1 files changed, 17 insertions, 0 deletions
diff --git a/test/js/node/util/util.test.js b/test/js/node/util/util.test.js
index 45ecffda8..741b27d19 100644
--- a/test/js/node/util/util.test.js
+++ b/test/js/node/util/util.test.js
@@ -36,6 +36,23 @@ const deepStrictEqual = (...args) => {
 
 // Tests adapted from https://github.com/nodejs/node/blob/main/test/parallel/test-util.js
 describe("util", () => {
+  it("toUSVString", () => {
+    const strings = [
+      // Lone high surrogate
+      "ab\uD800",
+      "ab\uD800c",
+      // Lone low surrogate
+      "\uDFFFab",
+      "c\uDFFFab",
+      // Well-formed
+      "abc",
+      "ab\uD83D\uDE04c",
+    ];
+    const outputs = ["ab�", "ab�c", "�ab", "c�ab", "abc", "ab😄c"];
+    for (let i = 0; i < strings.length; i++) {
+      expect(util.toUSVString(strings[i])).toBe(outputs[i]);
+    }
+  });
   describe("isArray", () => {
     it("all cases", () => {
       strictEqual(util.isArray([]), true);