add test cases for utf16 characeters

Author: Uzlopak

test/stringify.test.ts

@@ -58,6 +58,13 @@ test("should omit non-object inputs", () => {
   assert.deepEqual(qs.stringify("hello" as any), "");
 });
 
+test("should handle utf16 characters", () => {
+  assert.deepEqual(qs.stringify({ utf16: "ܩ" }), "utf16=%DC%A9");
+  assert.deepEqual(qs.stringify({ utf16: "睷" }), "utf16=%E7%9D%B7");
+  assert.deepEqual(qs.stringify({ utf16: "aܩ" }), "utf16=a%DC%A9");
+  assert.deepEqual(qs.stringify({ utf16: "a睷" }), "utf16=a%E7%9D%B7");
+});
+
 test("should handle multi-byte characters", () => {
   assert.deepEqual(qs.stringify({ multiByte: "𝌆" }), "multiByte=%F0%9D%8C%86");
 });