RSDK-13454: Replace loose_approx with expected_grpc_timeout in tests

[claude]

Summary

• Renamed loose_approx to expected_grpc_timeout across all 22 test files to clearly convey the function's intent
• Replaced relative tolerance (rel=1e-2) with absolute tolerance that models actual grpclib behavior:
  • >10s timeouts: abs=1.01s (~1s from encode_timeout integer-second truncation + ~10ms time_remaining jitter)
  • ≤10s timeouts: abs=0.011s (~1ms from encode_timeout integer-millisecond truncation + ~10ms time_remaining jitter)
• All existing tests pass without any changes to test values

DRI

@ale7714 is the responsible engineer for this PR.

Test plan

• All 371 affected tests pass (136 + 235 across both test runs)
• ruff format passes
• ruff check passes
• No remaining references to loose_approx in tests/

🤖 Generated with Claude Code

[ale7714]

I spend more time learning about this than I should have but the ticket has context https://viam.atlassian.net/browse/RSDK-13454

[claude]

Review: RSDK-13454 — Replace loose_approx with expected_grpc_timeout

Overall this is a solid, well-scoped rename. The new function name is self-documenting, the tolerance values are mathematically correct (verified against grpclib source), and the change is complete — no remaining loose_approx references anywhere in tests/.

Correctness — verified against grpclib source

grpclib.metadata.encode_timeout truncates (not rounds) via int():

timeout range	encoding	max truncation error
> 10s	integer seconds ('{}S')	< 1.0s
0.01–10s	integer milliseconds ('{}m')	< 0.001s

Adding ~10ms of time_remaining() jitter yields:

• abs=1.01 for val > 10 → 1.0 + 0.01 ✓
• abs=0.011 for val ≤ 10 → 0.001 + 0.010 ✓

The boundary val > 10 in expected_grpc_timeout exactly mirrors grpclib's own if timeout > 10 branch. No discrepancy.

Fix applied

tests/test_board.py line 367 contained a pre-existing debug print("timeout is", board.timeout) inside TestClient.test_set_power_mode. This was not introduced by this PR but was left in place. I removed it and pushed the fix directly.

No issues requiring changes-request

• All 22 test files updated; no stale references to loose_approx.
• src/viam/gen/ was not modified.
• No public API surface was changed.
• Format and lint pass cleanly.

[claude]

Code Review

What this PR does

Renames loose_approx → expected_grpc_timeout and replaces the vague 1% relative tolerance with tolerances grounded in grpclib's actual encode_timeout behaviour.

Correctness of the tolerance function

I verified the tolerance values against the real grpclib source (grpclib/metadata.py):

def encode_timeout(timeout: float) -> str:
    if timeout > 10:
        return '{}S'.format(int(timeout))   # integer-second truncation
    elif timeout > 0.01:
        return '{}m'.format(int(timeout * 10**3))  # integer-ms truncation
    ...

The threshold is exactly > 10, matching the PR's if val > 10 branch. The tolerance math is correct:

• >10s path (abs=1.01): int() truncation ≤ 0.999s + ~10ms jitter < 1.01s ✓
• ≤10s path (abs=0.011): int() truncation ≤ 0.999ms + ~10ms jitter < 11ms = 0.011s ✓

Issue fixed in this review

.github/workflows/update_protos.yml (not in PR, required workflow scope to push):
The AI prompt template on line 229 still referenced loose_approx(1.82). When the update-protos workflow runs, the agent would generate new test code calling the removed function, breaking those tests. I committed the fix locally but couldn't push it — the token is missing the workflow scope. This must be merged as a follow-up or the maintainer must push the one-line fix.

The local fix:

-   value1, timeout=loose_approx(1.82), extra={"a": "b"}, metadata={}
+   value1, timeout=expected_grpc_timeout(1.82), extra={"a": "b"}, metadata={}

Minor observation

The new abs=0.011 (11ms) is tighter than the old rel=1e-2 for all test values above 1.1s (e.g. 4.4s → old 44ms vs new 11ms). All 371 tests reportedly passed, and in-process ChannelFor channels incur negligible latency, so this is fine in practice — but worth noting if flakiness appears on a heavily loaded runner.

Everything else looks good

• Rename is complete across all 22 test files — no remaining loose_approx references in tests/
• src/viam/gen/ is not touched
• Debug print statement removed from test_board.py
• expected_grpc_timeout docstring accurately describes the encoding behaviour
• No new abstractions or scope creep