1 files changed, 23 insertions, 0 deletions
diff --git a/Userland/Libraries/LibJS/Tests/ordinary-to-primitive.js b/Userland/Libraries/LibJS/Tests/ordinary-to-primitive.js
new file mode 100644
index 0000000000..176beadb76
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/ordinary-to-primitive.js
@@ -0,0 +1,23 @@
+test("object with custom toString", () => {
+    const o = { toString: () => "foo" };
+    expect(o + "bar").toBe("foobar");
+    expect([o, "bar"].toString()).toBe("foo,bar");
+});
+
+test("object with uncallable toString and custom valueOf", () => {
+    const o = { toString: undefined, valueOf: () => "foo" };
+    expect(o + "bar").toBe("foobar");
+    expect([o, "bar"].toString()).toBe("foo,bar");
+});
+
+test("object with custom valueOf", () => {
+    const o = { valueOf: () => 42 };
+    expect(Number(o)).toBe(42);
+    expect(o + 1).toBe(43);
+});
+
+test("object with uncallable valueOf and custom toString", () => {
+    const o = { valueOf: undefined, toString: () => "42" };
+    expect(Number(o)).toBe(42);
+    expect(o + 1).toBe("421");
+});