nano-vllm/.claude/rules/testing.md

Testing

Test File Guidelines

Naming Convention

• All test files must be named test_*.py
• Example: test_offload_engine.py, test_ring_buffer.py

Purpose

Tests are educational scripts for understanding module behavior, NOT traditional unit tests:

• Focus on demonstrating how modules work
• Show the flow and interaction between components
• Help developers understand implementation details

Code Style

1. Script-based structure: Write tests as executable scripts, not pytest-style functions
2. Utility functions: Extract reusable steps as helper functions at the top of the file
3. Main flow as script: The actual test/demonstration logic runs as top-level script code

# Example structure:

import torch
from nanovllm.kvcache import SomeModule

# ============================================================
# Utility Functions
# ============================================================

def verify(tensor, expected, name):
    actual = tensor.mean().item()
    assert abs(actual - expected) < 0.01, f"{name}: {actual} != {expected}"

# ============================================================
# Main Test Script
# ============================================================

# 1. Initialize
module = SomeModule(param=value)

# 2. Test feature X
result = module.do_something()
assert result == expected_value

# 3. Test feature Y
...

print("test_xxx: PASSED")

Comments

• Keep comments concise and clear
• Only add comments where the code isn't self-explanatory
• Use section headers (# === Section ===) to organize logical blocks

Output

• Minimize print statements - the code should be self-explanatory
• Only print a final "PASSED" message at the end
• Use assert for verification instead of printing results
• If the user needs explanation, they will ask

Running Tests

Use PYTHONPATH for multi-instance isolation (no pip install needed):

# Run a specific test
PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python tests/test_offload_engine.py

# Run with specific GPU
CUDA_VISIBLE_DEVICES=0 PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python tests/test_ring_buffer.py

Benchmarks

PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python bench.py
PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python bench_offload.py
PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python bench_vllm.py

Quick Verification

# Import test
PYTHONPATH=/path/to/nano-vllm:$PYTHONPATH python -c "from nanovllm import LLM"