class_docstr: Unit tests for the ``qml.vn_entropy`` function.
docstr: Tests the output of qml.vn_entropy
docstr_tok: ["Tests","the","output","of","qml.vn_entropy"]
code: def test_vn_entropy(self, interface, state_vector, expected):
      """Tests the output of qml.vn_entropy"""
      dev = qml.device("default.qubit.legacy", wires=2)
  
      @qml.qnode(dev, interface=interface)
      def circuit():
          qml.StatePrep(state_vector, wires=[0, 1])
          return qml.vn_entropy(wires=0)
  
      res = circuit()
      new_res = qml.vn_entropy(wires=0).process_state(
          state=circuit.device.state, wire_order=circuit.device.wires
      )
      assert qml.math.allclose(res, expected)
      assert qml.math.allclose(new_res, expected)
      assert (
          INTERFACE_MAP.get(qml.math.get_interface(new_res))
          == interface
      )
      assert res.dtype == new_res.dtype
  
imports: import numpy
  import pytest
  import pennylane
  from pennylane.workflow import INTERFACE_MAP
  from pennylane.measurements import Shots
  from pennylane.measurements.vn_entropy import VnEntropyMP
label_desc: Use image node_id 1 for calling the TestInitialization obj's underlying member method code with example usage: obj.test_vn_entropy(interface, state_vector, expected) and returns: qml