headroom/tests/test_proxy
Abhay Singh b97c7c6e99
fix(proxy/gemini): keep streaming-parity baseline so eligible_pct can't exceed 100 (#2824)
## Description

The non-streaming Gemini `generateContent` finalizer builds its
`RequestOutcome` with `optimized_tokens` set to Gemini's own
`promptTokenCount` (the provider's tokenizer scale, which correctly
feeds billing and the dashboard), while `original_tokens` stays a local
estimator count. Those two are on different rulers.

Every delta the beacon derives from the pair is a same-ruler difference:
`tokens_saved`, `tokens_inflated`, `attempted_input_tokens`, and the
beacon's `eligible_pct` / `yield_pct`. When Gemini counts the forwarded
prompt higher than our local estimator does, `attempted_input_tokens`
(which is `optimized_tokens + tokens_saved`) exceeds the local
`original_tokens`, and the request ships a structurally-impossible
`eligible_pct > 100` plus a phantom `tokens_inflated`. This is the exact
class of bug #2756 removed, on a path #2756 did not touch: it fixed the
non-streaming OpenAI handler, and the streaming finalizer
(`_finalize_stream_response`) already guards against it by lifting the
baseline onto the provider scale. The non-streaming Gemini path had
neither treatment.

The fix mirrors the streaming finalizer's already-tested handling: when
a provider count is present, lift the baseline to `max(original_tokens,
promptTokenCount + tokens_saved)` so `attempted_input_tokens <=
original_tokens` holds and `tokens_inflated` collapses to 0. It is
guarded on a present count, so a null or absent `promptTokenCount`
leaves the local baseline untouched and the existing zero-usage
preservation test still holds. `optimized_tokens` still carries the
provider count, so billing and the dashboard are unchanged.

Closes #

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)

## Changes Made

- `headroom/proxy/handlers/gemini.py` (`handle_gemini_request`,
non-streaming `generateContent` branch): compute
`effective_original_tokens = max(original_tokens, total_input_tokens +
tokens_saved)` when `total_input_tokens > 0` (else keep
`original_tokens`), and pass it as the outcome's `original_tokens`.
Mirrors the streaming finalizer's provider-usage handling.
- `tests/test_proxy/test_gemini_savings_profile.py`: added
`test_gemini_provider_count_above_local_estimate_does_not_inflate_eligible`,
which drives a request where Gemini's `promptTokenCount` (150) exceeds
the local post-compression count (80), and asserts
`attempted_input_tokens <= original_tokens`, `tokens_inflated == 0`, the
provider count is still carried in `optimized_tokens`, and the baseline
is lifted to 170.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [x] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [ ] Manual testing performed

### Test Output

```text
# Fail-before (source fix stashed, new test kept):
tests/test_proxy/test_gemini_savings_profile.py::test_gemini_provider_count_above_local_estimate_does_not_inflate_eligible FAILED
  assert outcome.attempted_input_tokens <= outcome.original_tokens
  AssertionError: assert 170 <= 100

# Pass-after (fix applied):
tests/test_proxy/test_gemini_savings_profile.py::test_gemini_provider_count_above_local_estimate_does_not_inflate_eligible PASSED

# Full file + related outcome suites:
tests/test_proxy/test_gemini_savings_profile.py tests/test_proxy_gemini_native_integration.py tests/test_request_outcome.py tests/test_outcome_token_scale.py
47 passed, 18 skipped

# uvx ruff@0.15.17 check  -> All checks passed!
# uvx mypy@1.20.2 headroom/proxy/handlers/gemini.py -> Success: no issues found in 1 source file
```

## Real Behavior Proof

- Environment: Windows 11, Python 3.12.11, project venv (litellm
installed), pytest 9.1.1 with pytest-asyncio 1.4.0 (asyncio_mode=auto
per pyproject), ruff 0.15.17 and mypy 1.20.2 via uvx.
- Exact command / steps: confirmed the streaming sibling already lifts
the baseline (`_finalize_stream_response` in
`headroom/proxy/handlers/streaming.py` sets `effective_original_tokens =
max(original_tokens, provider_input_tokens + tokens_saved)` for
openai/gemini), then fail-before with `git stash push
headroom/proxy/handlers/gemini.py` and `python -m pytest
tests/test_proxy/test_gemini_savings_profile.py -k inflate_eligible`
(the assertion fails with `170 <= 100`, i.e. eligible_pct 170%), then
pass-after with `git stash pop` and rerunning (passes), then the full
file plus the outcome suites (47 passed, 18 skipped).
- Observed result: with Gemini reporting `promptTokenCount=150` against
a local post-compression count of 80 (saved 20), the outcome now reports
`original_tokens=170`, `attempted_input_tokens=170` (so `eligible_pct <=
100`) and `tokens_inflated=0`, while `optimized_tokens` stays 150 so
billing and the dashboard are unchanged. Before the fix the same request
reported `original_tokens=100`, `attempted_input_tokens=170`
(eligible_pct 170%) and `tokens_inflated=50`.
- Not tested: a live streamed call to real Gemini/Vertex (no provider
credentials in this environment). The provider-count-above-local case is
reproduced with a mock response mirroring Gemini's `usageMetadata`
shape, and the baseline-lift it mirrors is existing, tested code on the
streaming path.

## Review Readiness

- [x] I have performed a self-review
- [x] This PR is ready for human review

## Checklist

- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] I did **not** edit `CHANGELOG.md`: it is generated by
release-please from my Conventional Commit PR title (a CI guard enforces
this)

## Additional Notes

Docs and manual testing are N/A: this aligns the non-streaming Gemini
finalizer with the already-correct streaming finalizer, no API surface
change. The baseline lift is guarded on a present provider count, so the
existing zero-usage preservation test
(`test_gemini_zero_usage_prompt_count_is_preserved`) is unaffected: a
null or zero `promptTokenCount` keeps the local baseline and leaves
`optimized_tokens` at 0.
2026-08-06 19:21:56 -07:00
..
test_anthropic_buffered_timeout.py fix(proxy): add an Anthropic buffered read-timeout override (#1331) 2026-06-23 22:46:31 -05:00
test_anthropic_ccr_deferred_injection.py fix(proxy): stop toggling headroom_retrieve in the Anthropic tools array (#2672) 2026-08-03 16:18:11 -07:00
test_anthropic_ccr_raise.py fix(anthropic): CCR exception must re-raise, not silently swallow (#838) 2026-06-10 21:11:46 -05:00
test_anthropic_streaming_ccr_retrieve.py fix(proxy): keep buffered CCR streams alive (#2479) 2026-07-22 06:09:05 -07:00
test_anthropic_upstream_header.py fix(proxy): honor x-headroom-base-url on /v1/messages route (#1763) 2026-07-09 12:43:40 -05:00
test_background_compression.py perf(compression): take large cold-start contexts off the synchronous kompress path (#1171) (#1298) 2026-06-23 10:48:06 -05:00
test_bedrock_passthrough.py feat(proxy): compress AWS Bedrock InvokeModel requests via configurable upstream (#720) 2026-06-16 14:56:16 -05:00
test_bedrock_sse_ping.py fix: emit SSE ping before message_start on Bedrock streaming path (issue #902) (#1080) 2026-08-04 21:41:58 -05:00
test_cc_switch_reconciler.py feat(proxy): cc-switch reconciler — keep Headroom in the request path alongside cc-switch (#1030) 2026-06-17 08:41:16 -05:00
test_ccr_frozen_prefix_coupling.py fix(proxy): stop toggling headroom_retrieve in the Anthropic tools array (#2672) 2026-08-03 16:18:11 -07:00
test_compression_failure_action.py fix(codex): fail open for proxy compression timeout 2026-06-04 14:04:49 +05:30
test_compression_timeout_config.py feat(proxy): make COMPRESSION_TIMEOUT_SECONDS configurable via env (#946) (#991) 2026-06-16 21:10:01 -05:00
test_compute_turn_id.py fix(proxy): strip cache_control before hashing turn_id 2026-04-23 16:04:57 +02:00
test_gemini_savings_profile.py fix(proxy/gemini): keep streaming-parity baseline so eligible_pct can't exceed 100 (#2824) 2026-08-06 19:21:56 -07:00
test_header_safe_transforms.py feat(transforms): attribute read_lifecycle + smart_crush tags (#249) 2026-06-11 11:51:26 -05:00
test_mcp_stats_aggregation.py fix(proxy): Strands MCP bundle + backend path fixes + Codex fail-closed protection 2026-05-21 11:00:14 -07:00
test_model_router.py feat(proxy): add opt-in cost-aware model router (#1706) (#2205) 2026-07-15 19:58:17 +00:00
test_model_router_wiring.py feat(proxy): add opt-in cost-aware model router (#1706) (#2205) 2026-07-15 19:58:17 +00:00
test_openai_backend_path.py fix(proxy): skip max_tokens rename for backend-routed openai chat (#2401) 2026-07-18 16:47:10 -07:00
test_openai_chat_savings_profile.py fix(proxy/openai): None-guard usage token counts on the chat path (#2431) 2026-07-19 22:15:22 -07:00
test_openai_responses_ccr.py fix(proxy): keep buffered CCR streams alive (#2479) 2026-07-22 06:09:05 -07:00
test_openai_stream_usage_option.py fix(proxy/openai): respect explicit stream_options.include_usage (#2026) 2026-07-13 00:43:16 -04:00
test_openai_transport_path_prefix.py fix(codex): OpenCode Zen telemetry attribution (#1648) 2026-07-07 11:35:21 -05:00
test_openai_upstream_header.py fix(proxy): preserve sub-path in X-Headroom-Base-Url custom upstream (#2037) (#2127) 2026-07-13 19:53:45 -04:00
test_phase3_byte_identity.py perf(compression): take large cold-start contexts off the synchronous kompress path (#1171) (#1298) 2026-06-23 10:48:06 -05:00
test_request_logger.py feat(proxy): log compressed messages alongside original request (#261) 2026-06-11 19:02:54 -05:00
test_settings_fresh_process_precedence.py fix(proxy): dedupe Codex WS request logging for accurate mixed-provider dashboards (#2189) 2026-07-15 18:18:34 +00:00
test_settings_store.py fix(proxy): dedupe Codex WS request logging for accurate mixed-provider dashboards (#2189) 2026-07-15 18:18:34 +00:00
test_transformations_feed.py fix(proxy): scope CORS to loopback + gate operator/content endpoints (#1226) 2026-06-21 00:50:55 -07:00