fix: Support single-register measurements in from_ir (#934)

* fix: add support for measuring a single register in an OpenQASM program

* add round trip transformation test from circuit to OQ3 to circuit

src/braket/circuits/braket_program_context.py

@@ -167,5 +167,6 @@ def add_measure(self, target: tuple[int]) -> None:
         Args:
             target (tuple[int]): the target qubits to be measured.
         """
-        instruction = Instruction(Measure(), list(target))
-        self._circuit.add_instruction(instruction)
+        for index, qubit in enumerate(target):
+            instruction = Instruction(Measure(index=index), qubit)
+            self._circuit.add_instruction(instruction)

test/unit_tests/braket/circuits/test_circuit.py

@@ -811,6 +811,48 @@ def test_from_ir_with_measure():
     assert Circuit.from_ir(source=ir.source, inputs=ir.inputs) == expected_circ
 
 
+def test_from_ir_with_single_measure():
+    ir = OpenQasmProgram(
+        source="\n".join(
+            [
+                "OPENQASM 3.0;",
+                "bit[2] b;",
+                "qubit[2] q;",
+                "h q[0];",
+                "cnot q[0], q[1];",
+                "b = measure q;",
+            ]
+        ),
+        inputs={},
+    )
+    expected_circ = Circuit().h(0).cnot(0, 1).measure(0).measure(1)
+    assert Circuit.from_ir(source=ir.source, inputs=ir.inputs) == expected_circ
+
+
+def test_from_ir_round_trip_transformation():
+    circuit = Circuit().h(0).cnot(0, 1).measure(0).measure(1)
+    ir = OpenQasmProgram(
+        source="\n".join(
+            [
+                "OPENQASM 3.0;",
+                "bit[2] b;",
+                "qubit[2] q;",
+                "h q[0];",
+                "cnot q[0], q[1];",
+                "b[0] = measure q[0];",
+                "b[1] = measure q[1];",
+            ]
+        ),
+        inputs={},
+    )
+    new_ir = circuit.to_ir("OPENQASM")
+    new_circuit = Circuit.from_ir(new_ir)
+
+    assert new_ir == ir
+    assert Circuit.from_ir(source=ir.source, inputs=ir.inputs) == circuit
+    assert new_circuit == circuit
+
+
 def test_add_with_instruction_with_default(cnot_instr):
     circ = Circuit().add(cnot_instr)
     assert circ == Circuit().add_instruction(cnot_instr)