[II] Test W4A8 QSRT rate compatibility

[voipmonitor]

Status

• Implementation: implemented
• Validation: qualified

Purpose

Protect the W4A8 QSRT planning contract enforced by commit 33cbfc70033473f85cc378da44fd8feca9c85610. W4A8 kernels decode one compile-time rate for an entire payload, while the H308 atom profiles carry per-pair K3/K4 rate selectors that require W4A16 execution.

Resulting behavior

The CPU planner tests require both mixed-rate H308 profiles to fail closed under quant_mode="w4a8_mx". The tests also require the supported coupled-K2 uniform-rate profile to retain the source-native Trellis layout.

Compatibility

This pull request changes tests only. Runtime behavior remains defined by commit 33cbfc70033473f85cc378da44fd8feca9c85610.

Validation

• Focused planner tests: 3 passed.
• Ruff check and format: passed.
• git diff --check: passed.

Summary by CodeRabbit

• Tests
  • Added coverage for validating QSRT profiles during w4a8_mx weight planning.
  • Confirmed mixed-rate profiles are rejected with an error.
  • Confirmed uniform-rate coupled profiles are accepted and use the required weight layout.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 81bdf5c0-a068-470f-8e76-b8ea02203eef

📥 Commits

Reviewing files that changed from the base of the PR and between 33cbfc7 and b6a7672.

📒 Files selected for processing (1)

• tests/moe/test_execution_model.py

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📝 Walkthrough

Walkthrough

The PR adds tests for w4a8_mx QSRT profile validation. Mixed-rate profiles must raise ValueError. A uniform-rate coupled profile must succeed and select PreparedWeightLayout.TRELLIS_NATIVE.

Changes

QSRT weight planning validation

Layer / File(s)	Summary
QSRT profile validation tests/moe/test_execution_model.py	Parameterized tests verify that mixed-rate QSRT profiles are rejected. A uniform-rate coupled profile is accepted and uses PreparedWeightLayout.TRELLIS_NATIVE.

Estimated code review effort: 2 (Simple) | ~10 minutes

Mergeability Score: ⚪ Minimal · up to b6a76

This PR adds focused planner coverage without changing runtime behavior, and no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: lukealonso

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the tests and the W4A8 QSRT rate compatibility contract covered by the changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[lukealonso]

Closing without merge. The mixed-rate W4A8 QSRT rejection remains implemented in b12x/moe/_shared/execution.py by commit 33cbfc70033473f85cc378da44fd8feca9c85610; this pull request only adds planner tests for that existing behavior.