diff --git a/tests/storage/repository/filesystem/special_node/test_lower_case_nodes.py b/tests/storage/repository/filesystem/special_node/test_lower_case_nodes.py
index 058c6b221a..bcd88e1974 100644
--- a/tests/storage/repository/filesystem/special_node/test_lower_case_nodes.py
+++ b/tests/storage/repository/filesystem/special_node/test_lower_case_nodes.py
@@ -9,3 +9,81 @@
 # SPDX-License-Identifier: MPL-2.0
 #
 # This file is part of the Antares project.
+from pathlib import Path
+from unittest.mock import Mock
+
+import pytest
+
+from antarest.study.storage.rawstudy.ini_reader import IniReader
+from antarest.study.storage.rawstudy.model.filesystem.config.model import Area, FileStudyTreeConfig
+from antarest.study.storage.rawstudy.model.filesystem.root.input.bindingconstraints.bindingconstraints_ini import (
+    BindingConstraintsIni,
+)
+from antarest.study.storage.rawstudy.model.filesystem.root.input.renewables.clusters import (
+    ClusteredRenewableClusterConfig,
+)
+from antarest.study.storage.rawstudy.model.filesystem.root.input.st_storage.clusters.area.list import (
+    InputSTStorageAreaList,
+)
+from antarest.study.storage.rawstudy.model.filesystem.root.input.thermal.cluster.area.list import (
+    InputThermalClustersAreaList,
+)
+
+
+@pytest.mark.unit_test
+@pytest.mark.parametrize(
+    "ini_node_cluster_class",
+    [InputSTStorageAreaList, ClusteredRenewableClusterConfig, InputThermalClustersAreaList],
+)
+def test_cluster_ini_list(tmp_path: Path, ini_node_cluster_class):
+    study_path = tmp_path / "study"
+    study_path.mkdir()
+    file_path = study_path / "test.ini"
+    file_path.touch()
+    data = {"Cluster 1": {"group": "Gas"}}
+    area_name = "area_test"
+    area = Area(
+        name=area_name, links={}, thermals=[], renewables=[], filters_synthesis=[], filters_year=[], st_storages=[]
+    )
+    areas = {area_name: area}
+    node = ini_node_cluster_class(
+        context=Mock(),
+        config=FileStudyTreeConfig(study_path=study_path, path=file_path, version=-1, study_id="id", areas=areas),
+        area=area_name,
+    )
+    node.save(data)
+    # Asserts the data is saved correctly
+    ini_content = IniReader().read(file_path)
+    assert ini_content == data
+    # Asserts cluster group and ids are returned in lower case
+    content = node.get([])
+    assert content == {"cluster 1": {"group": "gas"}}
+    # Asserts saving the group in upper case works and that it will be returned in lower case
+    node.save("NUCLEAR", ["cluster 1", "group"])
+    content = node.get([])
+    assert content == {"cluster 1": {"group": "nuclear"}}
+    # Asserts updating the file with an id not in lower case will be done correctly
+    node.save({"params": "43"}, ["Cluster 1"])
+    content = node.get([])
+    assert content == {"cluster 1": {"params": 43}}
+
+
+@pytest.mark.unit_test
+def test_binding_constraint_group_writing(tmp_path: Path):
+    study_path = tmp_path / "study"
+    study_path.mkdir()
+    file_path = study_path / "test.ini"
+    file_path.touch()
+    node = BindingConstraintsIni(
+        context=Mock(),
+        config=FileStudyTreeConfig(study_path=study_path, path=file_path, version=-1, study_id="id"),
+    )
+
+    data = {"0": {"name": "BC_1", "group": "GRP_1"}}
+    node.save(data)
+    # Asserts the data is saved correctly
+    ini_content = IniReader().read(file_path)
+    assert ini_content == data
+    # Asserts the constraint group is returned in lower case
+    content = node.get([])
+    assert content == {"0": {"name": "BC_1", "group": "grp_1"}}