Add Ollama client tests

[ElyssaN]

No description provided.

[AJaccP]

Test behaviour looks correct! One code style suggestion:

The mock_async_client helper currently uses patcher.start() and every test needs its own try/finally: patcher.stop() to clean up. If you make the helper a @contextmanager, cleanup becomes automatic and the per-test boilerplate goes away. The response/client setup at the top is unchanged — only the patcher.start() lines and the return change:

• Add from contextlib import contextmanager at the top
• Add @contextmanager above the helper definition
• Setup stays the same up to client.post = AsyncMock(return_value=response). After that, replace:

patcher = patch("src.infrastructure.llm.httpx.AsyncClient")
mocked_async_client_cls = patcher.start()

with

with patch("src.infrastructure.llm.httpx.AsyncClient") as mocked_async_client_cls:

and put the rest of the lines indented inside the with block

• The final return would just become yield client, response

Then each test can drop the patcher, client, _ = ... and try/finally lines and just have something like:

with mock_async_client(json_data={"embedding": fake_embedding}) as (client, _):
    <test code...>

If a test doesn't use client/response (like the one on line 64 currently), you can drop the as (client, _) entirely and just write with mock_async_client(...):

These changes help trim some boilerplate code in the tests and help prevent a hypothetical future test from forgetting the stop() for cleanup.