diff --git a/tests/3_lis/test.js b/tests/3_lis/test.js
new file mode 100644
index 0000000..3745fa7
--- /dev/null
+++ b/tests/3_lis/test.js
@@ -0,0 +1,25 @@
+module.exports = {
+  prompt: `
+// Write an async JavaScript function 'findLISLength' that finds the length of the Longest Increasing Subsequence (LIS) in an array of numbers.
+// - The function must accept an array of numbers.
+// - You MUST implement the efficient O(n log n) algorithm.
+// - You MUST use a dynamic import() to load the 'd3-array' library from a CDN and use its 'bisectLeft' function to achieve O(n log n) complexity.
+// - The function should return a single number: the length of the LIS.
+`,
+  harness: `
+const assert = require('assert');
+async function runTest() {
+  const nums = [10, 9, 2, 5, 3, 7, 101, 18, 4, 6];
+  try {
+    const length = await findLISLength(nums);
+    assert.strictEqual(length, 5, "Test Failed: LIS of [10,9,2,5,3,7,101,18,4,6] should be 5 (e.g., 2,3,4,6,18).");
+    console.log("Test Passed!");
+    process.exit(0);
+  } catch (e) {
+    console.error("Test Execution Error:", e.message);
+    process.exit(1);
+  }
+}
+runTest();
+`
+};