test: fix flaky macOS aiohttp connection refusal test

[masenf]

The macOS unit job on main fails because test_connection_refused assumes a bound, non-listening socket immediately refuses connections. On the runner it instead produces a connection timeout, so the timed_out=False assertion fails. See the failing job.

Move connection-refusal coverage into the existing parameterized error-mapping test by injecting an aiohttp ClientConnectorError wrapping ECONNREFUSED. Preserve the sent=False and timed_out=False assertions and verify exception chaining for every error case. This changes only tests.

Validation:

• Build SDK unit suite: 768 passed.
• Full unit suite: 11,234 passed, 159 skipped, and 18 unrelated JavaScript failures with the shell's Node 18. All 18 failures passed when rerun with CI's Node 22 (19 tests passed in that rerun).
• Full-run coverage: 79%.
• Repository-wide Ruff lint and formatting checks passed.
• uv run pyright reflex tests: zero errors or warnings.
• Adversarial review: no actionable findings.

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}

[greptile-apps]

Confidence Score: 5/5

[Low risk] Test fix for flaky macOS connection refusal behavior.

The PR appears safe to merge; no actionable issue was established.

Summary

Replaces a platform-dependent connection-refusal test with a parameterized, injected aiohttp error case.

• Preserves the refusal mapping assertions and checks exception chaining across the error cases.

_{Reviews (1) · Last reviewed commit: "test: make aiohttp connection refusal co..."}

[codspeed]

Merging this PR will not alter performance

✅ 150 untouched benchmarks
⏩ 18 skipped benchmarks¹

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_{Comparing codex/fix-macos-connection-refused-test (632b797) with main (eb14860)}

Footnotes

1. 18 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩