diff --git a/tests/calibration/conftest.py b/tests/calibration/conftest.py
new file mode 100644
index 000000000..5418a6599
--- /dev/null
+++ b/tests/calibration/conftest.py
@@ -0,0 +1,22 @@
+# SPDX-FileCopyrightText: 2026 John C. Travers and contributors
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+"""Fixtures for every calibration test."""
+
+from __future__ import annotations
+
+import pytest
+
+from solprop.calibration import _native
+
+
+@pytest.fixture(autouse=True)
+def _fresh_store_warnings(monkeypatch: pytest.MonkeyPatch) -> None:  # pyright: ignore[reportUnusedFunction]
+    """Give each test its own once-per-process store warnings.
+
+    The store and the profile reader warn once per message per process, so a test
+    expecting a warning would otherwise miss it after another test in its worker.
+    """
+    for module in (_native.profile, _native.store):
+        monkeypatch.setattr(module, "_WARNED", set())