diff --git a/tests/y_2023/test_2023_day3.py b/tests/y_2023/test_2023_day3.py
new file mode 100644
index 0000000..232aa3c
--- /dev/null
+++ b/tests/y_2023/test_2023_day3.py
@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from unittest.mock import mock_open, patch
+
+from y_2023.day3 import Day, Number, extract_numbers
+
+with patch("builtins.open", mock_open(read_data="0")):
+    day = Day()
+
+
+def test_extract_numbers():
+    print()
+    res = extract_numbers("467..114..", 0)
+    print(f"{res=}")
+    assert res == [
+        Number(467, 0, 0, 3),
+        Number(114, 0, 5, 3),
+    ]
+    assert extract_numbers("467", 0) == [Number(467, 0, 0, 3)]
+    # assert False
+
+
+def test__preprocess_input():
+    assert True
+
+
+def test_calculate_1():
+    assert True
+
+
+def test_calculate_2():
+    assert True