For testing dataset without labels in det_lesion_test.py

[LTYUnique]

Thanks for publishing this code.
A question:when I testing dataset without labels in det_lesion_test.py, there were some mistakes in dataset_det.py(phase == 'test').

1. the variable 'test_ptr_pos' was not defined(lines 378);
2. 'self.test_idx' was not initialized(lines 168);
3. When I deleated the variable 'test_ptr_pos' and added the variable 'self.test_idx', there was a mistake ('ZeroDivisionError: integer division or modulo by zero', lines 190) but self.test_size was not zero.

Looking forward to your reply.