code: def test_shape(self, batch_size, device, dtype):
      B: int = batch_size
      coeffs = torch.rand(B, 4, device=device, dtype=dtype)
      roots = solver.solve_cubic(coeffs)
      assert roots.shape == (B, 3)
  
file_path: kornia/test/geometry/solvers/test_polynomial_solver.py
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia.geometry.solvers
  from kornia.testing import assert_close
label_desc: Use image node_id 2 for calling the TestCubicSolver obj's underlying member method code with example usage: obj.test_shape(batch_size, device, dtype) without return types