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.

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

"""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()

• 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.