def test_prune_tensors_no_pruning_took_place(self, mock_device):
"""Test that the _prune_tensors auxiliary method returns
the original tensor if no observables were pruned."""
px = qml.PauliX(1)
obs = px
def circuit(x):
return qml.expval(obs)
qnode = BaseQNode(circuit, mock_device)
assert qnode._prune_tensors(obs) == px
def test_prune_tensors(self, mock_device):
"""Test that the _prune_tensors auxiliary method prunes correct for
a single Identity in the Tensor."""
px = qml.PauliX(1)
obs = qml.Identity(0) @ px
def circuit(x):
return qml.expval(obs)
qnode = BaseQNode(circuit, mock_device)
assert qnode._prune_tensors(obs) == px
