Function getMessageWindow

tests/ui/chat/composerDockAnchoring.test.ts:16–22

(container: HTMLElement)

import { mockScrollMetrics as mockScrollportMetrics } from "../scrollMetrics";

function getMessageWindow(container: HTMLElement): HTMLDivElement {
  const element = container.querySelector('[data-testid="message-window"]');
  if (!element || element.tagName !== "DIV") {
    throw new Error("Message window not found");
  }
  return element as HTMLDivElement;
}

// These tests encode the structural contract behind the "send flash" + "hydration
// tear" fixes: