fix tests

qiskit/circuit/library/standard_gates/x.py

@@ -12,7 +12,7 @@
 
 """X, CX, CCX and multi-controlled X gates."""
 from __future__ import annotations
-from typing import Optional, Union, Type
+from typing import Optional, Union
 from math import ceil, pi
 import numpy
 from qiskit.circuit.controlledgate import ControlledGate
@@ -1101,9 +1101,8 @@ def __new__(
         Depending on the number of controls and which mode of the MCX, this creates an
         explicit CX, CCX, C3X or C4X instance or a generic MCX gate.
         """
-        # The CXGate and CCXGate will be implemented for all modes of the MCX, and
-        # the C3XGate and C4XGate are handled in the gate definition.
-        explicit: dict[int, Type[ControlledGate]] = {1: CXGate, 2: CCXGate}
+        # The CXGate, CCXGate, C3XGate, and C4XGate will be implemented for all modes of the MCX.
+        explicit = {1: CXGate, 2: CCXGate, 3: C3XGate, 4: C4XGate}
         gate_class = explicit.get(num_ctrl_qubits, None)
         if gate_class is not None:
             gate = gate_class.__new__(

test/python/circuit/test_controlled_gate.py

@@ -764,9 +764,9 @@ def test_small_mcx_gates_yield_cx_count(self, num_ctrl_qubits):
 
     @data(1, 2, 3, 4)
     def test_mcxgraycode_gates_yield_explicit_gates(self, num_ctrl_qubits):
-        """Test creating an mcx gate calls MCXGrayCode and yeilds explicit definition."""
+        """Test an MCXGrayCode yields explicit definition."""
         qc = QuantumCircuit(num_ctrl_qubits + 1)
-        qc.mcx(list(range(num_ctrl_qubits)), [num_ctrl_qubits])
+        qc.append(MCXGrayCode(num_ctrl_qubits), list(range(qc.num_qubits)), [])
         explicit = {1: CXGate, 2: CCXGate, 3: C3XGate, 4: C4XGate}
         self.assertEqual(type(qc[0].operation), explicit[num_ctrl_qubits])