diff --git a/web/tests/room-session.test.js b/web/tests/room-session.test.js
new file mode 100644
index 0000000..eb0914d
--- /dev/null
+++ b/web/tests/room-session.test.js
@@ -0,0 +1,265 @@
+// The online screen's request machine, extracted so its two failure modes —
+// a stale resume token that never gets an answer, and a lobby action the
+// socket refused — are things this file can prove directly, without a
+// mounted page or a real socket.
+
+import { describe, expect, it } from 'vitest';
+import { createRoomSession } from '../src/lib/stores/room-session.svelte.js';
+
+/** Records what reached the socket for each request kind. */
+function senders(accepted = true) {
+	/** @type {string[]} */
+	const sent = [];
+	return {
+		sent,
+		create: () => {
+			sent.push('create');
+			return accepted;
+		},
+		join: (/** @type {string} */ code) => {
+			sent.push(`join:${code}`);
+			return accepted;
+		},
+		quickMatch: () => {
+			sent.push('quickMatch');
+			return accepted;
+		}
+	};
+}
+
+describe('joining or creating a room', () => {
+	it('holds the request until the socket is open', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.request({ kind: 'create' });
+		expect(session.flush(false, s)).toBe(false);
+		expect(s.sent).toEqual([]);
+
+		expect(session.flush(true, s)).toBe(true);
+		expect(s.sent).toEqual(['create']);
+		expect(session.state.pending).toBeNull();
+	});
+
+	it('sends a join with its room code', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.request({ kind: 'join', code: 'K7M2QP' });
+		session.flush(true, s);
+
+		expect(s.sent).toEqual(['join:K7M2QP']);
+	});
+
+	it('holds a refused request so the next open connection carries it', () => {
+		const refused = senders(false);
+		const session = createRoomSession();
+
+		session.request({ kind: 'create' });
+		expect(session.flush(true, refused)).toBe(false);
+		expect(session.flush(true, refused)).toBe(false);
+
+		expect(refused.sent).toEqual(['create', 'create']);
+		expect(session.state.pending).not.toBeNull();
+	});
+
+	it('keeps only the latest request when asked twice before sending', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.request({ kind: 'create' });
+		session.request({ kind: 'quickMatch' });
+		session.flush(true, s);
+
+		expect(s.sent).toEqual(['quickMatch']);
+	});
+
+	it('clears every latch a fresh request opens with', () => {
+		const session = createRoomSession();
+		session.setNeedName(true);
+		session.setStalled(true);
+
+		session.request({ kind: 'create' });
+
+		expect(session.state.needName).toBe(false);
+		expect(session.state.stalled).toBe(false);
+		expect(session.state.resuming).toBe(false);
+	});
+});
+
+describe('resuming a stored session', () => {
+	it('holds a request behind the resume and refuses to send it while resuming', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.startResume();
+		session.holdPendingJoin({ kind: 'join', code: 'K7M2QP' });
+
+		expect(session.flush(true, s)).toBe(false);
+		expect(s.sent).toEqual([]);
+	});
+
+	it('spends the held join once the resume lands in a room', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.startResume();
+		session.holdPendingJoin({ kind: 'join', code: 'K7M2QP' });
+		session.noteRoom();
+
+		expect(session.state.resuming).toBe(false);
+		// Arriving in a room answers the held code too — it is not sent
+		// afterwards as a second, redundant join.
+		expect(session.state.pending).toBeNull();
+		expect(session.flush(true, s)).toBe(false);
+		expect(s.sent).toEqual([]);
+	});
+
+	it('times out to the join form instead of staying stuck forever', () => {
+		// The scenario C1 in the review describes: an older server answers a
+		// stale token with silence, never with an error.
+		const session = createRoomSession();
+
+		session.startResume();
+		session.noteResumeFailed(/* named */ true);
+
+		expect(session.state.resuming).toBe(false);
+		expect(session.state.resumeFailed).toBe(true);
+	});
+
+	it('does nothing if the resume already resolved before the timer fired', () => {
+		const session = createRoomSession();
+
+		session.startResume();
+		session.noteRoom();
+		session.noteResumeFailed(true);
+
+		// noteRoom() already cleared resuming; the stale timer callback must
+		// not reopen the failure state on top of a resume that succeeded.
+		expect(session.state.resumeFailed).toBe(false);
+	});
+
+	it('asks for a name instead of spending an invite code held behind a failed resume', () => {
+		const session = createRoomSession();
+
+		session.startResume();
+		session.holdPendingJoin({ kind: 'join', code: 'K7M2QP' });
+		session.noteResumeFailed(/* named */ false);
+
+		expect(session.state.needName).toBe(true);
+		expect(session.state.pending).toBeNull();
+	});
+
+	it('keeps a held join when the player already has a name, so it flushes next', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.startResume();
+		session.holdPendingJoin({ kind: 'join', code: 'K7M2QP' });
+		session.noteResumeFailed(/* named */ true);
+
+		expect(session.state.needName).toBe(false);
+		expect(session.flush(true, s)).toBe(true);
+		expect(s.sent).toEqual(['join:K7M2QP']);
+	});
+});
+
+describe('quick match', () => {
+	it('goes from queued to seated the same way a plain request does', () => {
+		const s = senders();
+		const session = createRoomSession();
+
+		session.request({ kind: 'quickMatch' });
+		expect(session.flush(true, s)).toBe(true);
+		expect(s.sent).toEqual(['quickMatch']);
+
+		session.resetQueued();
+		session.tickQueued();
+		session.tickQueued();
+		expect(session.state.queuedForS).toBe(2);
+
+		// RoomState arriving is what a match found looks like from here.
+		session.noteRoom();
+		expect(session.state.pending).toBeNull();
+	});
+
+	it('counts seconds only from the moment counting starts', () => {
+		const session = createRoomSession();
+		session.tickQueued();
+		expect(session.state.queuedForS).toBe(1);
+		session.resetQueued();
+		expect(session.state.queuedForS).toBe(0);
+	});
+});
+
+describe('held room actions', () => {
+	/** @param {boolean} accepted */
+	function dispatcher(accepted = true) {
+		/** @type {import('../src/lib/stores/room-session.svelte.js').RoomAction[]} */
+		const sent = [];
+		return {
+			sent,
+			/** @param {import('../src/lib/stores/room-session.svelte.js').RoomAction} action */
+			dispatch: (action) => {
+				sent.push(action);
+				return accepted;
+			}
+		};
+	}
+
+	it('does nothing when nothing is held', () => {
+		const d = dispatcher();
+		const session = createRoomSession();
+
+		expect(session.flushAction(true, d.dispatch)).toBe(false);
+		expect(d.sent).toEqual([]);
+	});
+
+	it('resends a held action once the socket reopens', () => {
+		const d = dispatcher();
+		const session = createRoomSession();
+
+		session.holdAction({ kind: 'setReady', ready: true });
+		expect(session.flushAction(false, d.dispatch)).toBe(false);
+		expect(d.sent).toEqual([]);
+
+		expect(session.flushAction(true, d.dispatch)).toBe(true);
+		expect(d.sent).toEqual([{ kind: 'setReady', ready: true }]);
+		expect(session.state.heldAction).toBeNull();
+	});
+
+	it('keeps retrying a held action the server keeps refusing', () => {
+		const d = dispatcher(false);
+		const session = createRoomSession();
+
+		session.holdAction({ kind: 'startGame' });
+		expect(session.flushAction(true, d.dispatch)).toBe(false);
+		expect(session.flushAction(true, d.dispatch)).toBe(false);
+
+		expect(d.sent).toEqual([{ kind: 'startGame' }, { kind: 'startGame' }]);
+	});
+
+	it('replaces an unset held action with the player\'s later intent', () => {
+		// Readying, then leaving before either reaches the server: only the
+		// leave should still be waiting to go out.
+		const d = dispatcher();
+		const session = createRoomSession();
+
+		session.holdAction({ kind: 'setReady', ready: true });
+		session.holdAction({ kind: 'leaveRoom' });
+		session.flushAction(true, d.dispatch);
+
+		expect(d.sent).toEqual([{ kind: 'leaveRoom' }]);
+	});
+
+	it('drops a held action when the screen is torn down before it can be sent', () => {
+		const d = dispatcher();
+		const session = createRoomSession();
+
+		session.holdAction({ kind: 'cancelQueue' });
+		session.clearAction();
+
+		expect(session.flushAction(true, d.dispatch)).toBe(false);
+		expect(d.sent).toEqual([]);
+	});
+});