a Fake LLM that supports with_structured_output

[aviadr1]

Checked

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Feature request

I'd like to have a fake LLM for testing purposes that supports the with_structured_output method so that instead of testing "raw" output from LLM like with FakeListChatModel I could test returning a dict with either "parsed" or "parsing_error" or "raw" for testing the chain

Motivation

I am writing complex chains and want to write unit tests for them.
If I had a fake LLM that supports with_structured_output I could test the chain with fake outputs from an LLM and thus see what my chain does in various scenarios

Proposal (If applicable)

No response

[aabanic]

Any progress on this?