diff --git a/testapp/templates/show-cookie-bar-script.html b/testapp/templates/show-cookie-bar-script.html
index 269edf8..caaba5f 100644
--- a/testapp/templates/show-cookie-bar-script.html
+++ b/testapp/templates/show-cookie-bar-script.html
@@ -21,6 +21,8 @@
       },
       onDecline: () => document.querySelector('body').classList.remove('with-cookie-bar'),
     });
+
+    document.getElementById('loading-marker').style.display = 'inline';
 </script>
 
 <template id="show-share-button">
diff --git a/testapp/templates/test_page.html b/testapp/templates/test_page.html
index e57e3ac..ac6757c 100644
--- a/testapp/templates/test_page.html
+++ b/testapp/templates/test_page.html
@@ -10,6 +10,8 @@
   <body>
     <h1>Test page</h1>
 
+    <span id="loading-marker" style="display:none">page-done-loading</span>
+
     <h2>Social cookies</h2>
     <p>
         sharing button is displayed below only if "Social" cookies are accepted.
diff --git a/tests/test_javascript_cookiebar.py b/tests/test_javascript_cookiebar.py
index 0b51fb5..5875e9a 100644
--- a/tests/test_javascript_cookiebar.py
+++ b/tests/test_javascript_cookiebar.py
@@ -22,6 +22,8 @@
 def before_each_after_each(live_server, page: Page, load_testapp_fixture):
     test_page_url = f"{live_server.url}{reverse('test_page')}"
     page.goto(test_page_url)
+    marker = page.get_by_text("page-done-loading")
+    expect(marker).to_be_visible()
     yield
 
 
@@ -72,6 +74,8 @@ def test_on_accept_handler_runs_on_load(page: Page, live_server):
 
     test_page_url = f"{live_server.url}{reverse('test_page')}"
     page.goto(test_page_url)
+    marker = page.get_by_text("page-done-loading")
+    expect(marker).to_be_visible()
 
     share_button = page.get_by_role("button", name="SHARE")
     expect(share_button).to_be_visible()
