FIX: Avoid importing __future__ features during test collection

nibabel/__future__/conftest.py

@@ -0,0 +1,16 @@
+import pytest
+from packaging.version import Version
+from . import future_flags
+
+if Version(pytest.__version__) >= Version("7"):
+    def pytest_ignore_collect(collection_path):
+        if collection_path.name == "example_feature.py":
+            return True
+        if collection_path.stem in future_flags:
+            return True
+else:
+    def pytest_ignore_collect(path):
+        if path.basename == "example_feature.py":
+            return True
+        if path.basename[:-3] in future_flags:
+            return True