Programming by contract
Project description
Deal -- python library for design by contract (DbC) and checking values, exceptions, and side-effects. Read intro to get started.
Features
- Classic DbC: precondition, postcondition, invariant.
- Tracking exceptions and side-effects.
- Property-based testing.
- Static checker.
- Integration with pytest, flake8, and hypothesis.
- Type annotations support.
- External validators support.
- Contracts for importing modules.
- Can be enabled or disabled on production.
- Colorless: annotate only what you want. Hence, easy integration into an existing project.
- Colorful: syntax highlighting for every piece of code in every command.
- DRY: test discovery, error messages generation.
- Partial execution: linter executes contracts to statically check possible values.
Deal in 30 seconds
# the result is always non-negative
@deal.post(lambda result: result >= 0)
# the function has no side-effects
@deal.pure
def count(items: List[str], item: str) -> int:
return items.count(item)
# test case
@pytest.mark.parametrize('case', deal.cases(count))
def test_count(case: deal.TestCase):
case()
Now we can:
- Run
python3 -m deal lintorflake8to statically check errors. - Run
python3 -m deal testorpytestto generate and run tests. - Just use the function in the project and check errors in runtime.
Read more in the documentation.
Installation
python3 -m pip install --user deal
Contributing
Contributions are welcome! A few ideas what you can contribute:
- Add new checks for the linter.
- Improve documentation.
- Add more tests.
- Improve performance.
- Found a bug? Fix it!
- Made an article about deal? Great! Let's add it into the
README.md. - Don't have time to code? No worries! Just tell your friends and subscribers about the project. More users -> more contributors -> more cool features.
Thank you :heart:
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
deal-4.2.0.tar.gz
(61.4 kB
view details)
Built Distribution
deal-4.2.0-py3-none-any.whl
(126.6 kB
view details)
File details
Details for the file deal-4.2.0.tar.gz.
File metadata
- Download URL: deal-4.2.0.tar.gz
- Upload date:
- Size: 61.4 kB
- Tags: Source
- Uploaded using Trusted Publishing? No
- Uploaded via: DepHell/0.8.3
File hashes
| Algorithm | Hash digest | |
|---|---|---|
| SHA256 | 243ec7bf895b8e95f8e5f5dc3b015660cf7ebe28945c952463db7a6df129f4fa |
|
| MD5 | 79a009e1a5de050dfdcbd16f076e260f |
|
| BLAKE2b-256 | 4d7f2d174ca25f88eab0389296b6d91dfe7f30ec037f4b24669d26d549d06e74 |
File details
Details for the file deal-4.2.0-py3-none-any.whl.
File metadata
- Download URL: deal-4.2.0-py3-none-any.whl
- Upload date:
- Size: 126.6 kB
- Tags: Python 3
- Uploaded using Trusted Publishing? No
- Uploaded via: DepHell/0.8.3
File hashes
| Algorithm | Hash digest | |
|---|---|---|
| SHA256 | 24046b608815c6a6eb073844a12dd8e3f582bb1208112fdcf501431bf0ff137f |
|
| MD5 | 1c54d92a1ad195c80c30a7b825fc6a52 |
|
| BLAKE2b-256 | 113a2f776d7dd7be2dd9c11ab31463067c1b6428760213a588616390dbb689aa |
