class_docstr: Tests for the validate observables transform.
class_docstr_tok: ["Tests","for","the","validate","observables","transform","."]
docstr: Test that a valid tensor ovservable passes without error.
docstr_tok: ["Test","that","a","valid","tensor","ovservable","passes","without","error","."]
code: def test_valid_tensor_observable(self):
      """Test that a valid tensor ovservable passes without error."""
      tape = QuantumScript(
          [], [qml.expval(qml.PauliZ(0) @ qml.PauliY(1))]
      )
      assert (
          validate_observables(
              tape, lambda obs: obs.name in {"PauliZ", "PauliY"}
          )[0][0]
          is tape
      )
  
imports: import pytest
  import pennylane
  from pennylane.operation import Operation
  from pennylane.tape import QuantumScript
  from pennylane import DeviceError
  from pennylane.devices.preprocess import no_sampling, validate_device_wires, validate_multiprocessing_workers, validate_adjoint_trainable_params, _operator_decomposition_gen, decompose, validate_observables, validate_measurements
label_desc: Use image node_id 3 for calling the TestValidateObservables obj's underlying member method code with example usage: obj.test_valid_tensor_observable() without return types