Description

EmbeddingSettings supports both embedder-level defaults and per-call overrides, merged via merge_embedding_settings(). Right now this behavior is only covered indirectly via higher-level tests. A small regression in the merge logic (for example changing from a shallow to a deep merge, or altering truthiness checks) could be hard to catch.

Proposed changes

Add focused unit tests for merge_embedding_settings() that cover:

• both inputs are None
• only base settings provided
• only override settings provided
• base and overrides provided, with overlapping and non-overlapping keys (per-call values win while other base keys are preserved)

These tests can live in tests/test_embeddings.py next to the other embedding tests and should not introduce any new external dependencies.