diff --git a/tests/4_determinant.js b/tests/4_determinant.js
new file mode 100644
index 0000000..dc1db11
--- /dev/null
+++ b/tests/4_determinant.js
@@ -0,0 +1,25 @@
+module.exports = {
+  prompt: `
+// Write an async JavaScript function 'calculateDeterminant' that calculates the determinant of a square matrix.
+// - The function must accept an n x n matrix, represented as an array of arrays.
+// - You MUST use a dynamic import() to load the 'mathjs' library from a CDN.
+// - You MUST use the library's built-in 'det' function to perform the calculation.
+// - The function should return the determinant value.
+`,
+  harness: `
+const assert = require('assert');
+async function runTest() {
+  const matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
+  try {
+    const det = await calculateDeterminant(matrix);
+    assert.strictEqual(det, 0, "Test Failed: Determinant of [[1,2,3],[4,5,6],[7,8,9]] should be 0.");
+    console.log("Test Passed!");
+    process.exit(0);
+  } catch (e) {
+    console.error("Test Execution Error:", e.message);
+    process.exit(1);
+  }
+}
+runTest();
+`
+};