dev-testing-python

name	dev-testing-python
description	Python test infrastructure for capsem-builder. Use when running Python tests, checking coverage, or working with golden fixtures and generated schemas.

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=85  # 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/

File	Tests	What it covers
test_validate.py	96	TOML config linting, error codes E001-E305, warnings W001-W012
test_models.py	80	Pydantic models (GuestImageConfig, ArchConfig, all sub-models)
test_cli.py	18	Backend-only Click CLI surface; product build/validate/inspect commands stay burned
test_docker.py	75	Jinja Dockerfile rendering, conformance with legacy Dockerfiles
test_settings_spec.py	73	Settings schema conformance (golden fixture round-trip)
test_manifest.py	48	BOM collection, manifest rendering, dpkg/pip/npm parsers
test_config.py	41	TOML config loading, defaults generation, roundtrip
test_doctor.py	27	Build doctor checks (Docker, tools, disk, permissions)
test_mcp.py	20	JSON-RPC 2.0 MCP stdio server
test_audit.py	20	Trivy/grype JSON parsing, severity summary

Coverage

• Floor: 85% enforced by --cov-fail-under=85 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:

Language	Test file	Tests
Python	tests/test_settings_spec.py	73
Rust	crates/capsem-core/tests/settings_spec.rs	12
TypeScript	frontend/src/lib/__tests__/settings_spec.test.ts	14

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

Schema generation pipeline

config/settings/settings.toml -> Pydantic models -> config/settings/schema.generated.json (JSON Schema)
                                                   -> config/settings/ui-metadata.generated.json (UI metadata)

• just schema runs generate_schema.py which calls export_json_schema() and generate_defaults_json()
• Rust reads config/settings/ui-metadata.generated.json via include_str!() in registry.rs
• TypeScript validates against config/settings/schema.generated.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 exec "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           Backend-only 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
        audit.py          Trivy/grype output parsing
        image_build_backend.py Private capsem-admin image build backend
        doctor.py         Build environment doctor checks
        templates/
            Dockerfile.rootfs.j2
            Dockerfile.kernel.j2