Moved test_sum into it's own directory under scripts/

scripts/test_sum/test_sum.js

@@ -0,0 +1,17 @@
+//the test case (js)
+function test_sum(key, val) {
+    function sum(n) {
+        if (n < 2) {
+            return n;
+        }
+
+        return n + sum(n - 1);
+    }
+
+    const result = sum(val);
+    console.log(`${key}: ${result}`);
+}
+
+for (let i = 0; i <= 10; i++) {
+    test_sum(i, i * 1000);
+}