Cycle and internal-dependency rules
Architecture testing for Python
ArchUnitPython
Turn imports and source structure into rules that run beside pytest or unittest. ArchUnitPython checks boundaries, cycles, layers, external dependencies, code metrics, and architecture diagrams without becoming a production dependency.
PyPI
pip install archunitpythonfrom archunitpython import project_files, assert_passes
def test_domain_stays_independent():
rule = (
project_files('src/')
.in_folder('**/domain/**')
.should_not()
.depend_on_files()
.in_folder('**/infrastructure/**')
)
assert_passes(rule)Capabilities
What ArchUnitPython brings to the test suite.
The family shares a recognizable architecture vocabulary while each implementation stays honest about its language, toolchain, and maturity.
Named layers and forbidden external imports
Counting, cohesion, and distance metrics
pytest, unittest, and framework-neutral checks
Ignore files and JSON-configured common rules
Dependency graph snapshots and exports
Current maturity
Production ready
Published on PyPI, designed with zero runtime dependencies, and compatible with ordinary Python testing workflows.
LanguagePython
ReleasePublished package
RuntimePython projects
LicenseMIT
Where it fits
Put boundaries next to the code they protect.
Common starting points for ArchUnitPython include the following project shapes.
Django boundariesFastAPI servicesData platformsRAG pipelines
More ecosystems
The same intent, expressed natively.
Explore sibling implementations and carry the architecture vocabulary across a polyglot system.
Production ready
TypeScript
ArchUnitTS
Architecture tests for TypeScript and JavaScript, from dependency rules to metrics and diagrams.
Alpha preview
.NET
ArchUnit.NET
Architecture rules and reports for C# solutions, with adapters for major .NET test frameworks.
Main-branch preview
Go
ArchUnitGo
Architecture policies as plain Go test values, backed by the Go toolchain and x/tools.
Make the first boundary executable.
Add one meaningful rule, run it with the existing tests, and grow the architecture suite as the system reveals where it needs protection.
Start with ArchUnitPython ↗