litellm - 💡(How to fix) Fix [Compat Matrix] Slice 6: Unit tests for Claude Code CLI Driver [1 participants]

Parent PRD

#26476

What to build

Add unit tests for the Claude Code CLI Driver module introduced in slice #26477. Per the PRD's "Testing Decisions" section, the driver is a deep module wrapping a fast-moving external dependency, and high-value coverage comes from mocked-subprocess unit tests that exercise the driver's external behavior.

The tests feed canned claude stream-JSON output (and various error conditions) to the driver via a mocked subprocess and assert the driver's structured result, error handling, and argument assembly. Tests should exercise external behavior only — the contract of the driver's entry-point function — not internal helpers. Prior art: the LiteLLM repo's tests/test_litellm/ contains many tests using this exact mocked-external-dependency pattern.

This slice can be pursued in parallel with slices #26478, #26479, #26480, and #26481 once #26477 has merged.

Acceptance criteria

• Unit tests for the Claude Code CLI Driver module exist under tests/test_litellm/ (or the established test home for new utilities).
• Tests run with the rest of the unit test suite (no claude CLI dependency at test time; subprocess is mocked).
• Tests cover: argument assembly for non-streaming and streaming modes, parsing of stream-JSON output for at least the cases covered by v0 features, timeout handling, and error extraction when the CLI exits non-zero.
• Tests assert against the driver's external interface (its return value), not internal implementation details.
• Tests pass on CI alongside the existing unit test suites.

Blocked by

• Blocked by #26477

User stories addressed

Reference by number from the parent PRD:

• User story 21 (reliability of the CLI driver supports test authors)