snob-lib
A tool that only selects meaningful python tests to run.
Decision gist · record as of 2026-08-14
Yes, if you work in a large Python codebase where full test suite runs are slow and you want faster local feedback during development. The tool is actively maintained, has no runtime dependencies, and carries permissive licensing. The caveat: wheel availability only for Python 3.10+ may limit adoption on older projects despite the >=3.8 requirement claim, and static analysis cannot catch dynamic imports or runtime side-effects, so it should complement rather than replace CI regression testing.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python >=3.8 and Git for change detection; pytest plugin mode requires pytest to be installed separately.
- Medium install friction due to compiled wheels across multiple platforms and Python versions (3.10, 3.11).
- Package is actively maintained with recent activity, though only a single release so far.
License · maintenance · safety
MIT (permissive) — MIT license is permissive and imposes no restrictions on use, modification, or distribution in proprietary or open-source projects.
last release 2025-01-11 (580 days) · last repo commit 2026-06-28 · 69 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 94,273 downloads/mo, #13,335 on PyPI
Alternatives
Verify before relying
pip install snob-lib
# As CLI: list affected tests based on git changes
snob $(git diff --name-only) | xargs pytest
# Or as pytest plugin: test changes since a commit
pytest --commit-range main..HEAD- Whether the package works with Python versions below 3.10 despite claiming >=3.8 support (wheels only provided for 3.10 and 3.11).
- Performance characteristics on codebases smaller than the 'million line' example mentioned in the description.
- Accuracy of test selection when projects use dynamic imports or runtime side-effects beyond static analysis.
What it is and what it does
Snob is a test selection tool that analyzes your Python project's static import dependencies to determine which tests are affected by code changes. Rather than running your entire test suite on every change, it builds a dependency graph and outputs only the tests impacted by modified files, dramatically reducing feedback time during development.
The tool works as both a standalone CLI (piped with git diff and pytest) and as a pytest plugin. It's designed for local development workflows in large codebases where full regression testing would be prohibitively slow. Snob does not predict test failures—it selects tests based on static dependency analysis—and is explicitly not intended to replace CI or full test suite runs, but to accelerate the inner development loop by often skipping 99% of irrelevant tests.
Use it for
- Speed up local development by running only tests affected by your current code changes instead of the full suite.
- Reduce CI feedback time by using Snob to filter test runs to changed modules in pull request pipelines.
- Identify test coverage gaps by visualizing the dependency graph between code and tests using Graphviz output.
- Exclude slow integration tests or external API tests from automatic runs while keeping them available for manual execution.
- Ensure critical tests always run by marking files like conftest.py or requirements.txt to trigger full test suite on change.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you work in a large Python codebase where full test suite runs are slow and you want faster local feedback during development.
The tool is actively maintained, has no runtime dependencies, and carries permissive licensing. The caveat: wheel availability only for Python 3.10+ may limit adoption on older projects despite the >=3.8 requirement claim, and static analysis cannot catch dynamic imports or runtime side-effects, so it should complement rather than replace CI regression testing.
Install
snob-lib on PyPI
Before you install
Medium install friction due to compiled wheels across multiple platforms and Python versions (3.10, 3.11). Package is actively maintained with recent activity, though only a single release so far. No runtime dependencies simplifies deployment.
Requires Python >=3.8 and Git for change detection; pytest plugin mode requires pytest to be installed separately.
License in practice
MIT license is permissive and imposes no restrictions on use, modification, or distribution in proprietary or open-source projects.
Quickstart
pip install snob-lib
# As CLI: list affected tests based on git changes
snob $(git diff --name-only) | xargs pytest
# Or as pytest plugin: test changes since a commit
pytest --commit-range main..HEADVerify before relying
- Whether the package works with Python versions below 3.10 despite claiming >=3.8 support (wheels only provided for 3.10 and 3.11).
- Performance characteristics on codebases smaller than the 'million line' example mentioned in the description.
- Accuracy of test selection when projects use dynamic imports or runtime side-effects beyond static analysis.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 580 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 94,273 / month, #13,335 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyProgramming Language :: Rust |
Evidence: snob_lib-0.1.0-cp310-cp310-manylinux_2_12_i686.manylinux2010_i686.whl; snob_lib-0.1.0-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; snob_lib-0.1.0-cp310-cp310-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; snob_lib-0.1.0-cp310-cp310-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl; snob_lib-0.1.0-cp310-cp310-manylinux_2_17_s390x.manylinux2014_s390x.whl; snob_lib-0.1.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl; snob_lib-0.1.0-cp310-cp310-musllinux_1_2_aarch64.whl; snob_lib-0.1.0-cp310-cp310-musllinux_1_2_armv7l.whl; snob_lib-0.1.0-cp310-cp310-musllinux_1_2_i686.whl; snob_lib-0.1.0-cp310-cp310-musllinux_1_2_x86_64.whl; snob_lib-0.1.0-cp310-cp310-win32.whl; snob_lib-0.1.0-cp310-cp310-win_amd64.whl; snob_lib-0.1.0-cp311-cp311-macosx_10_12_x86_64.whl; snob_lib-0.1.0-cp311-cp311-macosx_11_0_arm64.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_12_i686.manylinux2010_i686.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_17_s390x.manylinux2014_s390x.whl; snob_lib-0.1.0-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
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