--- a
+++ b/tests/utils/test_utils_data.py
@@ -0,0 +1,39 @@
+from typing import Literal
+
+import pytest
+
+import numpy as np
+
+from moscot.utils.data import (
+    apoptosis_markers,
+    proliferation_markers,
+    transcription_factors,
+)
+
+
+class TestTranscriptionFactor:
+    @pytest.mark.parametrize("organism", ["human", "mouse", "drosophila"])
+    def test_load_data(self, organism: Literal["human", "mouse", "drosophila"]):
+        tfs = transcription_factors(organism=organism)
+        assert isinstance(tfs, list)
+        assert len(tfs) > 0
+        is_str = [isinstance(el, str) for el in tfs]
+        assert np.sum(is_str) == len(tfs)
+
+
+class TestMarkerGenes:
+    @pytest.mark.parametrize("organism", ["human", "mouse"])
+    def test_proliferation_markers(self, organism: Literal["human", "mouse"]):
+        mgs = proliferation_markers(organism=organism)
+        assert isinstance(mgs, list)
+        assert len(mgs) > 0
+        is_str = [isinstance(el, str) for el in mgs]
+        assert np.sum(is_str) == len(mgs)
+
+    @pytest.mark.parametrize("organism", ["human", "mouse"])
+    def test_apoptosis_markers(self, organism: Literal["human", "mouse"]):
+        mgs = apoptosis_markers(organism=organism)
+        assert isinstance(mgs, list)
+        assert len(mgs) > 0
+        is_str = [isinstance(el, str) for el in mgs]
+        assert np.sum(is_str) == len(mgs)