diff --git a/src/api/storage.test.ts b/src/api/storage.test.ts
new file mode 100644
index 0000000..8f7a11c
--- /dev/null
+++ b/src/api/storage.test.ts
@@ -0,0 +1,14 @@
+import { loadCredentials, saveCredentials } from "./storage";
+
+import { Player } from "../logic";
+
+test("load missing credentials", () =>
+  expect(loadCredentials("match", Player.Red)).toBe(null));
+
+test("save and load credentials", () => {
+  const matchID = "match";
+  const player = Player.Red;
+  const credentials = "credentials";
+  saveCredentials(matchID, player, credentials);
+  expect(loadCredentials(matchID, player)).toBe(credentials);
+});
diff --git a/src/setupTests.ts b/src/setupTests.ts
index 5fdf001..b0db851 100644
--- a/src/setupTests.ts
+++ b/src/setupTests.ts
@@ -3,3 +3,20 @@
 // expect(element).toHaveTextContent(/react/i)
 // learn more: https://github.com/testing-library/jest-dom
 import "@testing-library/jest-dom/extend-expect";
+
+var localStorageMock = (function () {
+  var storage: any = {};
+  return {
+    getItem: (key: any) => storage[key] || null,
+    setItem: (key: string, value: any) => {
+      storage[key] = value.toString();
+    },
+    clear: () => {
+      storage = {};
+    },
+  };
+})();
+
+Object.defineProperty(window, "localStorage", {
+  value: localStorageMock,
+});