diff --git a/cirq-ionq/cirq_ionq/serializer_test.py b/cirq-ionq/cirq_ionq/serializer_test.py
index 39fb8d0f06d..2ba8ee9b284 100644
--- a/cirq-ionq/cirq_ionq/serializer_test.py
+++ b/cirq-ionq/cirq_ionq/serializer_test.py
@@ -194,7 +194,7 @@ def test_serialize_single_circuit_metadata_is_updated():
     result = serializer.serialize_single_circuit(circuit, metadata={'foo': 'bar'})
     assert result == ionq.SerializedProgram(
         input={'gateset': 'qis', 'qubits': 1, 'circuit': [{'gate': 'x', 'targets': [0]}]},
-        metadata={'foo': 'bar', 'measurement0': 'result\x1f0'},
+        metadata={'foo': 'bar', 'measurement0': f'result{chr(31)}0'},
         settings={},
         compilation={},
         error_mitigation={},
@@ -216,8 +216,8 @@ def test_serialize_many_circuits_metadata_is_updated():
         },
         metadata={
             'foo': 'bar',
-            'measurements': '[{"measurement0": "result\\u001f0"}]',
-            'qubit_numbers': '[1]',
+            'measurements': json.dumps([{"measurement0": f"result{chr(31)}0"}]),
+            'qubit_numbers': json.dumps([1]),
         },
         settings={},
         compilation={},
@@ -824,8 +824,8 @@ def test_serialize_many_circuits_measurement_gate():
     assert result == ionq.SerializedProgram(
         input={'gateset': 'native', 'qubits': 1, 'circuits': [{'circuit': []}]},
         metadata={
-            'measurements': '[{"measurement0": "tomyheart\\u001f0"}]',
-            'qubit_numbers': '[1]',
+            'measurements': json.dumps([{"measurement0": f"tomyheart{chr(31)}0"}]),
+            'qubit_numbers': json.dumps([1]),
         },
         settings={},
         compilation={},
@@ -859,8 +859,8 @@ def test_serialize_many_circuits_measurement_gate_target_order():
     assert result == ionq.SerializedProgram(
         input={'gateset': 'native', 'qubits': 3, 'circuits': [{'circuit': []}]},
         metadata={
-            'measurements': '[{"measurement0": "tomyheart\\u001f2,0"}]',
-            'qubit_numbers': '[3]',
+            'measurements': json.dumps([{"measurement0": f"tomyheart{chr(31)}2,0"}]),
+            'qubit_numbers': json.dumps([3]),
         },
         settings={},
         compilation={},
@@ -991,8 +991,8 @@ def test_serialize_many_circuits_measurement_gate_multiple_keys():
     assert result == ionq.SerializedProgram(
         input={'gateset': 'native', 'qubits': 2, 'circuits': [{'circuit': []}]},
         metadata={
-            'measurements': '[{"measurement0": "a\\u001f0\\u001eb\\u001f1"}]',
-            'qubit_numbers': '[2]',
+            'measurements': json.dumps([{"measurement0": f"a{chr(31)}0{chr(30)}b{chr(31)}1"}]),
+            'qubit_numbers': json.dumps([2]),
         },
         settings={},
         compilation={},
diff --git a/cirq-ionq/cirq_ionq/service_test.py b/cirq-ionq/cirq_ionq/service_test.py
index ce2957c1801..b95fbc8f56e 100644
--- a/cirq-ionq/cirq_ionq/service_test.py
+++ b/cirq-ionq/cirq_ionq/service_test.py
@@ -15,6 +15,7 @@
 from __future__ import annotations
 
 import datetime
+import json
 import os
 from unittest import mock
 
@@ -79,10 +80,10 @@ def test_service_run_batch(target, expected_results1, expected_results2):
         'backend': target,
         'metadata': {
             'shots': '4',
-            'measurements': (
-                "[{\"measurement0\": \"a\\u001f0\"}, {\"measurement0\": \"b\\u001f0\"}]"
+            'measurements': json.dumps(
+                [{"measurement0": f"a{chr(31)}0"}, {"measurement0": f"b{chr(31)}0"}]
             ),
-            'qubit_numbers': '[1, 1]',
+            'qubit_numbers': json.dumps([1, 1]),
         },
         'stats': {'qubits': '1'},
     }
@@ -114,8 +115,10 @@ def test_service_run_batch(target, expected_results1, expected_results2):
     # Serialization induces a float, so we don't validate full circuit.
     assert create_job_kwargs['serialized_program'].input['qubits'] == 1
     assert create_job_kwargs['serialized_program'].metadata == {
-        'measurements': "[{\"measurement0\": \"a\\u001f0\"}, {\"measurement0\": \"b\\u001f0\"}]",
-        'qubit_numbers': '[1, 1]',
+        'measurements': json.dumps(
+            [{"measurement0": f"a{chr(31)}0"}, {"measurement0": f"b{chr(31)}0"}]
+        ),
+        'qubit_numbers': json.dumps([1, 1]),
     }
     assert create_job_kwargs['repetitions'] == 4
     assert create_job_kwargs['target'] == target