diff --git a/README.md b/README.md
index e715af5..0d8176d 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,4 @@
 # CI MPM
 Toy repo with some simple functions for the CI lecture
+
+hi
diff --git a/simple_functions/functions1.py b/simple_functions/functions1.py
index 8c63a4d..eae5287 100644
--- a/simple_functions/functions1.py
+++ b/simple_functions/functions1.py
@@ -1,5 +1,7 @@
 
-__all__ = ['my_sum']
+from functools import cache
+
+__all__ = ['my_sum', 'factorial']
 
 
 def my_sum(iterable):
@@ -7,3 +9,8 @@ def my_sum(iterable):
     for i in iterable:
         tot += i
     return tot
+
+
+@cache
+def factorial(n):
+    return n * factorial(n-1) if n else 1
diff --git a/tests/test_simple_functions.py b/tests/test_simple_functions.py
index 5a03b52..1f4494f 100644
--- a/tests/test_simple_functions.py
+++ b/tests/test_simple_functions.py
@@ -1,6 +1,6 @@
 import pytest
 
-from simple_functions import my_sum
+from simple_functions import my_sum, factorial
 
 
 class TestSimpleFunctions(object):
@@ -14,3 +14,13 @@ def test_my_add(self, iterable, expected):
         '''Test our add function'''
         isum = my_sum(iterable)
         assert isum == expected
+    
+    @pytest.mark.parametrize('number, expected', [
+        (5, 120),
+        (3, 6),
+        (1, 1)
+    ])
+    def test_factorial(self, number, expected):
+        '''Test our factorial function'''
+        answer = factorial(number)
+        assert answer == expected