v3: src/ gets one layout rule and keeps to it — each layer holds one kind of module, and every layer is split into the same domains — the previous pass sorted components into folders but left hooks, helpers and a barrel inside them, kept hooks/, utils/ and contexts/ flat, and still grouped most tests by theme. The rule: components/ holds only components (.tsx), contexts/ holds FooContext.ts + FooProvider.tsx pairs, hooks/ every hook, utils/ every non-React module, pages/ one component per route and nothing else. Each of components/, contexts/, hooks/ and utils/ is split into the same domains — auth, category, chat, comment, dump, editor, feed, form, layout, player, playlist, profile, social, theme, ws — plus shared/ for what belongs to no one domain, so the chat is components/chat, contexts/chat, hooks/chat and utils/chat. components/ui becomes components/shared to match. Out of components/: useApiForm goes to hooks/form, chat's message.ts and time.ts to utils/chat (with chatDraft and chatText, now draft.ts and text.ts), the emoji skin tone to utils/editor, the remembered volume to utils/player; player/icons.tsx is PlayerIcons.tsx. components/form/index.ts is gone: everything is imported from its own file, FormProvider straight from react-hook-form, and expectOk sits beside friendlyFetchError in utils/shared/api.ts (apiError.ts), since pages that have no form used it too. Out of pages/: the index's feed views, tab bar and presence row move to components/feed; HotFeed and NewFeed, identical but for the sort, are one DumpFeed with an order prop, which also takes over MainFeedProps from pages/index/types.ts. App is a named export like everything else. Tests mirror the tree one file per module — test/<layer>/<domain>/<Module>.test.tsx — so the themed files (hooks/misc, data, editor, sync; utils/misc, text, storage, remote, journal; contexts/providers; pages/auth and UserSubpages; layout/Fabs) are split by subject, the setup each piece needs kept and the rest dropped; the floating-button test becomes one test per button, 627 tests now. The README states the rule. No behaviour changes; the catalogues only move their source references.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/test/components/layout/ChatFab.test.tsx

@@ -0,0 +1,57 @@
+import { describe, expect, test, vi } from "vitest";
+import { act, screen } from "@testing-library/react";
+import { ChatFab } from "../../../components/layout/ChatFab.tsx";
+import { ChatContext } from "../../../contexts/chat/ChatContext.ts";
+import { makeSession } from "../../fixtures.ts";
+import { renderWithContexts } from "../../render.tsx";
+
+function withChat(ui: React.ReactNode, openChat = vi.fn()) {
+  return (
+    <ChatContext.Provider
+      value={{ isChatOpen: false, openChat, closeChat: () => {} }}
+    >
+      {ui}
+    </ChatContext.Provider>
+  );
+}
+
+describe("ChatFab", () => {
+  test("guests don't get it", () => {
+    renderWithContexts(withChat(<ChatFab />));
+    expect(screen.queryByRole("button", { hidden: true })).not
+      .toBeInTheDocument();
+  });
+
+  test("shows once the header scrolls away, and opens the chat", () => {
+    const openChat = vi.fn();
+    renderWithContexts(
+      withChat(
+        <>
+          <header className="app-header" />
+          <ChatFab />
+        </>,
+        openChat,
+      ),
+      { session: makeSession(), ws: { unreadChatCount: 2 } },
+    );
+    const header = document.querySelector(".app-header")!;
+    // jsdom lays nothing out: put the header on screen first.
+    header.getBoundingClientRect = () => ({ bottom: 60 }) as DOMRect;
+    act(() => {
+      globalThis.dispatchEvent(new Event("scroll"));
+    });
+    const chat = document.querySelector<HTMLButtonElement>(".chat-fab")!;
+    expect(chat).toHaveAttribute("aria-label", "Chat (2 unread)");
+    expect(chat).toHaveAttribute("aria-hidden", "true");
+    expect(chat).toHaveAttribute("tabindex", "-1");
+
+    header.getBoundingClientRect = () => ({ bottom: -10 }) as DOMRect;
+    act(() => {
+      globalThis.dispatchEvent(new Event("scroll"));
+    });
+    expect(chat).toHaveAttribute("aria-hidden", "false");
+    expect(chat).toHaveClass("chat-fab--visible");
+    act(() => chat.click());
+    expect(openChat).toHaveBeenCalled();
+  });
+});