Could you clarify a bit?
If you can iterate over batches of test data, then you can save them in any way you like: python list, system files, database…?
results = []
for images, labels in test_loader:  # for each batch in test data...
   predictions = my_CNN(images)  # get predictions for this batch
   results.append([images, labels, predictions]) # keep them for further processing

but I assume this is not what you’re after?