class_docstr: Tests for the density matrix function
class_docstr_tok: ["Tests","for","the","density","matrix","function"]
docstr: Test that the correct density matrix is returned using JAX interface.
docstr_tok: ["Test","that","the","correct","density","matrix","is","returned","using","JAX","interface","."]
code: def test_correct_density_matrix_jax(self, dev_name, diff_method):
      """Test that the correct density matrix is returned using JAX interface."""
      dev = qml.device(dev_name, wires=2)
  
      @qml.qnode(dev, interface="jax", diff_method=diff_method)
      def func():
          qml.Hadamard(wires=0)
          return qml.density_matrix(wires=0)
  
      density_mat = func()
      expected = np.array(
          [[0.5 + 0.0j, 0.5 + 0.0j], [0.5 + 0.0j, 0.5 + 0.0j]]
      )
  
      assert np.allclose(expected, density_mat)
  
      if dev_name != "default.mixed":
          assert np.allclose(
              expected,
              qml.density_matrix(wires=0).process_state(
                  state=dev.state, wire_order=dev.wires
              ),
          )
  
imports: import numpy
  import pytest
  import pennylane
  from pennylane import numpy
  from pennylane.devices import DefaultQubitLegacy
  from pennylane.measurements import State, Shots, density_matrix, expval, state
label_desc: Use image node_id 4 for calling the TestDensityMatrix obj's underlying member method code with example usage: obj.test_correct_density_matrix_jax(dev_name, diff_method) and returns: qml