class_docstr: Test that wire lines are produced correctly in different situations.
class_docstr_tok: ["Test","that","wire","lines","are","produced","correctly","in","different","situations","."]
docstr: Test situation with empty tape but specified wires and show_all_wires
  still draws wires.
code: def test_empty_tape_wire_order(self):
      """Test situation with empty tape but specified wires and show_all_wires
      still draws wires."""
  
      _, ax = tape_mpl(
          QuantumScript(), wire_order=[0, 1, 2], show_all_wires=True
      )
  
      assert len(ax.lines) == 3
      for wire, line in enumerate(ax.lines):
          assert line.get_xdata() == (
              -1,
              1,
          )  # from -1 to number of layers
          assert line.get_ydata() == (wire, wire)
  
      plt.close()
  
imports: import pytest
  import pennylane
  from pennylane.drawer import tape_mpl
  from pennylane.tape import QuantumScript
label_desc: Use image node_id 1 for calling the TestWires obj's underlying member method code with example usage: obj.test_empty_tape_wire_order() without return types