Remove dummy from cirq-core (quantumlib#6356)

* Remove dummy from cirq-core

- Latest best practice advice is to remove all mentions
of the word 'dummy' as it is problematic terminology.

cirq/circuits/qasm_output_test.py

@@ -248,26 +248,26 @@ class UnsupportedOperation(cirq.Operation):
 
 
 def _all_operations(q0, q1, q2, q3, q4, include_measurements=True):
-    class DummyOperation(cirq.Operation):
+    class ExampleOperation(cirq.Operation):
         qubits = (q0,)
         with_qubits = NotImplemented
 
         def _qasm_(self, args: cirq.QasmArgs) -> str:
-            return '// Dummy operation\n'
+            return '// Example operation\n'
 
         def _decompose_(self):
             # Only used by test_output_unitary_same_as_qiskit
             return ()  # pragma: no cover
 
-    class DummyCompositeOperation(cirq.Operation):
+    class ExampleCompositeOperation(cirq.Operation):
         qubits = (q0,)
         with_qubits = NotImplemented
 
         def _decompose_(self):
             return cirq.X(self.qubits[0])
 
         def __repr__(self):
-            return 'DummyCompositeOperation()'
+            return 'ExampleCompositeOperation()'
 
     return (
         cirq.I(q0),
@@ -328,8 +328,8 @@ def __repr__(self):
         )
         if include_measurements
         else (),
-        DummyOperation(),
-        DummyCompositeOperation(),
+        ExampleOperation(),
+        ExampleCompositeOperation(),
     )
 
 
@@ -539,9 +539,9 @@ def filter_unpredictable_numbers(text):
 x q[2];  // Undo the inversion
 measure q[3] -> m_multi[2];
 
-// Dummy operation
+// Example operation
 
-// Operation: DummyCompositeOperation()
+// Operation: ExampleCompositeOperation()
 x q[0];
 """
     )

cirq/contrib/paulistring/clifford_target_gateset_test.py

@@ -182,23 +182,23 @@ def test_already_converted():
 
 
 def test_ignore_unsupported_gate():
-    class UnsupportedDummy(cirq.testing.TwoQubitGate):
+    class UnsupportedGate(cirq.testing.TwoQubitGate):
         pass
 
     q0, q1 = cirq.LineQubit.range(2)
-    c_orig = cirq.Circuit(UnsupportedDummy()(q0, q1), cirq.X(q0) ** sympy.Symbol("theta"))
+    c_orig = cirq.Circuit(UnsupportedGate()(q0, q1), cirq.X(q0) ** sympy.Symbol("theta"))
     c_new = cirq.optimize_for_target_gateset(
         c_orig, gateset=CliffordTargetGateset(), ignore_failures=True
     )
     assert c_new == c_orig
 
 
 def test_fail_unsupported_gate():
-    class UnsupportedDummy(cirq.testing.TwoQubitGate):
+    class UnsupportedGate(cirq.testing.TwoQubitGate):
         pass
 
     q0, q1 = cirq.LineQubit.range(2)
-    c_orig = cirq.Circuit(UnsupportedDummy()(q0, q1))
+    c_orig = cirq.Circuit(UnsupportedGate()(q0, q1))
     with pytest.raises(ValueError):
         _ = cirq.optimize_for_target_gateset(
             c_orig, gateset=CliffordTargetGateset(), ignore_failures=False

cirq/experiments/xeb_fitting_test.py

@@ -129,8 +129,8 @@ def test_benchmark_2q_xeb_fidelities_parallel():
 
 def test_benchmark_2q_xeb_fidelities_vectorized():
     rs = np.random.RandomState(52)
-    dummy_records = [{'pure_probs': rs.rand(4), 'sampled_probs': rs.rand(4)} for _ in range(100)]
-    df = pd.DataFrame(dummy_records)
+    mock_records = [{'pure_probs': rs.rand(4), 'sampled_probs': rs.rand(4)} for _ in range(100)]
+    df = pd.DataFrame(mock_records)
 
     # Using `df.apply` is wayyyy slower than the new implementation!
     # but they should give the same results

cirq/experiments/xeb_sampling.py

@@ -130,7 +130,7 @@ def _verify_two_line_qubits_from_circuits(circuits: Sequence['cirq.Circuit']):
 
 
 class _NoProgress:
-    """Dummy (lack of) tqdm-style progress bar."""
+    """Lack of tqdm-style progress bar."""
 
     def __init__(self, total: int):
         pass

cirq/ops/clifford_gate_test.py

@@ -20,7 +20,7 @@
 import pytest
 
 import cirq
-from cirq.protocols.act_on_protocol_test import DummySimulationState
+from cirq.protocols.act_on_protocol_test import ExampleSimulationState
 from cirq.testing import EqualsTester, assert_allclose_up_to_global_phase
 
 _bools = (False, True)
@@ -47,7 +47,7 @@ def _assert_no_collision(gate) -> None:
 
 
 def _all_rotations():
-    for (pauli, flip) in itertools.product(_paulis, _bools):
+    for pauli, flip in itertools.product(_paulis, _bools):
         yield (pauli, flip)
 
 
@@ -490,7 +490,6 @@ def test_commutes_pauli(gate, pauli, half_turns):
 
 
 def test_to_clifford_tableau_util_function():
-
     tableau = cirq.ops.clifford_gate._to_clifford_tableau(
         x_to=(cirq.X, False), z_to=(cirq.Z, False)
     )
@@ -879,7 +878,7 @@ def test_clifford_gate_act_on_ch_form():
 
 def test_clifford_gate_act_on_fail():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.CliffordGate.X, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.CliffordGate.X, ExampleSimulationState(), qubits=())
 
 
 def test_all_single_qubit_clifford_unitaries():

cirq/ops/common_channels_test.py

@@ -18,7 +18,7 @@
 import pytest
 
 import cirq
-from cirq.protocols.act_on_protocol_test import DummySimulationState
+from cirq.protocols.act_on_protocol_test import ExampleSimulationState
 
 X = np.array([[0, 1], [1, 0]])
 Y = np.array([[0, -1j], [1j, 0]])
@@ -87,7 +87,6 @@ def test_asymmetric_depolarizing_channel_str():
 
 
 def test_asymmetric_depolarizing_channel_eq():
-
     a = cirq.asymmetric_depolarize(0.0099999, 0.01)
     b = cirq.asymmetric_depolarize(0.01, 0.0099999)
     c = cirq.asymmetric_depolarize(0.0, 0.0, 0.0)
@@ -492,7 +491,7 @@ def test_reset_channel_text_diagram():
 
 def test_reset_act_on():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.ResetChannel(), DummySimulationState(), qubits=())
+        cirq.act_on(cirq.ResetChannel(), ExampleSimulationState(), qubits=())
 
     args = cirq.StateVectorSimulationState(
         available_buffer=np.empty(shape=(2, 2, 2, 2, 2), dtype=np.complex64),
@@ -697,7 +696,6 @@ def test_bit_flip_channel_str():
 
 
 def test_bit_flip_channel_eq():
-
     a = cirq.bit_flip(0.0099999)
     b = cirq.bit_flip(0.01)
     c = cirq.bit_flip(0.0)
@@ -735,7 +733,7 @@ def test_bit_flip_channel_text_diagram():
 def test_stabilizer_supports_depolarize():
     with pytest.raises(TypeError, match="act_on"):
         for _ in range(100):
-            cirq.act_on(cirq.depolarize(3 / 4), DummySimulationState(), qubits=())
+            cirq.act_on(cirq.depolarize(3 / 4), ExampleSimulationState(), qubits=())
 
     q = cirq.LineQubit(0)
     c = cirq.Circuit(cirq.depolarize(3 / 4).on(q), cirq.measure(q, key='m'))

cirq/ops/common_gates_test.py

@@ -17,7 +17,7 @@
 import sympy
 
 import cirq
-from cirq.protocols.act_on_protocol_test import DummySimulationState
+from cirq.protocols.act_on_protocol_test import ExampleSimulationState
 
 H = np.array([[1, 1], [1, -1]]) * np.sqrt(0.5)
 HH = cirq.kron(H, H)
@@ -310,7 +310,7 @@ def test_h_str():
 
 def test_x_act_on_tableau():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.X, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.X, ExampleSimulationState(), qubits=())
     original_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=31)
     flipped_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=23)
 
@@ -359,7 +359,7 @@ def _unitary_(self):
 
 def test_y_act_on_tableau():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.Y, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.Y, ExampleSimulationState(), qubits=())
     original_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=31)
     flipped_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=23)
 
@@ -397,9 +397,9 @@ def test_y_act_on_tableau():
 
 def test_z_h_act_on_tableau():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.Z, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.Z, ExampleSimulationState(), qubits=())
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.H, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.H, ExampleSimulationState(), qubits=())
     original_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=31)
     flipped_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=23)
 
@@ -450,7 +450,7 @@ def test_z_h_act_on_tableau():
 
 def test_cx_act_on_tableau():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.CX, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.CX, ExampleSimulationState(), qubits=())
     original_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=31)
 
     state = cirq.CliffordTableauSimulationState(
@@ -494,7 +494,7 @@ def test_cx_act_on_tableau():
 
 def test_cz_act_on_tableau():
     with pytest.raises(TypeError, match="Failed to act"):
-        cirq.act_on(cirq.CZ, DummySimulationState(), qubits=())
+        cirq.act_on(cirq.CZ, ExampleSimulationState(), qubits=())
     original_tableau = cirq.CliffordTableau(num_qubits=5, initial_state=31)
 
     state = cirq.CliffordTableauSimulationState(

cirq/ops/gate_features_test.py

@@ -53,7 +53,7 @@ def test_qasm_output_args_format():
 
 
 def test_multi_qubit_gate_validate():
-    class Dummy(cirq.Gate):
+    class Example(cirq.Gate):
         def _num_qubits_(self) -> int:
             return self._num_qubits
 
@@ -62,7 +62,7 @@ def __init__(self, num_qubits):
 
     a, b, c, d = cirq.LineQubit.range(4)
 
-    g = Dummy(3)
+    g = Example(3)
 
     assert g.num_qubits() == 3
     g.validate_args([a, b, c])

cirq/ops/pauli_string_raw_types_test.py

@@ -48,12 +48,12 @@ def map_qubits(self, qubit_map):
 def test_on_wrong_number_qubits():
     q0, q1, q2 = _make_qubits(3)
 
-    class DummyGate(cirq.PauliStringGateOperation):
+    class ExampleGate(cirq.PauliStringGateOperation):
         def map_qubits(self, qubit_map):
             ps = self.pauli_string.map_qubits(qubit_map)
-            return DummyGate(ps)
+            return ExampleGate(ps)
 
-    g = DummyGate(cirq.PauliString({q0: cirq.X, q1: cirq.Y}))
+    g = ExampleGate(cirq.PauliString({q0: cirq.X, q1: cirq.Y}))
 
     _ = g.with_qubits(q1, q2)
     with pytest.raises(ValueError):

cirq/ops/pauli_string_test.py

@@ -732,11 +732,11 @@ def test_pass_operations_over_cz():
 
 
 def test_pass_operations_over_no_common_qubits():
-    class DummyGate(cirq.testing.SingleQubitGate):
+    class ExampleGate(cirq.testing.SingleQubitGate):
         pass
 
     q0, q1 = _make_qubits(2)
-    op0 = DummyGate()(q1)
+    op0 = ExampleGate()(q1)
     ps_before = cirq.PauliString({q0: cirq.Z})
     ps_after = cirq.PauliString({q0: cirq.Z})
     _assert_pass_over([op0], ps_before, ps_after)

cirq/ops/random_gate_channel_test.py

@@ -219,13 +219,13 @@ def test_stabilizer_supports_probability():
 
 
 def test_unsupported_stabilizer_safety():
-    from cirq.protocols.act_on_protocol_test import DummySimulationState
+    from cirq.protocols.act_on_protocol_test import ExampleSimulationState
 
     with pytest.raises(TypeError, match="act_on"):
         for _ in range(100):
-            cirq.act_on(cirq.X.with_probability(0.5), DummySimulationState(), qubits=())
+            cirq.act_on(cirq.X.with_probability(0.5), ExampleSimulationState(), qubits=())
     with pytest.raises(TypeError, match="act_on"):
-        cirq.act_on(cirq.X.with_probability(sympy.Symbol('x')), DummySimulationState(), qubits=())
+        cirq.act_on(cirq.X.with_probability(sympy.Symbol('x')), ExampleSimulationState(), qubits=())
 
     q = cirq.LineQubit(0)
     c = cirq.Circuit((cirq.X(q) ** 0.25).with_probability(0.5), cirq.measure(q, key='m'))

cirq/ops/raw_types_test.py

@@ -787,9 +787,9 @@ def qubits(self):
             pass
 
     q = cirq.LineQubit(1)
-    from cirq.protocols.act_on_protocol_test import DummySimulationState
+    from cirq.protocols.act_on_protocol_test import ExampleSimulationState
 
-    args = DummySimulationState()
+    args = ExampleSimulationState()
     cirq.act_on(YesActOn()(q).with_tags("test"), args)
     with pytest.raises(TypeError, match="Failed to act"):
         cirq.act_on(NoActOn()(q).with_tags("test"), args)
@@ -798,11 +798,11 @@ def qubits(self):
 
 
 def test_single_qubit_gate_validates_on_each():
-    class Dummy(cirq.testing.SingleQubitGate):
+    class Example(cirq.testing.SingleQubitGate):
         def matrix(self):
             pass
 
-    g = Dummy()
+    g = Example()
     assert g.num_qubits() == 1
 
     test_qubits = [cirq.NamedQubit(str(i)) for i in range(3)]

cirq/protocols/act_on_protocol_test.py

@@ -20,17 +20,17 @@
 import cirq
 
 
-class DummyQuantumState(cirq.QuantumStateRepresentation):
+class ExampleQuantumState(cirq.QuantumStateRepresentation):
     def copy(self, deep_copy_buffers=True):
         pass
 
     def measure(self, axes, seed=None):
         pass
 
 
-class DummySimulationState(cirq.SimulationState):
+class ExampleSimulationState(cirq.SimulationState):
     def __init__(self, fallback_result: Any = NotImplemented):
-        super().__init__(prng=np.random.RandomState(), state=DummyQuantumState())
+        super().__init__(prng=np.random.RandomState(), state=ExampleQuantumState())
         self.fallback_result = fallback_result
 
     def _act_on_fallback_(
@@ -43,18 +43,18 @@ def _act_on_fallback_(
 
 
 def test_act_on_fallback_succeeds():
-    state = DummySimulationState(fallback_result=True)
+    state = ExampleSimulationState(fallback_result=True)
     cirq.act_on(op, state)
 
 
 def test_act_on_fallback_fails():
-    state = DummySimulationState(fallback_result=NotImplemented)
+    state = ExampleSimulationState(fallback_result=NotImplemented)
     with pytest.raises(TypeError, match='Failed to act'):
         cirq.act_on(op, state)
 
 
 def test_act_on_fallback_errors():
-    state = DummySimulationState(fallback_result=False)
+    state = ExampleSimulationState(fallback_result=False)
     with pytest.raises(ValueError, match='_act_on_fallback_ must return True or NotImplemented'):
         cirq.act_on(op, state)
 
@@ -71,7 +71,7 @@ def with_qubits(self, *new_qubits: 'cirq.Qid') -> Self:  # type: ignore[empty-bo
         def _act_on_(self, sim_state):
             return False
 
-    state = DummySimulationState(fallback_result=True)
+    state = ExampleSimulationState(fallback_result=True)
     with pytest.raises(ValueError, match='_act_on_ must return True or NotImplemented'):
         cirq.act_on(Op(), state)
 
@@ -85,14 +85,14 @@ def qubits(self) -> Tuple['cirq.Qid', ...]:  # type: ignore[empty-body]
         def with_qubits(self, *new_qubits: 'cirq.Qid') -> Self:  # type: ignore[empty-body]
             pass
 
-    state = DummySimulationState()
+    state = ExampleSimulationState()
     with pytest.raises(
         ValueError, match='Calls to act_on should not supply qubits if the action is an Operation'
     ):
         cirq.act_on(Op(), state, qubits=[])
 
 
 def test_qubits_should_be_defined_for_operations():
-    state = DummySimulationState()
+    state = ExampleSimulationState()
     with pytest.raises(ValueError, match='Calls to act_on should'):
         cirq.act_on(cirq.KrausChannel([np.array([[1, 0], [0, 0]])]), state, qubits=None)