The first pass accepted any empty completion whose finish_reason was "length",
which also swallowed a fallback that produced nothing at all. Require the
response to have billed completion tokens as well, so empty content is
accepted only when the budget was demonstrably spent on non-visible reasoning.
Asserts on completion_tokens rather than reasoning_tokens because the latter
is provider-optional; with empty content and a refusal of null, consumed
completion tokens are reasoning by elimination, since visible text would be
content. Both counts are reported in the failure message.
Folds the three body accessors onto one _parsed helper instead of re-parsing
per call, and adds completion_tokens_of / reasoning_tokens_of alongside.
max_tokens=64 caps reasoning plus visible output on gpt-5.5, so the fallback
target can legitimately return finish_reason="length" with empty content.
litellm-e2e build 90 hit exactly that: the response cost of $0.002005 backs
out to 64 completion tokens at gpt-5.5's $3e-05/token, i.e. the whole budget
spent reasoning about "say hi" with none left to answer. The fallback itself
worked -- 200, served by gpt-5.5-2026-04-23, x-litellm-attempted-fallbacks
present -- so the only thing that failed was an assertion about OpenAI's token
budgeting rather than about routing.
Raise the reliability helper's budget to 512 and accept empty content only
when finish_reason is "length". Empty content under any other finish_reason
still fails, so the tests keep catching a fallback that returns nothing for a
reason we do control.
The relaxed assertion lives in the helper both reliability fallback tests
share, so test_timeout_routes_to_fallback is covered too; it has the same
shape and had not tripped yet.
The mid-conversation system tests prime the prompt cache by re-sending an
identical /v1/messages body until its usage shows the full prefix read back
three times in a row. The e2e stack runs with the litellm response cache on,
so every resend after the first is served from redis with the first call's
usage and the streak can never form; the three unflagged-model tests have
failed on every litellm-e2e build since the consecutive-read check landed.
Send cache: {"no-cache": true} on RichMessagesRequest, as test_cache_control
already does, so each resend reaches the provider.
The two fallback tests sent the same "say hi" / max_tokens=16 body to the
gpt-5.5 fallback, so one empty (finish_reason=length) completion served the
second test from the response cache and failed both. Give each test a unique
prompt and leave gpt-5.5 enough tokens to emit text.
* test(e2e): add reliability suite covering fallback, timeout, and cache behavior
* test(e2e): move reliability suite under router and drive it with real deployments
* test(e2e): make the router complexity fixture opt-in so reliability tests can coexist
