Adds two boundary tests suggested by code review:
- TestBuildProviderRequest_CachingEnabled_EmptyMessages: verifies
that caching with an empty message list still emits a CacheHints
with LastCacheableMessageIndex=-1, not a spurious breakpoint.
- TestBuildProviderRequest_CachingNonNilButDisabled: verifies that
an explicitly-disabled cacheConfig (non-nil, enabled=false)
produces nil CacheHints, exercising the &&-guard branch that
the previous "disabled" test left untested.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
buildProviderRequest now computes cache-breakpoint positions automatically
when the WithPromptCaching() option is set. It places up to 3 hints:
tools, system, and the index of the last non-system message. Providers
that don't support caching (OpenAI, Google) ignore the field.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Introduces an opt-in RequestOption that callers can pass to enable
automatic prompt-caching markers. The option populates a cacheConfig
on requestConfig but has no effect yet — plumbing through to
provider.Request and on to the Anthropic provider lands in subsequent
commits.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Cover all core library logic (Client, Model, Chat, middleware, streaming,
message conversion, request building) using a configurable mock provider
that avoids real API calls. ~50 tests across 7 files.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
