add __name__ == '__main__' block in fancy math

src/fancymath/math.py

@@ -12,4 +12,11 @@ def fact(n: int) -> int:
     if n == 1:
         return 1
     else:
-        return n * fact(n - 1)
+        return n * fact(n - 1)
+
+
+if __name__ == '__main__':
+    n = 5
+    assert fact(n) == 120
+    assert add(5, 6) == 11
+    print("Tests passed")