diff --git a/lib/dl_api_lib/dl_api_lib_tests/db/control_api/test_rls.py b/lib/dl_api_lib/dl_api_lib_tests/db/control_api/test_rls.py
index 9be5cac80..d3110e453 100644
--- a/lib/dl_api_lib/dl_api_lib_tests/db/control_api/test_rls.py
+++ b/lib/dl_api_lib/dl_api_lib_tests/db/control_api/test_rls.py
@@ -1,5 +1,14 @@
 import pytest
 
+from dl_api_commons.base_models import RequestContextInfo
+from dl_api_lib.dataset.view import DatasetView
+from dl_api_lib.query.formalization.block_formalizer import BlockFormalizer
+from dl_api_lib.query.formalization.legend_formalizer import ResultLegendFormalizer
+from dl_api_lib.query.formalization.raw_specs import (
+    IdFieldRef,
+    RawQuerySpecUnion,
+    RawSelectFieldSpec,
+)
 from dl_api_lib_testing.rls import (
     RLS_CONFIG_CASES,
     config_to_comparable,
@@ -59,3 +68,34 @@ def test_create_rls_from_invalid_config(self, control_api, saved_dataset):
         assert rls_resp.bi_status_code == "ERR.DS_API.RLS.PARSE"
         assert rls_resp.json["message"] == "RLS: Parsing failed at line 2"
         assert rls_resp.json["details"] == {"description": "Wrong format"}
+
+    def test_rls_filter_expr(self, control_api, saved_dataset, sync_us_manager):
+        config = load_rls_config("dl_api_lib_test_config")
+        field_a, field_b = saved_dataset.result_schema[0].id, saved_dataset.result_schema[1].id
+        saved_dataset.rls = {field_a: config, field_b: config}
+        control_api.save_dataset(saved_dataset, fail_ok=False)
+
+        ds = sync_us_manager.get_by_id(saved_dataset.id)
+        sync_us_manager.load_dependencies(ds)
+
+        rci = RequestContextInfo(user_id="user1")
+        raw_query_spec_union = RawQuerySpecUnion(
+            select_specs=[
+                RawSelectFieldSpec(ref=IdFieldRef(id=field_a)),
+                RawSelectFieldSpec(ref=IdFieldRef(id=field_b)),
+            ],
+        )
+        legend = ResultLegendFormalizer(dataset=ds).make_legend(raw_query_spec_union=raw_query_spec_union)
+        block_legend = BlockFormalizer(dataset=ds).make_block_legend(
+            raw_query_spec_union=raw_query_spec_union, legend=legend
+        )
+        ds_view = DatasetView(
+            ds,
+            us_manager=sync_us_manager,
+            block_spec=block_legend.blocks[0],
+            rci=rci,
+        )
+
+        exec_info = ds_view.build_exec_info()
+        src_query = next(iter(exec_info.translated_multi_query.iter_queries()))
+        assert len(src_query.where) == 2  # field_a in ... and field_b in ...
diff --git a/lib/dl_api_lib/dl_api_lib_tests/db/data_api/test_rls.py b/lib/dl_api_lib/dl_api_lib_tests/db/data_api/test_rls.py
index 90e5fcf2e..b6a87f4a4 100644
--- a/lib/dl_api_lib/dl_api_lib_tests/db/data_api/test_rls.py
+++ b/lib/dl_api_lib/dl_api_lib_tests/db/data_api/test_rls.py
@@ -1,7 +1,10 @@
+import re
+
 import pytest
 
+from dl_api_client.dsmaker.shortcuts.result_data import get_data_rows
 from dl_api_lib_testing.app import TestingSubjectResolver
-from dl_api_lib_testing.rls import MAIN_TEST_CASE
+from dl_api_lib_testing.rls import load_rls_config
 from dl_api_lib_tests.db.base import DefaultApiTestBase
 
 
@@ -9,8 +12,8 @@ class TestRLS(DefaultApiTestBase):
     @pytest.fixture(scope="function")
     def dataset_with_rls(self, control_api, saved_dataset):
         ds = saved_dataset
-        field_guid = ds.result_schema[0].id
-        ds.rls = {field_guid: MAIN_TEST_CASE["config"]}
+        field_guid = ds.result_schema[1].id
+        ds.rls = {field_guid: load_rls_config("dl_api_lib_test_config")}
 
         control_api.save_dataset(ds, fail_ok=False)
         resp = control_api.load_dataset(ds)
@@ -25,13 +28,16 @@ def get_subjects_by_names_mock(self, names):
         rls_val_modifier = "\n'x': *\n" if modify_rls else ""
         ds.rls = {key: val + rls_val_modifier for key, val in ds.rls.items() if val}
         monkeypatch.setattr(TestingSubjectResolver, "get_subjects_by_names", get_subjects_by_names_mock)
-        return data_api.get_preview(dataset=ds, limit=13, fail_ok=True)
+        return data_api.get_preview(dataset=ds, fail_ok=True)
 
     def test_preview_with_saved_rls(self, dataset_with_rls, data_api, monkeypatch):
         resp = self._get_rls_preview_response(dataset_with_rls, data_api, monkeypatch, modify_rls=False)
-        resp_data = resp.json
-        assert resp.status_code == 200, resp_data
-        assert resp_data
+        assert resp.status_code == 200, resp.json
+
+        rls_data = [row[1] for row in get_data_rows(resp)]
+        assert rls_data
+        # ensure all values from the RLS config are presented and no other values are
+        assert set(rls_data) == set(re.findall("'(.+?)'", load_rls_config("dl_api_lib_test_config")))
 
     def test_preview_with_updated_rls(self, dataset_with_rls, data_api, monkeypatch):
         resp = self._get_rls_preview_response(dataset_with_rls, data_api, monkeypatch, modify_rls=True)
diff --git a/lib/dl_api_lib_testing/dl_api_lib_testing/app.py b/lib/dl_api_lib_testing/dl_api_lib_testing/app.py
index 9daa920f7..8043eb680 100644
--- a/lib/dl_api_lib_testing/dl_api_lib_testing/app.py
+++ b/lib/dl_api_lib_testing/dl_api_lib_testing/app.py
@@ -105,15 +105,29 @@ def rqe_config_subprocess_cm(self) -> Generator[RQEConfig, None, None]:
 @attr.s
 class TestingSubjectResolver(BaseSubjectResolver):
     def get_subjects_by_names(self, names: list[str]) -> list[RLSSubject]:
-        """Mock resolver. Considers a user real if his name starts with 'user'"""
-        return [
-            RLSSubject(
-                subject_id="",
-                subject_type=RLSSubjectType.user if name.startswith("user") else RLSSubjectType.notfound,
-                subject_name=name if name.startswith("user") else RLS_FAILED_USER_NAME_PREFIX + name,
-            )
-            for name in names
-        ]
+        """
+        Mock resolver. Considers a user real if the name starts with a 'user' or
+        if it's equals to '_the_tests_asyncapp_user_name_'
+        """
+        subjects = []
+        for name in names:
+            if name == "_the_tests_asyncapp_user_name_":
+                subjects.append(
+                    RLSSubject(
+                        subject_id="_the_tests_asyncapp_user_id_",
+                        subject_type=RLSSubjectType.user,
+                        subject_name=name,
+                    )
+                )
+            else:
+                subjects.append(
+                    RLSSubject(
+                        subject_id="",
+                        subject_type=RLSSubjectType.user if name.startswith("user") else RLSSubjectType.notfound,
+                        subject_name=name if name.startswith("user") else RLS_FAILED_USER_NAME_PREFIX + name,
+                    )
+                )
+        return subjects
 
 
 @attr.s
diff --git a/lib/dl_api_lib_testing/dl_api_lib_testing/rls.py b/lib/dl_api_lib_testing/dl_api_lib_testing/rls.py
index 00b77206e..ff264406f 100644
--- a/lib/dl_api_lib_testing/dl_api_lib_testing/rls.py
+++ b/lib/dl_api_lib_testing/dl_api_lib_testing/rls.py
@@ -62,7 +62,6 @@ def load_rls(name: str) -> list[RLSEntry]:
         rls_entries_updated=load_rls("missing_login_updated.json"),
     ),
 ]
-MAIN_TEST_CASE = RLS_CONFIG_CASES[0]
 
 
 def config_to_comparable(conf: str):
diff --git a/lib/dl_api_lib_testing/dl_api_lib_testing/test_data/rls_configs/dl_api_lib_test_config b/lib/dl_api_lib_testing/dl_api_lib_testing/test_data/rls_configs/dl_api_lib_test_config
new file mode 100644
index 000000000..274ed7279
--- /dev/null
+++ b/lib/dl_api_lib_testing/dl_api_lib_testing/test_data/rls_configs/dl_api_lib_test_config
@@ -0,0 +1,2 @@
+'Naperville': _the_tests_asyncapp_user_name_
+'Philadelphia': *