# All tests - parallel across every core (pytest-xdist, `-n auto` in pytest.ini)
pytest tests/ -v
# Single file - naming test files runs them in one process, since a worker's
# torch import costs more than it saves there; -n N forces workers anyway
pytest tests/test_security.py -v
# Debugging with -s or --pdb needs one process
pytest tests/ -n0 -s
# The real-model tests (an accelerator, plus SD 1.5 and facebook/mms-tts-eng,
# which download on first run) are the release gate, and are
# excluded by default; one process, since each test holds a model on the device
pytest tests/ -m integration -n0
# Match pattern
pytest tests/ -k "variables" -v
# Stop on first failure
pytest tests/ -x
# With coverage
pytest tests/ --cov=dw --cov-report=html
# Open htmlcov/index.html to view reportAround 120 files and 3,600+ tests as of this writing (pytest tests/ --collect-only -q for the current count). The table below maps the core areas; newer features carry their own test_<feature>.py alongside them (server: test_server.py, events/cancellation: test_events.py, test_worker_execute.py, introspection: test_introspection.py, hub cache: test_hub_cache.py, chaining: test_chain.py).
| File | Area |
|---|---|
| test_security.py | Path, URL, input validation |
| test_variables.py | Variable substitution |
| test_workflow.py | Workflow loading, validation, result eviction, seed resolution |
| test_previous_results.py | Cross-step result references / cartesian products |
| test_result.py | Output file handling |
| test_arguments.py | Argument processing and type conversion |
| test_step.py | Step execution |
| test_gather.py | Resource gathering tasks |
| test_type_helpers.py | Dynamic type loading |
| test_integration.py | End-to-end workflow tests |
| test_task.py | Task dispatch |
| test_schema.py | JSON schema validation |
| test_worker.py | Worker subprocess |
| test_worker_manager.py | Worker process lifecycle management |
| test_pipeline_caching.py, test_pipeline_components.py, test_modular_pipeline.py | Pipeline caching, component discovery, load_components |
| test_device.py, test_device_helpers.py | Device selection, shared device/dtype helpers |
| test_image_utils.py, test_resize_bucket.py, test_strip_exif_and_watermark.py, test_tensor_image.py, test_list_images.py | Image processing task commands |
| test_diffusion_upscale.py, test_interpolate_frames.py, test_depth_estimator.py, test_segment.py | Diffusion upscale, RIFE interpolation, depth hints, segmentation |
| test_image_to_text.py, test_text_generation.py | Captioning and text generation tasks |
| test_model_cache.py | Shared task model cache |
| test_prompt_weighting.py | Prompt weighting device handling |
| test_argument_updates.py | Cached pipelines pick up fresh arguments across runs |
| test_examples.py | Validates every workflow in workflows/ against the schema |
| test_mcp_client.py, test_mcp_catalog.py, test_mcp_authoring.py, test_mcp_diagnose.py, test_mcp_media.py, test_mcp_server.py | MCP tool surface |
The MCP tests fake the REST API with httpx.MockTransport — they never
start a dw.serve process and never touch a GPU. test_mcp_server.py
(which builds a real MCPServer and calls tools through it) skips with
pytest.importorskip("mcp", ...) when the mcp extra is not installed.
An autouse _clear_task_model_cache fixture clears dw.tasks.model_cache before and after every test, so a cache hit in one test can't starve a later test's mocked loader of the call it expects. Test-specific fixtures (test_data_dir, temp_output_dir, temp_image, valid_workflow_json, etc.) are also defined here — see tests/README.md for the list.
# End-to-end check: downloads SD 1.5 and generates one image
python -m dw.test
# Validate a workflow against schema
python -m dw.validate workflows/models/flux-dev.json