class_docstr: Test the Hadamard gradient transform and edge cases such as non diff parameters, auxiliary wires, etc...
class_docstr_tok: ["Test","the","Hadamard","gradient","transform","and","edge","cases","such","as","non","diff","parameters",",","auxiliary","wires",",","etc","..."]
docstr: Test that the transform works correctly when the diff method for every parameter is
  identified to be 0, and that no tapes were generated.
code: def test_all_zero_diff_methods(self):
      """Test that the transform works correctly when the diff method for every parameter is
      identified to be 0, and that no tapes were generated."""
      dev = qml.device("default.qubit", wires=4)
  
      @qml.qnode(dev)
      def circuit(params):
          qml.Rot(*params, wires=0)
          return qml.probs([2, 3])
  
      params = np.array([0.5, 0.5, 0.5], requires_grad=True)
  
      result = qml.gradients.hadamard_grad(circuit)(params)
  
      assert isinstance(result, tuple)
  
      assert len(result) == 3
  
      assert isinstance(result[0], np.ndarray)
      assert result[0].shape == (4,)
      assert np.allclose(result[0], 0)
  
      assert isinstance(result[1], np.ndarray)
      assert result[1].shape == (4,)
      assert np.allclose(result[1], 0)
  
      assert isinstance(result[2], np.ndarray)
      assert result[2].shape == (4,)
      assert np.allclose(result[2], 0)
  
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 23 for calling the TestHadamardGradEdgeCases obj's underlying member method code with example usage: obj.test_all_zero_diff_methods() and returns: qml