Test programs

function turtle.forwards(numForw)
    for i = 1, numForw do
        turtle.forward()
    end
end

function turtle.upwards(numUpw)
    for i = 1, numUpw do
        turtle.up()
    end
end

function turtle.downwards(numDownw)
    for i = 1, numDownw do
        turtle.down()
    end
end

function turtle.turns180()
    for i = 1, 2 do
        turtle.turnRight()
    end
end

function inventoryCheck()
    for i = 1, 16 do
        if turtle.getItemCount(i) ~= 0 then
            return false
        end
    end
    return true
end

local startX, startY, startZ = 0, 0, 0
local currX, currY, currZ = startX, startY, startZ
local currDir = "north"

function updatePosition(newX, newY, newZ)
    currX, currY, currZ = newX, newY, newZ
end

function updateDirection(newDir)
    currDir = newDir
end

function turnTo(dir)
    if dir == "north" then
        if currDir == "east" then
            turtle.turnLeft()
        elseif currDir == "south" then
            turtle.turn180()
        elseif currDir == "west" then
            turtle.turnRight()
        end
    elseif dir == "east" then
        if currDir == "north" then
            turtle.turnRight()
        elseif currDir == "south" then
            turtle.turnLeft()
        elseif currDir == "west" then
            turtle.turn180()
        end
    elseif dir == "south" then
        if currDir == "north" then
            turtle.turn180()
        elseif currDir == "east" then
            turtle.turnRight()
        elseif currDir == "west" then
            turtle.turnLeft()
        end
   elseif dir == "west" then
        if currDir == "north" then
            turtle.turnLeft()
        elseif currDir == "east" then
            turtle.turn180()
        elseif currDir == "south" then
            turtle.turnRight()
        end
   end
   updateDirection(dir)
end

function returnToStart()
    while currX ~= startX or currY ~= startY or currZ ~= startZ do
        if currY > startY then
            turtle.down()
            updatePosition(currX, currY - 1, currZ)
        elseif currY < startY then
            turtle.up()
            updatePosition(currX, currY + 1, currZ)
        elseif currZ > startZ then
            turnTo("north")
            turtle.forward()
            updatePosition(currX, currY, currZ - 1)
        elseif currZ < startZ then
            turnTo("south")
            turtle.forward()
            updatePosition(currX, currY, currZ + 1)
        elseif currX > startX then
            turnTo("west")
            turtle.forward()
            updatePosition(currX - 1, currY, currZ)
        elseif currX < startX then
            turnTo("east")
            turtle.forward()
            updatePosition(currX + 1, currY, currZ)
        end
    end
end


function inventoryTest()
    while true do
        if inventoryCheck() then
            returnToStart()
            turtle.turns180()
            for i = 1, 16 do
                turtle.select(i)
                if turtle.getItemCount() ~= 0 then
                    turtle.drop()
                end
            end
            turtle.turns180()
        else
            sleep(0.1)
        end
    end
end

turtle.forwards(5)
turtle.turnLeft()
turtle.forwards(2)
inventoryTest()