diff --git a/mlos_bench/mlos_bench/tests/optimizers/conftest.py b/mlos_bench/mlos_bench/tests/optimizers/conftest.py
index aaa6b14753a..9ffed3d80aa 100644
--- a/mlos_bench/mlos_bench/tests/optimizers/conftest.py
+++ b/mlos_bench/mlos_bench/tests/optimizers/conftest.py
@@ -21,24 +21,28 @@ def mock_configs() -> list[dict]:
     """Mock configurations of earlier experiments."""
     return [
         {
+            "123": 2,
             "vmSize": "Standard_B4ms",
             "idle": "halt",
             "kernel_sched_migration_cost_ns": 50000,
             "kernel_sched_latency_ns": 1000000,
         },
         {
+            "123": 1,
             "vmSize": "Standard_B4ms",
             "idle": "halt",
             "kernel_sched_migration_cost_ns": 40000,
             "kernel_sched_latency_ns": 2000000,
         },
         {
+            "123": 3,
             "vmSize": "Standard_B4ms",
             "idle": "mwait",
             "kernel_sched_migration_cost_ns": -1,  # Special value
             "kernel_sched_latency_ns": 3000000,
         },
         {
+            "123": 2,
             "vmSize": "Standard_B2s",
             "idle": "mwait",
             "kernel_sched_migration_cost_ns": 200000,
diff --git a/mlos_bench/mlos_bench/tests/optimizers/mock_opt_test.py b/mlos_bench/mlos_bench/tests/optimizers/mock_opt_test.py
index 05305de50b9..215f55be506 100644
--- a/mlos_bench/mlos_bench/tests/optimizers/mock_opt_test.py
+++ b/mlos_bench/mlos_bench/tests/optimizers/mock_opt_test.py
@@ -18,6 +18,7 @@ def mock_configurations_no_defaults() -> list:
     return [
         (
             {
+                "123": 2,
                 "vmSize": "Standard_B4ms",
                 "idle": "halt",
                 "kernel_sched_migration_cost_ns": 13112,
@@ -27,6 +28,7 @@ def mock_configurations_no_defaults() -> list:
         ),
         (
             {
+                "123": 3,
                 "vmSize": "Standard_B2ms",
                 "idle": "halt",
                 "kernel_sched_migration_cost_ns": 117026,
@@ -36,6 +38,7 @@ def mock_configurations_no_defaults() -> list:
         ),
         (
             {
+                "123": 1,
                 "vmSize": "Standard_B4ms",
                 "idle": "halt",
                 "kernel_sched_migration_cost_ns": 354785,
@@ -52,6 +55,7 @@ def mock_configurations(mock_configurations_no_defaults: list) -> list:
     return [
         (
             {
+                "123": 2,
                 "vmSize": "Standard_B4ms",
                 "idle": "halt",
                 "kernel_sched_migration_cost_ns": -1,
diff --git a/mlos_bench/mlos_bench/tests/optimizers/opt_bulk_register_test.py b/mlos_bench/mlos_bench/tests/optimizers/opt_bulk_register_test.py
index 43ebc7c3915..012d3f5cae0 100644
--- a/mlos_bench/mlos_bench/tests/optimizers/opt_bulk_register_test.py
+++ b/mlos_bench/mlos_bench/tests/optimizers/opt_bulk_register_test.py
@@ -76,6 +76,7 @@ def _test_opt_update_max(
     assert score["score"] == pytest.approx(99.99, 0.01)
     assert tunables is not None
     assert tunables.get_param_values() == {
+        "123": 2,
         "vmSize": "Standard_B2s",
         "idle": "mwait",
         "kernel_sched_migration_cost_ns": 200000,
diff --git a/mlos_bench/mlos_bench/tests/storage/exp_load_test.py b/mlos_bench/mlos_bench/tests/storage/exp_load_test.py
index e07cf80c70a..ac56408551a 100644
--- a/mlos_bench/mlos_bench/tests/storage/exp_load_test.py
+++ b/mlos_bench/mlos_bench/tests/storage/exp_load_test.py
@@ -107,6 +107,7 @@ def test_exp_trial_update_categ(
                 "kernel_sched_latency_ns": "2000000",
                 "kernel_sched_migration_cost_ns": "-1",
                 "vmSize": "Standard_B4ms",
+                "123": 2,
             }
         ],
         [{"score": "99.9", "benchmark": "test"}],
diff --git a/mlos_bench/mlos_bench/tests/tunable_groups_fixtures.py b/mlos_bench/mlos_bench/tests/tunable_groups_fixtures.py
index 003d31c993c..affec0bebb0 100644
--- a/mlos_bench/mlos_bench/tests/tunable_groups_fixtures.py
+++ b/mlos_bench/mlos_bench/tests/tunable_groups_fixtures.py
@@ -66,6 +66,17 @@
                 "log": false
             }
         }
+    },
+    "integer_keyed": {
+        "cost": 0,
+        "params": {
+            "123": {
+                "description": "A parameter with an integer key",
+                "type": "int",
+                "default": 2,
+                "range": [1, 3]
+            }
+        }
     }
 }
 """
diff --git a/mlos_bench/mlos_bench/tests/tunables/tunable_to_configspace_test.py b/mlos_bench/mlos_bench/tests/tunables/tunable_to_configspace_test.py
index 55bc1301226..b3792e73b5b 100644
--- a/mlos_bench/mlos_bench/tests/tunables/tunable_to_configspace_test.py
+++ b/mlos_bench/mlos_bench/tests/tunables/tunable_to_configspace_test.py
@@ -91,6 +91,12 @@ def configuration_space() -> ConfigurationSpace:
                 weights=[0.5, 0.5],
                 default_value=TunableValueKind.SPECIAL,
             ),
+            UniformIntegerHyperparameter(
+                name="123",
+                lower=1,
+                upper=3,
+                default_value=2,
+            ),
         ]
     )
     spaces.add(
diff --git a/mlos_bench/mlos_bench/tests/tunables/tunables_str_test.py b/mlos_bench/mlos_bench/tests/tunables/tunables_str_test.py
index 61514c605bd..5fe73f1a5f3 100644
--- a/mlos_bench/mlos_bench/tests/tunables/tunables_str_test.py
+++ b/mlos_bench/mlos_bench/tests/tunables/tunables_str_test.py
@@ -17,6 +17,17 @@ def test_tunable_groups_str(tunable_groups: TunableGroups) -> None:
     # Same as `tunable_groups` (defined in the `conftest.py` file), but in different order:
     tunables_other = TunableGroups(
         {
+            "integer_keyed": {
+                "cost": 0,
+                "params": {
+                    "123": {
+                        "description": "A parameter with an integer key",
+                        "type": "int",
+                        "default": 2,
+                        "range": [1, 3],
+                    }
+                },
+            },
             "kernel": {
                 "cost": 1,
                 "params": {