Mock the entire localStorage API for each test using Sinon

tests/test-helper.js

@@ -5,17 +5,45 @@ import { forceModulesToBeLoaded, sendCoverage } from 'ember-cli-code-coverage/te
 import { setApplication } from '@ember/test-helpers';
 import { setup as setupQunitDom } from 'qunit-dom';
 import { setup as setupQunitAssertionsExtra } from 'qunit-assertions-extra';
+import setupSinon from 'ember-sinon-qunit';
+import sinon from 'sinon';
 
 import start from 'ember-exam/test-support/start';
 // import { start } from 'ember-qunit';
 
 setApplication(Application.create(config.APP));
 
+setupSinon();
+
 setupQunitDom(QUnit.assert);
 setupQunitAssertionsExtra(QUnit.assert);
 
 QUnit.testStart(function () {
-  window.localStorage.clear(); // We use localStorage for session tokens
+  const localStorageCache = new Map();
+
+  sinon.stub(window.localStorage, 'getItem').callsFake(function (key) {
+    return localStorageCache.get(key);
+  });
+
+  sinon.stub(window.localStorage, 'setItem').callsFake(function (key, value) {
+    localStorageCache.set(key, value);
+  });
+
+  sinon.stub(window.localStorage, 'removeItem').callsFake(function (key) {
+    localStorageCache.delete(key);
+  });
+
+  sinon.stub(window.localStorage, 'clear').callsFake(function () {
+    localStorageCache.clear();
+  });
+
+  sinon.stub(window.localStorage, 'key').callsFake(function (index) {
+    return localStorageCache.key(index);
+  });
+
+  sinon.stub(window.localStorage.__proto__, 'length').get(function () {
+    return localStorageCache.size;
+  });
 });
 
 QUnit.done(async function () {