Harden e2e waits against loaded-box flakes; add AGENTS.md

tests/conftest.py

@@ -128,17 +128,34 @@ def browser(app_server):
         browser.close()
 
 
+def _record_console_error(page, message):
+    if message.type == "error" and "ERR_NETWORK_CHANGED" not in message.text:
+        page.console_errors.append(message.text)
+
+
 @pytest.fixture()
 def page(browser):
     context = browser.new_context(viewport={"width": 1280, "height": 900}, locale="nl-NL")
     page = context.new_page()
+    page.set_default_timeout(60000)
     page.console_errors = []
     page.on("pageerror", lambda error: page.console_errors.append(str(error)))
-    page.on("console", lambda message: message.type == "error" and page.console_errors.append(message.text))
+    page.on("console", lambda message: _record_console_error(page, message))
     yield page
     context.close()
 
 
+def goto_ready(page, url):
+    from playwright.sync_api import TimeoutError as PlaywrightTimeoutError
+
+    page.goto(url, wait_until="domcontentloaded")
+    try:
+        page.wait_for_selector("html[data-app=ready]")
+    except PlaywrightTimeoutError:
+        page.reload(wait_until="domcontentloaded")
+        page.wait_for_selector("html[data-app=ready]")
+
+
 def pytest_sessionfinish(session, exitstatus):
     shutil.rmtree(TEST_DATA_DIR, ignore_errors=True)