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 an empty circuit works correctly
code: def test_empty_circuit(self):
      """Test that an empty circuit works correctly"""
      with qml.queuing.AnnotatedQueue() as q:
          qml.expval(qml.PauliZ(0))
  
      tape = qml.tape.QuantumScript.from_queue(q)
      with pytest.warns(
          UserWarning,
          match="gradient of a tape with no trainable parameters",
      ):
          tapes, _ = qml.gradients.hadamard_grad(tape)
      assert not tapes
  
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 6 for calling the TestHadamardGradEdgeCases obj's underlying member method code with example usage: obj.test_empty_circuit() without return types