class_docstr: Test that the user-defined dtype of the device is preserved for QNode
  evaluation
docstr: Test that the default qubit plugin provides correct result for a simple circuit
code: def test_complex_dtype(self, c_dtype, measurement):
      """Test that the default qubit plugin provides correct result for a simple circuit"""
      p = 0.543
  
      dev = qml.device("lightning.qubit", wires=3)
      dev.C_DTYPE = c_dtype
  
      @qml.qnode(dev, diff_method="parameter-shift")
      def circuit(x):
          qml.RX(x, wires=0)
          return qml.apply(measurement)
  
      res = circuit(p)
      assert res.dtype == c_dtype
  
file_path: pennylane/tests/devices/test_lightning_qubit.py
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 2 for calling the TestDtypePreserved obj's underlying member method code with example usage: obj.test_complex_dtype(c_dtype, measurement) and returns: qml