Mock local storage when running tests

assets/static/__mocks__/localStorageMock.js

@@ -0,0 +1,22 @@
+// source: https://github.com/facebook/jest/issues/2098
+
+var localStorageMock = (function() {
+    var store = {};
+
+    return {
+        getItem: function(key) {
+            return store[key] || null;
+        },
+        setItem: function(key, value) {
+            store[key] = value.toString();
+        },
+        clear: function() {
+            store = {};
+        }
+    };
+
+})();
+
+Object.defineProperty(window, "localStorage", {
+    value: localStorageMock
+});

assets/static/unsee.test.js

@@ -1,6 +1,7 @@
 const $ = require("jquery");
 const templatesMock = require("./__mocks__/templatesMock");
 const alertsMock = require("./__mocks__/alertsMock");
+require("./__mocks__/localStorageMock");
 
 jest.useFakeTimers();