test: fix flaky CanRestartStream test on .NET Framework#123
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…ramework On .NET Framework 4.6.2, cancelling a stream read can surface as an IOException rather than OperationCanceledException. This causes an Error event to fire before the Closed event during restart, which is a race condition that makes the test flaky. Add an allowSkip predicate overload to EventSink.ExpectActions that deterministically drains matching events from the blocking queue rather than using delays or timeouts. The CanRestartStream test uses this to skip Error events that are an expected side effect of cancellation on .NET Framework. Co-Authored-By: rlamb@launchdarkly.com <4955475+kinyoklion@users.noreply.github.com>
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tanderson-ld
approved these changes
Jul 1, 2026
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Summary
CanRestartStream(resetBackoff: False)flakes on net462 becauseRestart()cancels an in-flight HTTP request, and on .NET Framework the cancellation surfaces as anIOException(notOperationCanceledException). This causesEventSourceto fire anErrorevent beforeClosed, but the test only expectedClosed → Opened → MessageReceived.The fix adds a deterministic
allowSkippredicate overload toEventSink.ExpectActions:When waiting for the next expected action, any action matching
allowSkipis consumed from theBlockingCollectionand discarded — no sleeps or arbitrary timeouts. TheCanRestartStreamtest usesa => a.Kind == \"Error\"to skip the platform-specific cancellation error events after each restart.Link to Devin session: https://app.devin.ai/sessions/d88b0648af0f43babf666a735ae65524
Requested by: @kinyoklion
Note
Low Risk
Test-helper and test-only changes with no production EventSource behavior modified.
Overview
Stabilizes
CanRestartStreamon .NET Framework by tolerating extraErrorevents that can appear whenRestart()cancels an in-flight read and cancellation shows up asIOExceptioninstead ofOperationCanceledException.EventSink.ExpectActionsgains an optionalallowSkippredicate: while matching the expected sequence, any received action that satisfies the predicate is taken from the queue and ignored (no sleeps). The parameterless overload forwards toallowSkip: null. The restart loop usesa => a.Kind == "Error"so only the platform-specific cancellation errors are skipped;Closed→Opened→MessageReceivedassertions stay the same.Reviewed by Cursor Bugbot for commit 5c44e2b. Bugbot is set up for automated code reviews on this repo. Configure here.