name: dev-testing-python description: Python test infrastructure for the capsem-builder package. Use when running Python tests, checking coverage, debugging test failures, working with golden fixtures, or generating schemas. Covers pytest config, coverage floors, cross-language conformance tests, and the schema generation pipeline.

Python Testing (capsem-builder)

Quick reference

uv run python -m pytest tests/                                    # All tests
uv run python -m pytest tests/ --cov=src/capsem --cov-fail-under=90  # With coverage
uv run python -m pytest tests/test_validate.py -k "test_E001"     # Single test
just test                                                          # Full suite (Rust + Python + frontend)
just schema                                                        # Regenerate JSON schema + defaults

Package config

pyproject.toml:

• Package: capsem, entry point capsem-builder = capsem.builder.cli:main
• Build: hatchling, wheel packages src/capsem
• Test deps: pytest>=8.0, pytest-cov>=6.0 (in [dependency-groups] dev)
• testpaths = ["tests"]

Test directory: tests/

Coverage

• Floor: 90% enforced by --cov-fail-under=90 in just test
• Report: codecov-python.xml (XML for CI upload)
• codecov.yml: builder component at src/capsem/**, included in unit flag
• Current: ~97% (as of Phase 7 completion)

Golden fixtures and cross-language conformance

Golden fixture at tests/settings_spec/golden.json with expected output at tests/settings_spec/expected.json. Three language parsers must produce identical results:

If you change the settings schema (node types, metadata fields), all three must be updated together.

Schema generation pipeline

guest/config/*.toml -> Pydantic models -> config/settings-schema.json (JSON Schema)
                                       -> config/defaults.json (settings interchange)

• just schema runs generate_schema.py which calls export_json_schema() and generate_defaults_json()
• Rust reads config/defaults.json via include_str!() in registry.rs
• TypeScript validates against config/settings-schema.json in conformance tests

In-VM tests (NOT pytest on host)

guest/artifacts/diagnostics/ contains 207 pytest tests that run INSIDE the VM via just run "capsem-doctor". These are NOT part of the host uv run pytest suite. They test the guest environment (mounts, networking, sandbox, MCP, runtimes). See /dev-testing-vm for details.

Source layout

src/capsem/
    __init__.py
    builder/
        __init__.py
        cli.py           Click CLI entry point
        config.py         TOML config loading, defaults generation
        models.py         Pydantic models (GuestImageConfig, ArchConfig, etc.)
        schema.py         Settings schema (SettingsRoot, GroupNode, SettingNode)
        docker.py         Jinja Dockerfile rendering, Docker build execution
        manifest.py       BOM collection, manifest rendering
        validate.py       Compiler-style linting with error codes
        scaffold.py       init/add scaffolding
        audit.py          Trivy/grype output parsing
        mcp_server.py     JSON-RPC 2.0 MCP stdio server
        doctor.py         Build environment doctor checks
        templates/
            Dockerfile.rootfs.j2
            Dockerfile.kernel.j2