diff --git a/tests/tests_codewars/test_doubly_not_less.py b/tests/tests_codewars/test_doubly_not_less.py
new file mode 100644
index 0000000..694e7a4
--- /dev/null
+++ b/tests/tests_codewars/test_doubly_not_less.py
@@ -0,0 +1,27 @@
+from src.codewars.kata_doubly_not_less import doubly_not_less
+import pytest
+
+
+@pytest.mark.parametrize(
+    ("input", "expected"),
+    [
+        ("5314", "5316"),
+        ("23456", "23456"),
+        ("65432", "65437"),
+        ("9998786543", "9998788999"),
+        ("1", "1"),
+        ("1101", "1102"),
+        ("9" * 25, "9" * 25),
+        (
+            "99999999999999999999888888888888877777777777777777766666666666655555555555555555444444444444444",
+            "99999999999999999999888888888888877777777777777777766666666666655555555555999999999999999999999",
+        ),
+        (
+            "569735847563478256235634859346578345634895736459346778",
+            "569735847563478256235634859346578345634895736459346778",
+        ),
+        ("8998989898989889898989898989989899", "8998989898989889898989898989989899"),
+    ],
+)
+def test_doubly_not_less(input, expected):
+    assert doubly_not_less(input) == expected