Add automated tests for some mods (#605)

Depends on mineunit from https://github.com/S-S-X/mineunit

mesecons, mesecons_mvps, mesecons_fpga, and mesecons_luacontroller are now tested.

.test_fixtures/mesecons_fpga.lua

@@ -0,0 +1,59 @@
+mineunit("player")
+
+fixture("mesecons")
+fixture("mesecons_gamecompat")
+
+local registered_on_player_receive_fields = {}
+local old_register_on_player_receive_fields = minetest.register_on_player_receive_fields
+function minetest.register_on_player_receive_fields(func)
+	old_register_on_player_receive_fields(func)
+	table.insert(registered_on_player_receive_fields, func)
+end
+
+mineunit:set_current_modname("mesecons_fpga")
+mineunit:set_modpath("mesecons_fpga", "../mesecons_fpga")
+sourcefile("../mesecons_fpga/init")
+
+local fpga_user = Player("mesecons_fpga_user")
+
+function mesecon._test_program_fpga(pos, program)
+	local node = minetest.get_node(pos)
+	assert.equal("mesecons_fpga:fpga", node.name:sub(1, 18))
+
+	local fields = {program = true}
+	for i, instr in ipairs(program) do
+		-- Translate the instruction into formspec fields.
+		local op1, act, op2, dst
+		if #instr == 3 then
+			act, op2, dst = unpack(instr)
+		else
+			assert.equal(4, #instr)
+			op1, act, op2, dst = unpack(instr)
+		end
+		fields[i .. "op1"] = op1
+		fields[i .. "act"] = (" "):rep(4 - #act) .. act
+		fields[i .. "op2"] = op2
+		fields[i .. "dst"] = dst
+	end
+
+	minetest.registered_nodes[node.name].on_rightclick(pos, node, fpga_user)
+
+	for _, func in ipairs(registered_on_player_receive_fields) do
+		if func(fpga_user, "mesecons:fpga", fields) then
+			break
+		end
+	end
+end
+
+function mesecon._test_copy_fpga_program(pos)
+	fpga_user:get_inventory():set_stack("main", 1, "mesecons_fpga:programmer")
+	local pt = {type = "node", under = vector.new(pos), above = vector.offset(pos, 0, 1, 0)}
+	fpga_user:do_place(pt)
+	return fpga_user:get_wielded_item()
+end
+
+function mesecon._test_paste_fpga_program(pos, tool)
+	fpga_user:get_inventory():set_stack("main", 1, tool)
+	local pt = {type = "node", under = vector.new(pos), above = vector.offset(pos, 0, 1, 0)}
+	fpga_user:do_use(pt)
+end