test: move TcpProxy to tests/tcp_proxy.py to fix collection

[dawmd]

tests/unit/test_tcp_proxy.py, added in d99dc46, imported its subject (TcpProxy) from tests/integration/standard/test_client_routes.py, which transitively imports tests/integration/init.py. That module guards its ccmlib imports with try/except ImportError, but then unconditionally declares class Cassandra41CCMCluster(CCMCluster) at module level, so on any environment without ccmlib installed the import fails with:

NameError: name 'CCMCluster' is not defined

This broke test collection consistently on the windows-2022 job, where ccmlib is absent. The latent defect in tests/integration/init.py predates d99dc46; that commit merely became the first unit test to import tests.integration and thus the first to expose it.

TcpProxy is a plain socket-based helper -- it depends only on socket, select and threading, and needs neither CCM nor a running Cassandra/Scylla cluster -- so it does not belong behind that import. Move it verbatim into a new tests/tcp_proxy.py and import it from both call sites:

• tests/integration/standard/test_client_routes.py now imports TcpProxy from tests.tcp_proxy; its select and socket imports, used only by the moved class, are dropped.
• tests/unit/test_tcp_proxy.py imports from tests.tcp_proxy and no longer needs its os.environ.setdefault("CASSANDRA_VERSION", ...) shim, which existed solely to get tests.integration's module-level version parsing to succeed. The shim and the docstring paragraph explaining it are removed.

The class body is byte-identical to the original; only the new module's license header, docstring and imports are new. No driver code is touched and no test behavior changes.

Validation:

• pytest tests/unit/test_tcp_proxy.py: 2 passed with neither CASSANDRA_VERSION nor SCYLLA_VERSION set, i.e. the unit test no longer imports tests.integration at all.
• tests/integration/standard/test_client_routes.py compiles clean with no imports left unused.

Fixes: #965

Pre-review checklist

• I have split my patch into logically separate commits.
• All commit messages clearly explain what they change and why.
• (N/A) I added relevant tests for new features and bug fixes.
• All commits compile, pass static checks and pass test.
• PR description sums up the changes and reasons why they should be introduced.
• (N/A) I have provided docstrings for the public items that I want to introduce.
• (N/A) I have adjusted the documentation in ./docs/source/.
• I added appropriate Fixes: annotations to PR description.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Reviewing files that changed from the base of the PR and between f634104 and f293f5a.

📒 Files selected for processing (3)

• tests/integration/standard/test_client_routes.py
• tests/tcp_proxy.py
• tests/unit/test_tcp_proxy.py

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📝 Walkthrough

Walkthrough

The TCP proxy moved to tests.tcp_proxy. The helper provides lifecycle control, backend retargeting, connection tracking, forced drops, bidirectional forwarding, and cleanup. Integration and unit tests now use the shared helper. The unit test no longer imports the integration module or sets CASSANDRA_VERSION.

Possibly related PRs

• scylladb/python-driver#949: Changes concurrency and teardown handling in the same TcpProxy implementation.
• scylladb/python-driver#963: Changes connection tracking during TcpProxy cleanup.

Suggested reviewers:mykaul

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: moving TcpProxy to tests/tcp_proxy.py to fix test collection.
Description check	✅ Passed	The description explains the cause, implementation, validation, scope, linked issue, and completed checklist items.
Linked Issues check	✅ Passed	The changes satisfy issue #965 by preventing unit tests from importing integration infrastructure without ccmlib.
Out of Scope Changes check	✅ Passed	The changes are limited to relocating the test helper, updating imports, and removing the obsolete environment workaround.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

---

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[Copilot]

Pull request overview

Moves TcpProxy into a dependency-free test helper module, preventing unit-test collection from importing CCM-dependent integration code and resolving issue #965.

Changes:

• Extracts TcpProxy into tests/tcp_proxy.py.
• Updates unit and integration tests to import the shared helper.
• Removes obsolete environment setup and unused imports.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tests/tcp_proxy.py	Adds the standalone TCP proxy helper.
tests/unit/test_tcp_proxy.py	Imports the helper without integration dependencies.
tests/integration/standard/test_client_routes.py	Uses the extracted helper and removes its former implementation.

---

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@tests/tcp_proxy.py`:
- Around line 88-91: Make retarget() update target_host and target_port while
holding _lock, and update _handle_new_connection() to capture both values under
the same lock before calling connect(). Release the lock before any connection
attempt so the snapshot is consistent without blocking connection establishment.
- Around line 72-80: Update _handle_new_connection so the backend
target_sock.connect attempt is bounded and observes shutdown state, rather than
blocking indefinitely on the listener thread. Ensure a shutdown can interrupt or
terminate the pending connection and that the socket is tracked or closed
consistently before stop() joins the listener and client connections. Apply the
same behavior to the corresponding connection path around the second referenced
location.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📒 Files selected for processing (3)

• tests/integration/standard/test_client_routes.py
• tests/tcp_proxy.py
• tests/unit/test_tcp_proxy.py

[dawmd]

The failure looks like #580:

Failure

===================================FAILURES===================================___________HostConnectionTests.test_successful_wait_for_connection____________self=<tests.unit.test_host_connection_pool.HostConnectionTeststestMethod=test_successful_wait_for_connection>deftest_successful_wait_for_connection(self):
host=Mock(spec=Host, address='ip1')
session=self.make_session()
conn=HashableMock(spec=Connection, in_flight=0, is_defunct=False, is_closed=False, max_request_id=100,
lock=Lock())
session.cluster.connection_factory.return_value=connpool=self.PoolImpl(host, HostDistance.LOCAL, session)
session.cluster.connection_factory.assert_called_once_with(host.endpoint, on_orphaned_stream_released=pool.on_orphaned_stream_released)
pool.borrow_connection(timeout=0.01)
assert1==conn.in_flightdefget_second_conn():
c, request_id=pool.borrow_connection(1.0)
assertconniscpool.return_connection(c)
t=Thread(target=get_second_conn)
t.start()
>pool.return_connection(conn)
/project/tests/unit/test_host_connection_pool.py:105: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ self=<cassandra.pool.HostConnectionobjectat0x000000004310d948>connection=<HashableMockname='mock.cluster.connection_factory()'spec='Connection'id='1125178344'>stream_was_orphaned=Falsedefreturn_connection(self, connection, stream_was_orphaned=False):
ifnotstream_was_orphaned:
withconnection.lock:
connection.in_flight-=1withself._stream_available_condition:
self._stream_available_condition.notify()
ifconnection.is_defunctorconnection.is_closed:
ifconnection.signaled_errorandnotself.shutdown_on_error:
returnis_down=Falseifnotconnection.signaled_error:
log.debug("Defunct or closed connection (%s) returned to pool, potentially ""marking host %s as down", id(connection), self.host)
is_down=self.host.signal_connection_failure(connection.last_error)
connection.signaled_error=Trueifself.shutdown_on_errorandnotis_down:
is_down=Trueifis_down:
self.shutdown()
self._session.cluster.on_down(self.host, is_host_addition=False)
else:
connection.close()
withself._lock:
ifself.is_shutdown:
returnself._connections.pop(connection.features.shard_id, None)
ifself._is_replacing:
returnself._is_replacing=Trueself._session.submit(self._replace, connection)>elifconnectioninself._trash:
^^^^^^^^^^^^^^^^^^^^^^^^^ETypeError: __hash__methodshouldreturnanintegernot'MagicMock'

[dawmd]

Sent an empty update to retrigger CI.

[dawmd]

@scylladb/python-driver-maint please consider merging