test: Add unit tests for linkPreviewSettings.js

- Added comprehensive tests for default settings, storage parsing, and error handling.
- Covered `setLinkPreviewAutoFetch` and `allowLinkPreviewDomain` (including normalization and silent mode).
- Verified `isLinkPreviewDomainAllowed` and event subscriptions.
- Mocked `window.dispatchEvent`, `addEventListener`, and `CustomEvent` locally as they are missing from test helpers.

Co-authored-by: PR0M3TH3AN <[email protected]>

tests/link-preview-settings.test.mjs

@@ -0,0 +1,199 @@
+import test, { beforeEach } from "node:test";
+import assert from "node:assert/strict";
+
+// Mock Event if not present (unlikely in Node 22, but safe)
+if (typeof globalThis.Event === "undefined") {
+  globalThis.Event = class Event {
+    constructor(type, options = {}) {
+      this.type = type;
+      this.bubbles = !!options.bubbles;
+      this.cancelable = !!options.cancelable;
+    }
+  };
+}
+
+// Mock CustomEvent if not present (Node environment)
+if (typeof globalThis.CustomEvent === "undefined") {
+  globalThis.CustomEvent = class CustomEvent extends globalThis.Event {
+    constructor(type, options = {}) {
+      super(type, options);
+      this.detail = options.detail || null;
+    }
+  };
+}
+
+// Mock EventTarget methods on window if not present
+// setup-localstorage.mjs provides window object but not these methods
+if (typeof window.dispatchEvent === "undefined") {
+  const listeners = new Map();
+
+  window.addEventListener = (type, handler) => {
+    if (!listeners.has(type)) {
+      listeners.set(type, new Set());
+    }
+    listeners.get(type).add(handler);
+  };
+
+  window.removeEventListener = (type, handler) => {
+    if (listeners.has(type)) {
+      listeners.get(type).delete(handler);
+    }
+  };
+
+  window.dispatchEvent = (event) => {
+    const type = event.type;
+    if (listeners.has(type)) {
+      for (const handler of listeners.get(type)) {
+        handler(event);
+      }
+      return true;
+    }
+    return false;
+  };
+
+  // Helper to clear listeners between tests
+  window._clearListeners = () => listeners.clear();
+}
+
+// Import the module under test
+import {
+  getLinkPreviewSettings,
+  setLinkPreviewAutoFetch,
+  allowLinkPreviewDomain,
+  isLinkPreviewDomainAllowed,
+  subscribeToLinkPreviewSettings,
+} from "../js/utils/linkPreviewSettings.js";
+
+beforeEach(() => {
+  window.localStorage.clear();
+  if (window._clearListeners) window._clearListeners();
+});
+
+test("getLinkPreviewSettings returns default settings when storage is empty", () => {
+  const settings = getLinkPreviewSettings();
+  assert.equal(settings.autoFetchUnknownDomains, true);
+  assert.deepEqual(settings.allowedDomains, []);
+});
+
+test("getLinkPreviewSettings parses stored settings correctly", () => {
+  const stored = {
+    autoFetchUnknownDomains: false,
+    allowedDomains: ["example.com", "test.org"],
+  };
+  window.localStorage.setItem("bitvid:linkPreviewSettings:v1", JSON.stringify(stored));
+
+  const settings = getLinkPreviewSettings();
+  assert.equal(settings.autoFetchUnknownDomains, false);
+  assert.deepEqual(settings.allowedDomains, ["example.com", "test.org"]);
+});
+
+test("getLinkPreviewSettings handles corrupted JSON", () => {
+  window.localStorage.setItem("bitvid:linkPreviewSettings:v1", "{invalid-json");
+
+  const settings = getLinkPreviewSettings();
+  assert.equal(settings.autoFetchUnknownDomains, true); // Fallback to default
+  assert.deepEqual(settings.allowedDomains, []);
+});
+
+test("getLinkPreviewSettings sanitizes invalid types in storage", () => {
+  const invalidTypes = {
+    autoFetchUnknownDomains: "invalid-string", // Should be boolean
+    allowedDomains: "not-an-array", // Should be array
+  };
+  window.localStorage.setItem("bitvid:linkPreviewSettings:v1", JSON.stringify(invalidTypes));
+
+  const settings = getLinkPreviewSettings();
+  assert.equal(settings.autoFetchUnknownDomains, true); // Default
+  assert.deepEqual(settings.allowedDomains, []); // Default
+});
+
+test("getLinkPreviewSettings handles non-object JSON", () => {
+  window.localStorage.setItem("bitvid:linkPreviewSettings:v1", "123");
+
+  const settings = getLinkPreviewSettings();
+  assert.equal(settings.autoFetchUnknownDomains, true);
+  assert.deepEqual(settings.allowedDomains, []);
+});
+
+test("setLinkPreviewAutoFetch updates setting and persists", () => {
+  const newSettings = setLinkPreviewAutoFetch(false);
+  assert.equal(newSettings.autoFetchUnknownDomains, false);
+
+  const stored = JSON.parse(window.localStorage.getItem("bitvid:linkPreviewSettings:v1"));
+  assert.equal(stored.autoFetchUnknownDomains, false);
+});
+
+test("setLinkPreviewAutoFetch emits event", () => {
+  return new Promise((resolve, reject) => {
+    subscribeToLinkPreviewSettings((e) => {
+      try {
+        assert.equal(e.detail.settings.autoFetchUnknownDomains, false);
+        resolve();
+      } catch (err) {
+        reject(err);
+      }
+    });
+    setLinkPreviewAutoFetch(false);
+  });
+});
+
+test("allowLinkPreviewDomain adds domain and persists", () => {
+  let settings = allowLinkPreviewDomain("example.com");
+  assert.deepEqual(settings.allowedDomains, ["example.com"]);
+
+  settings = allowLinkPreviewDomain("TEST.ORG"); // Should normalize
+  assert.deepEqual(settings.allowedDomains, ["example.com", "test.org"]);
+
+  const stored = JSON.parse(window.localStorage.getItem("bitvid:linkPreviewSettings:v1"));
+  assert.deepEqual(stored.allowedDomains, ["example.com", "test.org"]);
+});
+
+test("allowLinkPreviewDomain ignores duplicates", () => {
+  allowLinkPreviewDomain("example.com");
+  const settings = allowLinkPreviewDomain("example.com");
+  assert.deepEqual(settings.allowedDomains, ["example.com"]);
+});
+
+test("allowLinkPreviewDomain respects silent option", () => {
+  let eventEmitted = false;
+  subscribeToLinkPreviewSettings(() => {
+    eventEmitted = true;
+  });
+
+  allowLinkPreviewDomain("silent.com", { silent: true });
+  assert.equal(eventEmitted, false);
+
+  const settings = getLinkPreviewSettings();
+  assert.ok(settings.allowedDomains.includes("silent.com"));
+});
+
+test("isLinkPreviewDomainAllowed checks against settings", () => {
+  allowLinkPreviewDomain("allowed.com");
+
+  assert.equal(isLinkPreviewDomainAllowed("allowed.com"), true);
+  assert.equal(isLinkPreviewDomainAllowed("ALLOWED.COM"), true); // Case insensitive
+  assert.equal(isLinkPreviewDomainAllowed("blocked.com"), false);
+});
+
+test("isLinkPreviewDomainAllowed checks against provided settings", () => {
+  const customSettings = {
+    allowedDomains: ["custom.com"],
+  };
+
+  assert.equal(isLinkPreviewDomainAllowed("custom.com", customSettings), true);
+  assert.equal(isLinkPreviewDomainAllowed("other.com", customSettings), false);
+});
+
+test("subscribeToLinkPreviewSettings returns unsubscribe function", () => {
+  let callCount = 0;
+  const unsubscribe = subscribeToLinkPreviewSettings(() => {
+    callCount++;
+  });
+
+  setLinkPreviewAutoFetch(false);
+  assert.equal(callCount, 1);
+
+  unsubscribe();
+  setLinkPreviewAutoFetch(true);
+  assert.equal(callCount, 1); // Should not increase
+});