class_docstr: Tests that the template is compatible with all interfaces, including the computation
  of gradients.
class_docstr_tok: ["Tests","that","the","template","is","compatible","with","all","interfaces",",","including","the","computation","of","gradients","."]
docstr: Tests the tf interface.
docstr_tok: ["Tests","the","tf","interface","."]
code: def test_tf(self):
      """Tests the tf interface."""
      import tensorflow as tf
  
      dev = qml.device("default.qubit", wires=2)
  
      circuit_default = qml.QNode(manual_rx_circuit, dev)
      circuit_tf = qml.QNode(select_rx_circuit, dev)
  
      input_default = [0.5, 0.2]
      input_tf = tf.Variable(input_default)
  
      assert qml.math.allclose(
          qml.matrix(circuit_default)(input_default),
          qml.matrix(circuit_tf)(input_tf),
      )
      assert (
          qml.math.get_interface(qml.matrix(circuit_tf)(input_tf))
          == "tensorflow"
      )
  
      with tf.GradientTape() as tape:
          res = circuit_default(input_tf)
      grads = tape.gradient(res, [input_tf])
  
      with tf.GradientTape() as tape2:
          res2 = circuit_tf(input_tf)
      grads2 = tape2.gradient(res2, [input_tf])
  
      assert qml.math.allclose(grads[0], grads2[0])
  
imports: import copy
  import pytest
  import numpy
  from pennylane import numpy
  import pennylane
label_desc: Use image node_id 3 for calling the TestInterfaces obj's underlying member method code with example usage: obj.test_tf() without return types