class_docstr: Tests for state vector projector observable.
class_docstr_tok: ["Tests","for","state","vector","projector","observable","."]
code: def test_label_matrices_list_in_cache(self, projector):
      cache = {"matrices": [projector.parameters[0]]}
      assert (
          projector.label(cache=cache) == "P(M1)"
      )  # Does not check repetition (not needed)
      assert len(cache["matrices"]) == 2
      assert np.allclose(cache["matrices"][1], projector.parameters[0])
  
imports: import functools
  import pickle
  import pytest
  import numpy
  from gate_data import I, X, Y, Z, H
  import pennylane
  from pennylane.ops.qubit.observables import BasisStateProjector, StateVectorProjector
label_desc: Use image node_id 7 for calling the TestStateVectorProjector obj's underlying member method code with example usage: obj.test_label_matrices_list_in_cache(projector) without return types