test(relay): behavioral coverage for request streaming, cancel, and error paths

[duyet]

Closes #23 (Plan 008).

Why

The relay streams local HTTP responses back over WebSocket as Head/Chunk/Done. Existing tests covered frame parsing and config only. A refactor could break forwarding, cancel, or UTF-8 splitting with green CI.

Scope

• src/relay.rs tests only. A loopback HTTP stub plus five handle_request tests.
  • streams_local_response_back_as_head_chunk_done
  • non_2xx_from_target_relays_status_and_body
  • unreachable_target_produces_error_frame
  • cancel_flag_stops_streaming
  • utf8_split_body_round_trips
• No production logic change. No new dependencies.
• Skipped the unused WebSocket FakeCloud from the issue. The five tests drive handle_request directly, which is the serving core.

Out of scope: tests/cli.rs, fixing production bugs (none found).

Tradeoffs

Cancel-before-call still POSTs, then returns after Head. The test allows Head and forbids Chunk/Done, matching the live handle_request loop.

Blast radius

Test-only. CI time grows by a loopback accept plus one 1 MiB stub body. No user-facing change.

Verification

• cargo test --locked --lib relay::tests — 19 passed, including the five new names
• Five consecutive reruns with --test-threads=1 — all passed
• cargo test --locked --all-targets — 186 lib + 68 cli + 7 release_lock passed
• git diff is +216 lines inside #[cfg(test)] only

Checklist

• Version stays on 0.1.x (do not introduce 0.2 / 1.0)
• Do not auto-merge release-please PRs

  

[github-actions]

anyr size and startup

Startup is wall time for a cold anyr --version / anyr --help (median of 21 runs). Size is the stripped release binary, or the .wasm for the browser demo.

Size budget: anyr-linux-x86_64 must stay ≤ 4.0 MiB (4194304 bytes) stripped.

Asset	Kind	Size	--version median	--help median
anyr-darwin-arm64	native	2.8 MiB	5.13 ms	3.72 ms
anyr-darwin-x86_64	native	3.0 MiB	42.44 ms	42.37 ms
anyr-linux-arm64	native	2.8 MiB	0.84 ms	0.84 ms
anyr-linux-x86_64	native	3.1 MiB	0.63 ms	0.62 ms
anyr-windows-x86_64.exe	native	2.5 MiB	9.79 ms	10.33 ms
anyr.wasm	wasm	176.5 KiB	—	—

Budget check: ok

raw timings

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