diff --git a/plinth/tests/functional/__init__.py b/plinth/tests/functional/__init__.py
index 6ff531143..578d7593a 100644
--- a/plinth/tests/functional/__init__.py
+++ b/plinth/tests/functional/__init__.py
@@ -835,13 +835,13 @@ class BaseAppTests:
         submit(session_browser, form_class='form-diagnostics-button')
 
         warning_results = session_browser.find_by_css(
-            '.diagnostic-result > .text-bg-warning')
+            '.diagnostics-result > .text-bg-warning')
         if warning_results:
             warnings.warn(
                 f'Diagnostics warnings for {self.app_name}: {warning_results}')
 
         failure_results = session_browser.find_by_css(
-            '.diagnostic-result > .text-bg-danger')
+            '.diagnostics-result > .text-bg-danger')
         assert not failure_results
 
     @pytest.mark.backups