diff --git a/workspaces/adventure-pack/goodies/typescript/Number.prototype.chr/index.test.ts b/workspaces/adventure-pack/goodies/typescript/Number.prototype.chr/index.test.ts
new file mode 100644
index 00000000..b4c2be91
--- /dev/null
+++ b/workspaces/adventure-pack/goodies/typescript/Number.prototype.chr/index.test.ts
@@ -0,0 +1,72 @@
+import { describe, expect, it } from "@jest/globals";
+
+import "./index";
+
+describe("Number.prototype.chr", () => {
+  describe("converts ASCII codepoint to ASCII string", () => {
+    it.each([
+      { codepoint: 65, expected: "A" },
+      { codepoint: 10, expected: "\n" },
+      { codepoint: 61, expected: "=" },
+      { codepoint: 126, expected: "~" },
+      { codepoint: 32, expected: " " },
+      { codepoint: 48, expected: "0" },
+    ])(
+      "converts ASCII codepoint $codepoint to ASCII string $expected",
+      ({ codepoint, expected }) => {
+        expect(codepoint.chr()).toBe(expected);
+      },
+    );
+  });
+
+  describe("converts codepoint to emoji", () => {
+    it.each([
+      { codepoint: 129302, expected: "🤖" },
+      { codepoint: 129412, expected: "🦄" },
+    ])(
+      "converts codepoint $codepoint to emoji $expected",
+      ({ codepoint, expected }) => {
+        expect(codepoint.chr()).toBe(expected);
+      },
+    );
+  });
+
+  describe("converts hex codepoint to string", () => {
+    it.each([
+      { codepoint: 0x404, expected: "Є" },
+      { codepoint: 0x24, expected: "$" },
+      { codepoint: 0x1f303, expected: "🌃" },
+      { codepoint: 0x1f92a, expected: "🤪" },
+    ])(
+      "converts hex codepoint $codepoint to string $expected",
+      ({ codepoint, expected }) => {
+        expect(codepoint.chr()).toBe(expected);
+      },
+    );
+  });
+
+  describe("handles edgecases appropiately by returning null char or throwing error.", () => {
+    it("converts zero to null character", () => {
+      expect((0).chr()).toBe("\0");
+    });
+
+    it.each([
+      { edgecase: -1 },
+      { edgecase: 11120651 },
+      { edgecase: Infinity },
+      { edgecase: -Infinity },
+      { edgecase: 1.5 },
+      { edgecase: 1e-2 },
+      { edgecase: 0xffffff },
+    ])(
+      "handles number $edgecase outside unicode range by throwing range error",
+      ({ edgecase }) => {
+        expect(() => edgecase.chr()).toThrow(RangeError);
+      },
+    );
+
+    it("handles incompatible types that resolve to NaN by throwing range error", () => {
+      expect(() => NaN.chr()).toThrow(RangeError);
+    });
+  });
+});