sglang/test

Run Unit Tests

SGLang uses the built-in library unittest as the testing framework.

Test Backend Runtime

cd sglang/test/srt

# Run a single file
python3 test_srt_endpoint.py

# Run a single test
python3 test_srt_endpoint.py TestSRTEndpoint.test_simple_decode

# Run a suite with multiple files
python3 run_suite.py --suite per-commit

Test Frontend Language

cd sglang/test/lang

# Run a single file
python3 test_choices.py

Adding or Updating Tests in CI

• Create new test files under test/srt or test/lang depending on the type of test.
• Ensure they are referenced in the respective run_suite.py (e.g., test/srt/run_suite.py) so they are picked up in CI. For most small test cases, they can be added to the per-commit-1-gpu suite. Sort the test cases alphabetically by name.
• Ensure you added unittest.main() for unittest and pytest.main([__file__]) for pytest in the scripts. The CI run them via python3 test_file.py.
• The CI will run some suites such as per-commit-1-gpu, per-commit-2-gpu, and nightly-1-gpu automatically. If you need special setup or custom test groups, you may modify the workflows in .github/workflows/.

Writing Elegant Test Cases

• Learn from existing examples in sglang/test/srt.
• Reduce the test time by using smaller models and reusing the server for multiple test cases. Launching a server takes a lot of time.
• Use as few GPUs as possible. Do not run long tests with 8-gpu runners.
• If the test cases take too long, considering adding them to nightly tests instead of per-commit tests.
• Keep each test function focused on a single scenario or piece of functionality.
• Give tests descriptive names reflecting their purpose.
• Use robust assertions (e.g., assert, unittest methods) to validate outcomes.
• Clean up resources to avoid side effects and preserve test independence.
• Reduce the test time by using smaller models and reusing the server for multiple test cases.

Adding New Models to Nightly CI

• For text models: extend global model lists variables in test_utils.py, or add more model lists
• For vlms: extend the MODEL_THRESHOLDS global dictionary in test_nightly_vlms_.*.py, see here