fix(engine): replace fixed sleeps with polling in backpressure tests#370
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streamer45 merged 1 commit intomainfrom Apr 25, 2026
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The test_dynamic_connection_under_backpressure test used a fixed 100ms sleep before asserting the pacer node reached Running state. On slow CI runners the node lifecycle (Creating → Initializing → Running) takes longer than 100ms, causing sporadic assertion failures. Replace all fixed sleep + assert patterns across the three backpressure tests with a wait_for_states polling helper (same pattern used in the async_node_creation test suite). Each call polls get_node_states() every 20ms with a 5-second timeout, eliminating timing-dependent flakiness. Signed-off-by: StreamKit Devin <devin@streamkit.dev> Co-Authored-By: Claudio Costa <cstcld91@gmail.com>
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Summary
The
test_dynamic_connection_under_backpressuretest uses a fixed 100ms sleep before asserting the pacer node reachedRunningstate. On slow CI runners (e.g. this run) the node lifecycle (Creating → Initializing → Running) takes ~206ms, causing the assertion to fire before the node is ready.This PR replaces all fixed
sleep+ assert patterns across all three backpressure tests with await_for_statespolling helper — the same pattern already used in theasync_node_creationtest suite (crates/engine/src/tests/async_node_creation.rs:252). Each call pollsget_node_states()every 20ms with a 5-second timeout, eliminating timing-dependent flakiness.Changes:
wait_for_statespolling helper tobackpressure.rstest_backpressure_no_deadlock: replace 500ms sleep + two separate asserts with a single poll for bothreaderandpacerstatestest_dynamic_connection_under_backpressure: replace 100ms sleep + assert with poll forpacer=Runningtest_node_removal_under_backpressure: replace 100ms sleep with poll for pacer to leaveCreatingstate before removalReview & Testing Checklist for Human
wait_for_stateshelper matches the established pattern inasync_node_creation.rs(same poll interval, same signature)cargo test -p streamkit-engine --test backpressurelocally to confirm all 3 tests passNotes
The root cause was visible in the CI logs — the pacer's
Runningstate update arrived at11:53:31.158672Z, but the 100ms sleep (started aftersend_controlreturned at ~11:53:30.952Z) expired at ~11:53:31.052Z— about 107ms too early.Link to Devin session: https://staging.itsdev.in/sessions/8a81ffd549e742f8a209ff82586c27f6
Requested by: @streamer45