemname)
 		end)
diff --git a/technic_cnc/spec/api_spec.lua b/technic_cnc/spec/api_spec.lua
index c99f70c9..7b78f2a8 100644
--- a/technic_cnc/spec/api_spec.lua
+++ b/technic_cnc/spec/api_spec.lua
@@ -64,7 +64,7 @@ describe("CNC API", function()
 			local meta = minetest.get_meta(pos)
 			local inventory = meta:get_inventory()
 			inventory:set_stack("src", 1, "default:stone 42")
-			inventory:set_stack("dst", 1, ItemStack())
+			inventory:set_stack("dst", 1, ItemStack(nil))
 			local materialstack = inventory:get_stack("src", 1)
 
 			-- Test CNC cutting process
@@ -82,7 +82,7 @@ describe("CNC API", function()
 			local meta = minetest.get_meta(pos)
 			local inventory = meta:get_inventory()
 			inventory:set_stack("src", 1, "default:badstone 42")
-			inventory:set_stack("dst", 1, ItemStack())
+			inventory:set_stack("dst", 1, ItemStack(nil))
 			local materialstack = inventory:get_stack("src", 1)
 
 			-- Test CNC cutting process
diff --git a/technic_cnc/spec/technic_cnc_spec.lua b/technic_cnc/spec/technic_cnc_spec.lua
index ef876cd9..a580415d 100644
--- a/technic_cnc/spec/technic_cnc_spec.lua
+++ b/technic_cnc/spec/technic_cnc_spec.lua
@@ -32,7 +32,7 @@ describe("Technic CNC", function()
 		local meta = minetest.get_meta(pos)
 		local inv = meta:get_inventory()
 		if not inv:room_for_item(listname or "src", itemstack) then
-			inv:set_stack(listname or "src", 1, ItemStack())
+			inv:set_stack(listname or "src", 1, ItemStack(nil))
 		end
 		inv:add_item(listname or "src", itemstack)
 	end
@@ -48,7 +48,7 @@ describe("Technic CNC", function()
 		local meta = minetest.get_meta(pos)
 		local inv = meta:get_inventory()
 		for index=1, inv:get_size(listname or "dst") do
-			inv:set_stack(listname or "dst", index, ItemStack())
+			inv:set_stack(listname or "dst", index, ItemStack(nil))
         end
 	end