code: #!/usr/bin/env python
  # Python 2/3 compatibility
  from __future__ import print_function
  
  import numpy as np
  import cv2 as cv
  
  from tests_common import NewOpenCVTests
  
  class solvepnp_test(NewOpenCVTests):
  
      def test_regression_16040(self):
          obj_points = np.array([[0, 0, 0], [0, 1, 0], [1, 1, 0], [1, 0, 0]], dtype=np.float32)
          img_points = np.array(
              [[700, 400], [700, 600], [900, 600], [900, 400]], dtype=np.float32
          )
  
          cameraMatrix = np.array(
              [[712.0634, 0, 800], [0, 712.540, 500], [0, 0, 1]], dtype=np.float32
          )
          distCoeffs = np.array([[0, 0, 0, 0]], dtype=np.float32)
          r = np.array([], dtype=np.float32)
          x, r, t, e = cv.solvePnPGeneric(
              obj_points, img_points, cameraMatrix, distCoeffs, reprojectionError=r
          )
  
      def test_regression_16040_2(self):
          obj_points = np.array([[0, 0, 0], [0, 1, 0], [1, 1, 0], [1, 0, 0]], dtype=np.float32)
          img_points = np.array(
              [[[700, 400], [700, 600], [900, 600], [900, 400]]], dtype=np.float32
          )
  
          cameraMatrix = np.array(
              [[712.0634, 0, 800], [0, 712.540, 500], [0, 0, 1]], dtype=np.float32
          )
          distCoeffs = np.array([[0, 0, 0, 0]], dtype=np.float32)
          r = np.array([], dtype=np.float32)
          x, r, t, e = cv.solvePnPGeneric(
              obj_points, img_points, cameraMatrix, distCoeffs, reprojectionError=r
          )
  
      def test_regression_16049(self):
          obj_points = np.array([[0, 0, 0], [0, 1, 0], [1, 1, 0], [1, 0, 0]], dtype=np.float32)
          img_points = np.array(
              [[[700, 400], [700, 600], [900, 600], [900, 400]]], dtype=np.float32
          )
  
          cameraMatrix = np.array(
              [[712.0634, 0, 800], [0, 712.540, 500], [0, 0, 1]], dtype=np.float32
          )
          distCoeffs = np.array([[0, 0, 0, 0]], dtype=np.float32)
          x, r, t, e = cv.solvePnPGeneric(
              obj_points, img_points, cameraMatrix, distCoeffs
          )
          if e is None:
              # noArray() is supported, see https://github.com/opencv/opencv/issues/16049
              pass
          else:
              eDump = cv.utils.dumpInputArray(e)
              self.assertEqual(eDump, "InputArray: empty()=false kind=0x00010000 flags=0x01010000 total(-1)=1 dims(-1)=2 size(-1)=1x1 type(-1)=CV_32FC1")
  
  
  if __name__ == '__main__':
      NewOpenCVTests.bootstrap()
  
apis: numpy.array