class_docstr: Unit tests for clifford compilation function.
class_docstr_tok: ["Unit","tests","for","clifford","compilation","function","."]
docstr: Test that global phase operation is added only when it is non-zero
docstr_tok: ["Test","that","global","phase","operation","is","added","only","when","it","is","non-zero"]
code: def test_zero_global_phase(self):
      """Test that global phase operation is added only when it is non-zero"""
  
      with qml.tape.QuantumTape() as tape:
          qml.CNOT([0, 1])
  
      [tape], _ = qml.clifford_t_decomposition(tape)
  
      assert not sum(
          [isinstance(op, qml.GlobalPhase) for op in tape.operations]
      )
  
imports: import math
  from functools import reduce
  import pytest
  import pennylane
  from pennylane.transforms.decompositions.clifford_t_transform import check_clifford_t, clifford_t_decomposition, _rot_decompose, _one_qubit_decompose, _two_qubit_decompose, _CLIFFORD_T_GATES
  from pennylane.transforms.optimization.optimization_utils import _fuse_global_phases
label_desc: Use image node_id 10 for calling the TestCliffordCompile obj's underlying member method code with example usage: obj.test_zero_global_phase() without return types