diff --git a/04-recursion/02-unwinding/sum-up-to-solution.js b/04-recursion/02-unwinding/sum-up-to-solution.js
index 45b5ba60..977002e1 100644
--- a/04-recursion/02-unwinding/sum-up-to-solution.js
+++ b/04-recursion/02-unwinding/sum-up-to-solution.js
@@ -1,9 +1,10 @@
 function sumUpTo(n) {
   // Base case - when n is 1, we return 1
-  if (n === 1) {
-    return 1;
+  // Test case - when n is 0, we return 0
+  if (n === 1 || n === 0) {
+    return n;
   }
-
+  
   // Recursive case - when n is greater than 1, we return the sum of n and sumUpTo(n - 1)
   return n + sumUpTo(n - 1);
 }
diff --git a/04-recursion/02-unwinding/sum-up-to-test.js b/04-recursion/02-unwinding/sum-up-to-test.js
index 0df1a4ec..3284813a 100644
--- a/04-recursion/02-unwinding/sum-up-to-test.js
+++ b/04-recursion/02-unwinding/sum-up-to-test.js
@@ -1,3 +1,5 @@
+const sumUpTo = require("./sum-up-to");
+
 test('Summing up positive integers', () => {
   expect(sumUpTo(5)).toBe(15);
   expect(sumUpTo(10)).toBe(55);