From 536eda42dfbb6d7ad5bef43c5ed1e53637d93c80 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Thu, 24 Dec 2020 11:56:45 -0500
Subject: [PATCH] improve zipper tests (#839)

* improve zipper tests

Co-authored-by: Derk-Jan Karrenbeld <derk-jan+github@karrenbeld.info>
---
 exercises/zipper/zipper.spec.js | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/exercises/zipper/zipper.spec.js b/exercises/zipper/zipper.spec.js
index d3957e5431..6b8e773b9a 100644
--- a/exercises/zipper/zipper.spec.js
+++ b/exercises/zipper/zipper.spec.js
@@ -1,7 +1,5 @@
 import { Zipper } from './zipper';
 
-// Tests adapted from `problem-specifications/zipper/canonical-data.json` @ v1.0.0
-
 function bt(value, left, right) {
   return {
     value,
@@ -74,4 +72,34 @@ describe('Zipper', () => {
   xtest('setValue on deep focus', () => {
     expect(zipper.left().right().setValue(5).toTree()).toEqual(t6);
   });
+
+  xtest('left returns a new Zipper', () => {
+    const left = zipper.left();
+    expect(left).not.toBe(zipper);
+  });
+
+  xtest('right returns a new Zipper', () => {
+    const right = zipper.right();
+    expect(right).not.toBe(zipper);
+  });
+
+  xtest('setValue returns a new Zipper', () => {
+    const anotherZipper = zipper.setValue(99);
+    expect(anotherZipper).not.toBe(zipper);
+  });
+
+  xtest('setRight returns a new Zipper', () => {
+    const right = zipper.setRight(bt(55, null, null));
+    expect(right).not.toBe(zipper);
+  });
+
+  xtest('setLeft returns a new Zipper', () => {
+    const left = zipper.setLeft(bt(55, null, null));
+    expect(left).not.toBe(zipper);
+  });
+
+  xtest('up returns a new Zipper', () => {
+    const up = zipper.right().up();
+    expect(zipper).not.toBe(up);
+  });
 });