Add Test in Segmentation Databunch Help!

I am using fastai for image segmentation task I have the following snippet that works perfectly fine

src = (SegmentationItemList.from_folder(path_img)
       # Load in x data from folder
       .split_by_rand_pct(0.2, seed=13)
       # Split data into training and validation set 
       .label_from_func(get_y_fn, classes=codes)
       # Label data using the get_y_fn function
data = (src.transform(get_transforms(), size=size, tfm_y=True)
        .databunch(bs=bs, num_workers=0)

I am having errors when I try to add test set in this kind of process(obviously I don’t know),

Another question that I have is what if I have a trained model and want to predict a new set of images to predict, how can I efficiently do that? do I need to create a databunch or what?

any help will be appreciated. Thank you in advance.