code: def setUp(self):
      img = np.zeros((15, 30, 3))
      polygon = [
          np.array([10.0, 5.0, 20.0, 5.0, 20.0, 10.0, 10.0, 10.0])
      ]
      bbox = np.array([[10.0, 5.0, 20.0, 10.0]])
      self.data_info = dict(
          img=img, gt_polygons=polygon, gt_bboxes=bbox
      )
  
imports: import copy
  import unittest
  import unittest.mock
  import numpy
  from mmcv.transforms import Pad, RandomResize
  from mmocr.datasets.transforms import BoundedScaleAspectJitter, RandomCrop, RandomFlip, Resize, ShortScaleAspectJitter, SourceImagePad, TextDetRandomCrop, TextDetRandomCropFlip
  from mmocr.utils import bbox2poly, poly2shapely
label_desc: Use image node_id 1 for calling the TestSourceImagePad obj's underlying member method code with example usage: obj.setUp() without return types