--- a
+++ b/tests/test_data_preparation.py
@@ -0,0 +1,20 @@
+import sys
+import os
+import pandas as pd
+
+# Add the '/scripts' directory to the Python path
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '../scripts')))
+
+from data.preparation import feature_selection
+from data.preparation import data_split
+
+# Test feature selection function
+def test_feature_selection():
+    for features in feature_selection().items():
+        assert features
+
+# Test data split function
+def test_data_split():
+    os.makedirs('../../data/input', exist_ok=True)
+
+    assert data_split(feature_selection().drop('LUNG_CANCER', axis='columns'), feature_selection()['LUNG_CANCER'])