fix(tests): Resolve late binding of loop variable in assert message lambda

[ihb2032]

Purpose

This PR resolves a latent bug in the Mamba SSD tests identified by the Ruff linter (B023).
Ruff's B023 rule, which originates from flake8-bugbear, flagged an issue in the test_mamba_chunk_scan_cont_batch_prefill_chunking function. The msg parameter for torch.testing.assert_close was assigned a lambda function created inside a for loop. This lambda captured the loop variable i by reference, not by value, creating a "late binding" issue.
While this might not cause incorrect behavior with the current test runner, it posed a significant risk: if the test framework's behavior were to change to defer error message generation, any assertion failure would incorrectly report the final value of i, making debugging difficult and misleading.
This change corrects the variable capture by using a default argument in the lambda (lambda x, i=i: ...), which ensures the value of i is captured at definition time. This makes the test code more robust, eliminates the potential for misleading error messages, and allows for the removal of the # noqa: B023 suppressions.

Test Plan

Test Result

[gemini-code-assist]

Code Review

This pull request correctly resolves a late binding issue with a loop variable in lambda functions within the test suite, which improves the robustness and debuggability of the tests. The change is well-explained and follows Python best practices. However, the pull request also includes an unrelated file named hq that seems to be the output of a git command. This file should be removed before merging to keep the commit history clean.

[gemini-code-assist]

Code Review

This pull request correctly addresses a latent bug related to the late binding of a loop variable within lambda functions used for assertion messages in tests. By capturing the loop variable i by value using a default argument (i=i), the change ensures that assertion failure messages will be accurate and not misleading. This is a good practice and improves the robustness and debuggability of the tests. The implementation is clean and effectively resolves the issue identified by the Ruff linter (B023).

[DarkLight1337]

Thanks, let's merge #26247 first though

[DarkLight1337]

Please follow these steps to pass pre-commit now that we have changed the linter to ruff:

• Install ruff in in your local environment pip install ruff==0.11.7 (the same version used in CI)
• Run ruff format and commit the changes with --no-verify before merging main into your branch
• Now, when you merge main into your branch, any genuine conflicts will be much easier to handle

[DarkLight1337]

Please don't change vllm/third_party/pynvml.py

[DarkLight1337]

I'll override DCO this time