Files
sglang/test/registered/unit
laoyao0822 142e7a5a64 Keep CP shared-KV fast paths off dense current collectives
CP shared-KV cache-hit batches should compose long prefix pages and short current pages through page-slot IPC instead of falling back to dense all_reduce. Wire the runtime and prefetch consume paths to the TAI current-staging helpers, fail fast when the configured CUDA fast path cannot run, and document the bs>1 cache-hit benchmark evidence.

Constraint: bs>1 prefill must preserve the page-slot contract across fp8/bf16 and zero-lane current tails.

Rejected: Silent all_reduce fallback | hides correctness and performance regressions in production.

Confidence: medium

Scope-risk: moderate

Directive: Any future fallback in CP shared-KV CUDA fast paths must be explicit warning/fail-fast and covered by runtime tests.

Tested: Local py_compile cp_shared_kv_runtime.py and cp_shared_kv_prefetch.py; remote PYTHONPATH=python pytest -q test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py (144 passed, 21 warnings, 2 subtests passed); remote TAI IPC benchmark fp8 bs>1 cache-hit matrix recorded in docs.

Not-tested: Full ETE mixed replay after replacing all current collectives with IPC.
(cherry picked from commit 8aa3b4ce59e0ebef5da5b0d07499a5f1d9785997)
2026-06-13 00:58:47 +08:00
..

Unit Tests

Component-level tests that do not launch a server or load model weights. Tests can use CPU or GPU — the key criterion is no server process.

Quick Start

  1. Find the source file under python/sglang/srt/.
  2. Create the corresponding test here, mirroring the source tree:
    srt/mem_cache/radix_cache.py       →  unit/mem_cache/test_radix_cache.py
    srt/sampling/sampling_params.py    →  unit/sampling/test_sampling_params.py
    
  3. Register for CI at the top of the file (after imports, before test classes):
    from sglang.test.ci.ci_register import register_cpu_ci
    register_cpu_ci(est_time=5, suite="stage-a-test-cpu")
    # or: register_cuda_ci(est_time=10, suite="stage-b-test-1-gpu-small")
    
  4. Run locally:
    pytest test/registered/unit/ -v            # all unit tests
    pytest test/registered/unit/mem_cache/ -v  # one module
    
  5. Run with coverage:
    # summary
    pytest test/registered/unit/ --cov --cov-config=.coveragerc -v
    
    # PR incremental check (require ≥60% on changed lines)
    pytest test/registered/unit/ --cov --cov-config=.coveragerc --cov-report=xml
    diff-cover coverage.xml --compare-branch=origin/main --fail-under=60
    

Example

"""Unit tests for <module> — no server, no model loading."""

from sglang.test.ci.ci_register import register_cpu_ci

register_cpu_ci(est_time=5, suite="stage-a-test-cpu")

import unittest

from sglang.srt.<module> import TargetClass
from sglang.test.test_utils import CustomTestCase


class TestTargetClass(CustomTestCase):
    def test_basic_behavior(self):
        obj = TargetClass(...)
        self.assertEqual(obj.method(), expected)


if __name__ == "__main__":
    unittest.main()

Rules

  • No popen_launch_server() or Engine(...).
  • No model weight loading.
  • Use CustomTestCase (from sglang.test.test_utils, adds CI retry).
  • Use unittest.mock for dependencies that are expensive to construct.