From 85c40c3e25fd928897d5cfc4b253201bdc32d2ec Mon Sep 17 00:00:00 2001
From: davem-bis <68955845+davem-bis@users.noreply.github.com>
Date: Wed, 2 Sep 2026 13:55:56 +0100
Subject: [PATCH] Apply the isolated marker to all tests that utilise capsys.

Signed-off-by: davem-bis <68955845+davem-bis@users.noreply.github.com>
---
 tests/conftest.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 4d1bb23577..3d1928fba2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -216,8 +216,12 @@ def pytest_collection_modifyitems(items, *args, **kwargs):
             if marker.name in test_type_markers:
                 break
         else:
-            # if no test type marker is found, assume fast test
-            item.add_marker("fast")
+            # If no test type marker is found, assume it is a fast or isolated test.
+            if "capsys" in item.fixturenames:
+                # capsys is not threadsafe, so the test must be isolated.
+                item.add_marker("isolated")
+            else:
+                item.add_marker("fast")
 
 
 # Ignore all local config files