Run tests on all children images

tests/base-notebook/test_python.py

@@ -0,0 +1,25 @@
+# Copyright (c) Jupyter Development Team.
+# Distributed under the terms of the Modified BSD License.
+import logging
+
+from packaging import version  # type: ignore
+
+from conftest import TrackedContainer
+
+LOGGER = logging.getLogger(__name__)
+
+
+def test_python_version(
+    container: TrackedContainer, python_next_version: str = "3.10"
+) -> None:
+    """Check that python version is lower than the next version"""
+    LOGGER.info(f"Checking that python version is lower than {python_next_version}")
+    logs = container.run_and_wait(
+        timeout=5,
+        tty=True,
+        command=["start.sh", "python", "--version"],
+    )
+    actual_python_version = version.parse(logs.split()[1])
+    assert actual_python_version < version.parse(
+        python_next_version
+    ), f"Python version shall be lower than {python_next_version}"