From 5e8c8b983cfc7f893cd327a6dfb38a49f26a82e6 Mon Sep 17 00:00:00 2001
From: Eric Liu <ericyl.us@gmail.com>
Date: Sat, 12 Apr 2025 13:33:30 -0700
Subject: [PATCH] test(local-storage): extract shared global mock

---
 tests/LocalStorage/LocalStorage.test.ts       | 36 +++--------------
 .../LocalStoragePrimitive.test.ts             | 39 ++++---------------
 tests/setup-tests.ts                          | 38 ++++++++++++++++++
 3 files changed, 50 insertions(+), 63 deletions(-)

diff --git a/tests/LocalStorage/LocalStorage.test.ts b/tests/LocalStorage/LocalStorage.test.ts
index 679b1142..d20aaaae 100644
--- a/tests/LocalStorage/LocalStorage.test.ts
+++ b/tests/LocalStorage/LocalStorage.test.ts
@@ -1,35 +1,9 @@
 import { render } from "@testing-library/svelte";
+import { setupLocalStorageMock } from "../setup-tests";
 import LocalStorage from "./LocalStorage.test.svelte";
 
 describe("LocalStorage", () => {
-  let localStorageMock: { [key: string]: string };
-  let originalLocalStorage: Storage;
-
-  beforeEach(() => {
-    originalLocalStorage = global.localStorage;
-    localStorageMock = {};
-    global.localStorage = {
-      getItem: vi.fn((key) => localStorageMock[key] || null),
-      setItem: vi.fn((key, value) => {
-        localStorageMock[key] = value;
-      }),
-      removeItem: vi.fn((key) => {
-        delete localStorageMock[key];
-      }),
-      clear: vi.fn(() => {
-        localStorageMock = {};
-      }),
-      length: 0,
-      key: vi.fn(),
-    };
-  });
-
-  afterEach(() => {
-    global.localStorage = originalLocalStorage;
-    localStorage.clear();
-    vi.restoreAllMocks();
-    localStorageMock = {};
-  });
+  const { setMockItem } = setupLocalStorageMock();
 
   it("saves primitive value to localStorage on mount", () => {
     render(LocalStorage);
@@ -50,7 +24,7 @@ describe("LocalStorage", () => {
   });
 
   it("loads existing primitive value from localStorage", () => {
-    localStorageMock["local-storage-key"] = "existing-value";
+    setMockItem("local-storage-key", "existing-value");
 
     render(LocalStorage);
     expect(localStorage.getItem).toHaveBeenCalledWith("local-storage-key");
@@ -59,7 +33,7 @@ describe("LocalStorage", () => {
   it("loads existing object value from localStorage", () => {
     // Set up existing value
     const existingSettings = { theme: "light", fontSize: 14 };
-    localStorageMock["theme-settings"] = JSON.stringify(existingSettings);
+    setMockItem("theme-settings", JSON.stringify(existingSettings));
 
     render(LocalStorage);
     expect(localStorage.getItem).toHaveBeenCalledWith("theme-settings");
@@ -87,7 +61,7 @@ describe("LocalStorage", () => {
 
   it("handles JSON parse errors gracefully", () => {
     // Set up invalid JSON
-    localStorageMock["local-storage-key"] = "{invalid-json}";
+    setMockItem("local-storage-key", "{invalid-json}");
 
     render(LocalStorage);
     expect(localStorage.getItem).toHaveBeenCalledWith("local-storage-key");
diff --git a/tests/LocalStorage/LocalStoragePrimitive.test.ts b/tests/LocalStorage/LocalStoragePrimitive.test.ts
index 6a80e626..f20a32df 100644
--- a/tests/LocalStorage/LocalStoragePrimitive.test.ts
+++ b/tests/LocalStorage/LocalStoragePrimitive.test.ts
@@ -1,47 +1,22 @@
 import { render } from "@testing-library/svelte";
+import { setupLocalStorageMock } from "../setup-tests";
 import LocalStoragePrimitive from "./LocalStoragePrimitive.test.svelte";
 
 describe("LocalStorage - Primitive Values", () => {
-  let localStorageMock: { [key: string]: string };
-  let originalLocalStorage: Storage;
-  let consoleSpy: any;
+  const { setMockItem } = setupLocalStorageMock();
+  let consoleLog: ReturnType<typeof vi.spyOn>;
 
   beforeEach(() => {
-    originalLocalStorage = global.localStorage;
-    localStorageMock = {};
-    consoleSpy = vi.spyOn(console, "log");
-
-    global.localStorage = {
-      getItem: vi.fn((key) => localStorageMock[key] || null),
-      setItem: vi.fn((key, value) => {
-        localStorageMock[key] = value;
-      }),
-      removeItem: vi.fn((key) => {
-        delete localStorageMock[key];
-      }),
-      clear: vi.fn(() => {
-        localStorageMock = {};
-      }),
-      length: 0,
-      key: vi.fn(),
-    };
-  });
-
-  afterEach(() => {
-    global.localStorage = originalLocalStorage;
-    localStorage.clear();
-    vi.restoreAllMocks();
-    localStorageMock = {};
+    consoleLog = vi.spyOn(console, "log");
   });
 
   it("saves primitive value to localStorage on mount", () => {
     render(LocalStoragePrimitive);
-
     expect(localStorage.setItem).toHaveBeenCalledWith("test-key", "test-value");
   });
 
   it("loads existing primitive value from localStorage", () => {
-    localStorageMock["test-key"] = "existing-value";
+    setMockItem("test-key", "existing-value");
 
     render(LocalStoragePrimitive);
     expect(localStorage.getItem).toHaveBeenCalledWith("test-key");
@@ -49,11 +24,11 @@ describe("LocalStorage - Primitive Values", () => {
 
   it("dispatches save event when setting initial value", () => {
     render(LocalStoragePrimitive);
-    expect(consoleSpy).toHaveBeenCalledWith("save event");
+    expect(consoleLog).toHaveBeenCalledWith("save event");
   });
 
   it("handles invalid values gracefully", () => {
-    localStorageMock["test-key"] = "{invalid-value}";
+    setMockItem("test-key", "{invalid-value}");
 
     render(LocalStoragePrimitive);
     expect(localStorage.getItem).toHaveBeenCalledWith("test-key");
diff --git a/tests/setup-tests.ts b/tests/setup-tests.ts
index 9b36ceec..018fda20 100644
--- a/tests/setup-tests.ts
+++ b/tests/setup-tests.ts
@@ -43,3 +43,41 @@ class ResizeObserverMock {
 global.ResizeObserver = ResizeObserverMock;
 
 export const user = userEvent.setup();
+
+export const setupLocalStorageMock = () => {
+  let localStorageMock: { [key: string]: string } = {};
+  let originalLocalStorage: Storage;
+
+  beforeEach(() => {
+    originalLocalStorage = global.localStorage;
+    localStorageMock = {};
+    global.localStorage = {
+      getItem: vi.fn((key) => localStorageMock[key] || null),
+      setItem: vi.fn((key, value) => {
+        localStorageMock[key] = value;
+      }),
+      removeItem: vi.fn((key) => {
+        delete localStorageMock[key];
+      }),
+      clear: vi.fn(() => {
+        localStorageMock = {};
+      }),
+      length: 0,
+      key: vi.fn(),
+    };
+  });
+
+  afterEach(() => {
+    global.localStorage = originalLocalStorage;
+    localStorage.clear();
+    vi.restoreAllMocks();
+    localStorageMock = {};
+  });
+
+  return {
+    setMockItem: (key: string, value: string) => {
+      localStorageMock[key] = value;
+    },
+    getMockItem: (key: string) => localStorageMock[key],
+  };
+};