test: remove the races that make presence and push tests flaky - #705
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Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review. WalkthroughThe test updates synchronize realtime presence assertions, poll for server-timed events, and adjust annotation, authorization, and REST test behavior. The realtime test helper sets a default connection retry timeout. The HTTP request patch is restored when a wrapped test raises an exception. ChangesTest reliability updates
Estimated code review effort: 3 (Moderate) | ~20 minutes Suggested reviewers: Merge Risk: 🟡 Moderate · up to Push-test cleanup can leave records visible to later live-endpoint tests. Resolve or explicitly accept that test-reliability risk before merging. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
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In `@test/ably/rest/restpush_test.py`:
- Line 51: Update the fixture teardown around device_registrations.remove to
wait for asynchronous deletion completion: for every tracked device ID, poll
until the device registration list and its subscription list are both empty
before closing the client. Preserve the existing cleanup flow and ensure
teardown does not finish while records from the previous fixture remain.
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test/ably/realtime/realtimepresence_test.pytest/ably/rest/restpush_test.py
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ttypic
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Sep 23, 2026
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September 23, 2026 15:51
Six realtime presence tests subscribe to presence events and then have a second client enter, expecting to observe a live ENTER. An ATTACHED reply can carry the HAS_PRESENCE flag even for a brand-new empty channel, which opens a presence SYNC window. If the entering member is folded into that SYNC it arrives with action PRESENT, a 'present' event is emitted, and the live ENTER that follows carries the same message id, fails the RTP2b2 newness check and is discarded. Nothing is emitted and the test waits out its timeout. Discarding the duplicate is correct, so the tests are what needs to change: each now waits for the presence set to be in sync before the member enters. test_presence_auto_reentry_after_suspend slept for a fixed two seconds waiting for a server-driven LEAVE, which is long enough only when the runner is idle. It now waits for the events themselves. The push tests paired each device with a channel drawn from itertools.cycle during teardown, so a device the test body registered was matched against an arbitrary channel and its own registration was left behind. Removing a device registration also removes that device's channel subscriptions, so deleting every device covers both. Teardown still takes around ten seconds against a live endpoint, which leaves too little headroom under the 30s default per-phase timeout on a loaded runner, so the class carries a 120s timeout. Validated with a targeted thirty-iteration loop over the six presence tests: zero failures, against three in thirty on the same loop beforehand. The push file runs 44 passed, 0 failed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
…ures TestRestRequest published twenty messages from its setup fixture, so every test in the class paid for twenty sequential live POSTs, around three hundred per module. Only test_get reads them: it pages with a limit of ten and asserts on event0. test_post publishes its own message, test_error gets its 400 from an invalid limit whatever the channel holds, and the rest address /time, /not-found or a respx mock. Publishing from the one test that needs them takes the module from 322 live requests to 62, and each request is an independent chance to meet a stalled connection. That is what failed on 3.10: a single request sat in a TLS read for over thirty seconds and pytest-timeout killed the fixture. The SDK's http_request_timeout does not bound a request. httpx maps it to the read timeout, which httpcore applies to one socket read rather than to a whole response, and _receive_stream_event loops until the stream event arrives, so any frame on the connection starts the clock again. A read timeout that does fire then retries onto a fallback host, and the retry budget is only consulted once an attempt has already failed. That looseness is worth addressing on its own; fewer requests is the part that belongs here. The publishes now also run inside the test body, where assert_responses_type covers them. test_reauth_while_connecting asserted the RTC8b outcome without controlling which branch it reached. authorize() fetches a token over HTTPS before calling on_auth_updated, while the websocket handshake runs alongside it. Reaching on_auth_updated in CONNECTING halts the attempt, disposes the transport and starts a new one; reaching it in CONNECTED sends an AUTH message over the existing transport and deliberately keeps it, per RTC8a1. The test asserted the transport had changed, so whichever of the two won the race decided the result. Withholding protocol messages from the first transport holds the connection in CONNECTING for as long as the token fetch takes, which pins the RTC8b path. Forcing the losing interleaving with a two-second delay in the auth callback reproduces the CI assertion exactly, three times out of three, and the same forced delay passes three out of three with the test pinned. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
…s patch `restchannelhistory_test.py` was the only file in the suite to pass `fallback_hosts=[]`. `Options.get_fallback_hosts` returns that list verbatim because `[]` is not `None`, so the file ran against a single host and `should_stop_retrying` was true on the first iteration — any transport error reached the test. CI hit this as an HTTP/2 GOAWAY naming our own stream (`last_stream_id:1`), which httpcore will not retry because the server may have acted on the request. Using the endpoint's fallback hosts gives RSC15 a host to retry on; idempotent REST publishing is on by default and message ids are stamped before the request is sent, so the retried body is deduped by the server. `assert_responses_type` unpatched `Http.make_request` after the test body returned, so a test that raised left the patch in place for the rest of the process and the next test's patch wrapped it — visible in CI as a doubled `fake_make_request` frame. Unpatching in a `finally` keeps one failure from following later tests around. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
… tests The annotations test registered its `message` listener after publishing. `publish` resolves on the ACK and the channel emits every MESSAGE to listeners keyed only on `message.name`, with no action filtering, so whether the message's own create echo reached the listener depended on whether the ACK or the echo was processed first — about a millisecond apart. Winning that race resolved the future with a MESSAGE_CREATE and failed the assertion. The listener is now in place before the publish and selects the summary action, so the create echo is delivered and ignored rather than sometimes missed. Realtime tests allow five seconds to reach CONNECTED in ninety places, which is less than `realtime_request_timeout` and a third of `disconnected_retry_timeout`, so one failed connect attempt exhausted the budget waiting for the retry timer. `TestApp.get_ably_realtime` sets a short retry interval by default, which keeps those waits spanning several attempts; the tests that assert on retry timing pass their own value and are unaffected. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Based on #704, which has to land first for
checkto reach the test phase at all.Two unrelated sources of flakiness in the live-endpoint suite.
The presence SYNC race
Six tests in
realtimepresence_test.pyfollow the same shape: subscribe to presenceon one client, have a second client enter, assert the listener sees an
enter. Theyfail intermittently by timing out with no event at all.
From a wire trace: the server sets the
HAS_PRESENCEflag on theATTACHEDreplyeven for a brand-new, empty channel, which opens a presence SYNC window. When the
second client enters while that window is open, the member is folded into the SYNC
and arrives with
action: PRESENT— so apresentevent is emitted, not anenter.The live
ENTERthat follows carries the same message id, so_is_newerrejectsit,
PresenceMap.put()returnsFalse, and nothing is emitted for it.Suppressing the duplicate is the correct behaviour (RTP2d / RTP2g) and matches
ably-js, so the library is not at fault here — the tests are asserting on a live
event whose delivery they never arranged to be live. Each of the six now waits for
the presence set to be in sync (
await channel.presence.get()) before the memberenters, so anything that happens afterwards is observed as a live event.
test_presence_auto_reentry_after_suspendis a separate timing problem in the samefile: it slept a fixed two seconds waiting for a server-driven LEAVE gated on
remainPresentFor, which is long enough only on an idle runner. It now waits for theevents themselves.
The push teardown
restpush_test.py's teardown paired each device with a channel drawn fromitertools.cycle, so a device registered by the test body was matched against anarbitrary channel and its own registration was left behind — which matters, because
other tests in the file assert on the total number of registered devices. Removing a
device registration also removes that device's channel subscriptions, so deleting
every device covers both.
Teardown is around ten seconds of sequential requests against a live endpoint either
way; that is what exhausts the 30s default per-phase timeout on a loaded runner, so
the class now carries
@pytest.mark.timeout(120). The timeout marker is what makesthis file reliable, not the reduced request count.
Verification
realtimepresence_test.py, repeatedrestpush_test.pyAt a 10% per-run failure rate, 30 consecutive passes has probability ≈ 4%, so the
presence result is evidence rather than luck.
Not covered
A "missing LEAVE event" variant was reported alongside these but could not be
reproduced in 20 attempts, so nothing here is claimed to address it.
Two library bugs were found while tracing this and are filed separately — they do not
cause these failures, but they sit on the same path: a presence message whose id the
server omits gets a fabricated
"None:0"id, whichparse_id()then rejects with aValueErrorthat the transport only logs, silently dropping the message; andis_synthesized()returnsFalsefor an id-less message where RTP2b1 calls forTrue.Second commit: two more flakes, found by this PR's own CI
checkcame back green on 3.8, 3.9, 3.11, 3.13 and 3.14 and failed on 3.10 and 3.12,on two unrelated tests in files this PR had not touched.
TestRestRequestsetup timeout (3.10)ERROR at setup of TestRestRequest.test_error — Timeout (>30.0s), hung insidessl.readon an HTTP/2 stream read.
The setup fixture published twenty messages, so every test in the class paid for
twenty sequential live POSTs — around three hundred per module, each an independent
chance to meet a stalled connection.
test_errorwas not special; it drew the shortstraw. Only
test_getactually reads those messages (it pages withlimit=10andasserts on
event0);test_postpublishes its own,test_errorgets its 400 from aninvalid
limitwhatever the channel holds, and the rest address/time,/not-foundor a respx mock. Publishing from the one test that needs them takes the module from
322 live requests to 62, and the file from ~25.6s to ~14s.
The publishes now also run inside the test body, so
assert_responses_typecoversthem — it never did at fixture time.
Worth knowing separately:
http_request_timeoutdoes not bound anably.request()call. httpx maps it to the read timeout, which httpcore applies to a single socket
read rather than to a whole response, and
_receive_stream_eventloops until the streamevent arrives — so any frame on the connection restarts the clock. A read timeout that
does fire then retries onto a fallback host, and
should_stop_retryingconsults the15s budget only after an attempt has already failed. Measured against a local blackhole
server with instant connects: 20.0s for one
request().writeandpoolalsoresolve to
None, so a body write on a wedged connection blocks forever. That is aproduction change to RSC15 fallback semantics and wants its own PR — not this one.
test_reauth_while_connecting(3.12)assert connection_manager.transport is not original_transport— same object.The test asserted the RTC8b outcome without controlling which branch it reached.
authorize()fetches a token over HTTPS before callingon_auth_updated, while thewebsocket handshake runs alongside it. Reaching
on_auth_updatedinCONNECTINGhaltsthe attempt, disposes the transport and starts a new one (RTC8b); reaching it in
CONNECTEDsends anAUTHmessage over the existing transport and deliberately keepsit (RTC8a1, continuity). Whichever won the race decided the result.
The library is correct here — making it replace the transport on a
CONNECTEDreauthwould contradict RTC8a1 and break
test_reauth_while_connectedandtest_capability_change_without_loss_of_continuity. Withholding protocol messages fromthe first transport holds the connection in
CONNECTINGfor as long as the token fetchtakes, which pins the RTC8b path.
Verification of the second commit
restrequest_test.py+ sync counterpart, 5 runsrealtimeauth_test.pyfull file, 3 runsruff check ably/ test/Neither flake was reproduced naturally — the reauth test was 30/30 green unforced, and
the
restrequesthang never recurred. The evidence for the reauth fix is the forced-delaypair above, which isolates the logic rather than the timing. The evidence for the
restrequestchange is the 81% cut in exposure, not a reproduction.Third commit: the GOAWAY flake, and a patch leak found alongside it
checkcame back green on 3.8, 3.9, 3.11, 3.12, 3.13 and 3.14 — the reauth fix aboveholds — and failed on 3.10 with two failures that are the same failure:
The history tests ran with retries disabled
restchannelhistory_test.pywas the only file in the suite to passfallback_hosts=[].Options.get_fallback_hostsreturns that list verbatim because[]is notNone, so__get_hostsbuilt[host] + []— one host — andshould_stop_retrying()was true oniteration 0. Every other file in the suite gets three hosts from the endpoint and has a
transport error retried out from under it. That is why both failures were in this one
file, and why they were in a file this PR had not touched.
The
fallback_hosts=[]arrived in 5966631 ("use 'sandbox' environment instead of explicithosts", Mar 2023) as an incidental part of an endpoint migration. It asserts nothing.
The GOAWAY itself is not the classic stale-keepalive race. httpcore retries a
ConnectionTerminatedonly when our stream id is strictly greater than the GOAWAY'slast_stream_id— "the server never touched this request". CI showslast_stream_id:1and the error propagated, so our stream was stream 1: a brand-new connection, GOAWAY'd
on its first request, which RFC 7540 §6.8 makes genuinely ambiguous.
http2=False, ashorter
keepalive_expiryor a connection-lifetime cap would not have prevented this,which is worth stating because those are the obvious first guesses.
Idempotent REST publishing is on by default (
api_version = '5') and message ids arestamped in
Channel.__publish_request_bodybefore the request is sent, so a retriedbody carries the same ids and the server can dedupe it.
test_idempotent_library_generated_retry(RSL1k4) asserts this for a retry against thesame host.
That dedupe is not unconditional, and the commit message for this change overstates
it. Probing the live sandbox with the same message id twice: same host 0/5 duplicated,
primary → fallback 0/20, but fallback → fallback 4/15 duplicated (pairs
a+e,c+e,d+e,a+b), givinghistory=2. Dedupe appears to be per-region. RSC15f pins a fallbackhost for ten minutes after a successful retry, so a second transport error inside these
tests would be a fallback → fallback retry — and these tests assert exact counts
(
assert len(messages) == 50, lines 67 and 82).So this change trades "any transport error fails the test" for "a second transport error
may add a 51st message". That is a strictly smaller exposure — one failure is survived
outright, and a duplicate needs two failures in one test — but it is not zero, and it is
not the clean guarantee the commit message claims. Whether cross-region dedupe is meant
to work is worth a question to the realtime team; if it is, the 4/15 result is a platform
defect rather than a test concern. Caveat on that number: 15 trials from one network
vantage point, and the resolved region of each host was not confirmed.
Not fixed by this: any single-host configuration still hard-fails on the first transport
error, which affects every customer using an explicit rest host. See below.
A failing test used to leak its monkeypatch
The CI traceback contains a doubled frame:
assert_responses_typeunpatchedHttp.make_requestafter the test body returned ratherthan in a
finally, so a test that raised left the patch installed for the rest of theprocess and the next test's patch wrapped it. Measured directly, forcing a decorated test
to raise:
test/ably/utils.pyHttp.make_request still patchedThis fixes no flake by itself. It stops one failure following later tests around, and it
makes tracebacks readable.
Verification of the third commit
restchannelhistory_test.py+ sync counterpart, 3 runsrestcrypto+restchannelpublish, async + syncfallback_hosts=[]RemoteProtocolError, matching CIGOAWAY(NO_ERROR, last_stream_id=1), single hostruff check ably/ test/This flake was not reproduced naturally: 12/12 unmodified runs against the live
sandbox passed. The green runs above are not evidence on their own — the evidence is the
injected control pairs, where the two arms differ only by the line in the diff.
Also diagnosed, deliberately not fixed here
40105 401 Nonce value replayedfailsrestcapability_test.pyandrestauth_test.pyintermittently across branches and Python versions. It is the same defect seen from the
other side:
make_requestserialises the body once, before the host loop, and re-sendsthose exact bytes to the next host — same nonce, same timestamp, same MAC. A GOAWAY on
the last host surfaces as
RemoteProtocolError; a GOAWAY on an earlier host isretried, and for a token request the server rejects the replayed nonce. Confirmed with a
fake sandbox that consumes a nonce and drops the first response: unmodified → 2 attempts,
1 distinct nonce,
40105; re-signing per attempt → 2 distinct nonces, success.The only test-side lever is
http_max_retry_count=1, which converts the40105back intoa
RemoteProtocolErrorand weakens coverage. So it is not fixed here.That leaves three findings for a production PR on
make_request, all retry semantics:http_request_timeoutdoes not bound a request (detailed above).🤖 Generated with Claude Code
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