approvaltests
Assertion/verification library to aid testing
Decision gist · record as of 2026-08-14
Yes. ApprovalTests fills a genuine gap in Python testing: snapshot-based verification for outputs too complex for simple assertions. Active maintenance, low install friction, permissive license, no known vulnerabilities, and broad Python version support (3.10–3.14) make it a solid choice. Install it if you regularly test long strings, structured objects, or generated content where a diff tool beats manual assertion logic.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires pytest or unittest as your test runner; reporters (diff tools) are optional but recommended for viewing approval failures.
- Low install friction: pure Python wheel with no compiled dependencies.
- Active maintenance—last commit 2026-08-10, released 2026-08-02.
License · maintenance · safety
Apache-2.0 (permissive) — Apache-2.0 (permissive): you may use, modify, and distribute this package freely in commercial and open-source projects, provided you include a copy of the license and state any material changes.
last release 2026-08-02 (12 days) · last repo commit 2026-08-10 · 209 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 167,975 downloads/mo, #10,458 on PyPI
Alternatives
Verify before relying
pip install approvaltests
from approvaltests.approvals import verify
def test_simple():
result = "Hello ApprovalTests"
verify(result)- Whether the 10 runtime dependencies (pytest, beautifulsoup4, pyperclip, etc.) are all required or only needed for specific features.
- Performance characteristics when verifying very large objects or arrays.
What it is and what it does
ApprovalTests is a snapshot-based testing library that compares test output against previously approved golden-master files. Instead of writing brittle assertions for complex objects, you capture the actual output, review it in a diff tool, and approve it as the expected result. On subsequent runs, any deviation from the approved output triggers a diff comparison, letting you decide whether the change is intentional or a regression.
The library integrates with pytest and unittest, supports CLI invocation for cross-language testing, and includes reporters that launch external diff tools (like your system's native diff viewer or IDE integrations). It handles long strings, large arrays, HTML, and structured objects—scenarios where line-by-line assertion code becomes unwieldy. Extra dependencies unlock optional features like clipboard reporting, HTML verification, and pairwise test combination.
Use it for
- Verify multi-line text output or formatted reports without writing fragile string comparisons.
- Test complex nested data structures (dicts, lists, objects) by comparing their serialized form to an approved snapshot.
- Review HTML generation or template output using a visual diff tool instead of regex assertions.
- Detect unintended changes in API responses or large JSON structures across test runs.
- Manage test data for exercises, katas, or green-field projects using the starter project template.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
ApprovalTests fills a genuine gap in Python testing: snapshot-based verification for outputs too complex for simple assertions. Active maintenance, low install friction, permissive license, no known vulnerabilities, and broad Python version support (3.10–3.14) make it a solid choice. Install it if you regularly test long strings, structured objects, or generated content where a diff tool beats manual assertion logic.
Install
approvaltests on PyPI
Before you install
Low install friction: pure Python wheel with no compiled dependencies. Active maintenance—last commit 2026-08-10, released 2026-08-02. Requires Python 3.10 or later; tested on 3.10, 3.11, 3.12, 3.13, 3.14.
Requires pytest or unittest as your test runner; reporters (diff tools) are optional but recommended for viewing approval failures.
License in practice
Apache-2.0 (permissive): you may use, modify, and distribute this package freely in commercial and open-source projects, provided you include a copy of the license and state any material changes.
Quickstart
pip install approvaltests
from approvaltests.approvals import verify
def test_simple():
result = "Hello ApprovalTests"
verify(result)Verify before relying
- Whether the 10 runtime dependencies (pytest, beautifulsoup4, pyperclip, etc.) are all required or only needed for specific features.
- Performance characteristics when verifying very large objects or arrays.
Package facts
| License | Apache-2.0 permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 10 packagespytestempty-filestyping_extensionspyperclipbeautifulsoup4allpairspytestfixturesmockpsutilapproval_utilities |
| Maintenance | Actively maintained 12 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 167,975 / month, #10,458 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaIntended Audience :: DevelopersOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIXProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Topic :: Software Development :: LibrariesTopic :: Software Development :: TestingTopic :: Utilities |
Evidence: approvaltests-19.1.1-py3-none-any.whl
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See also approval-utilities · expecttest · testtools · snapshottest · qase-python-commons · pytest-snapshot · datadiff · pytest-clarity · pytest-insta · pytest-html-reporter