syrupy 0.0.9

PyTest Snapshot Test Utility

syrupy

Overview

Syrupy is a pytest snapshot plugin. It enables developers to write tests which assert immutability of computed results.

Motivation

The most popular snapshot test plugin compatible with pytest has some core limitations which this package attempts to address by upholding some keys values:

• Extensible: If a particular data type is not supported, users should be able to easily and quickly add support.
• Idiomatic: Snapshot testing should fit naturally among other tests cases in pytest, e.g. assert x == snapshot vs. snapshot.assert_match(x).
• Soundness: Snapshot tests should uncover even the most minute issues. Unlike other snapshot libraries, Syrupy will fail a test suite if a snapshot does not exist, not just on snapshot differences.

Installation

python -m pip install syrupy

Usage

Basic Usage

In a pytest test file test_file.py:

def test_foo(snapshot):
    actual = "Some computed value!"
    assert actual == snapshot

when you run pytest, the above test should fail due to a missing snapshot. Re-run pytest with the update snapshots flag like so:

pytest --snapshot-update

A snapshot file should be generated under a __snapshots__ directory in the same directory as test_file.py. The __snapshots__ directory and all its children should be committed along with your test code.

Advanced Usage, Plugin Support

import pytest

@pytest.fixture
def snapshot_custom(snapshot):
    return snapshot.with_class(
        serializer_class=CustomSerializerClass,
    )

def test_image(snapshot_custom):
    actual = "..."
    assert actual == snapshot_custom

CustomSerializerClass should extend syrupy.serializers.base.AbstractSnapshotSerializer.

Uninstalling

pip uninstall syrupy

Contributing

Feel free to open a PR. This project is still in a very early stage, and we're still figuring out what direction we want to move towards.

To develop locally, clone this repository and run . script/bootstrap to install test dependencies. You can then use invoke --list to see available commands.

Contributors

Noah 🚇 🤔 💻 📖 ⚠️

Emmanuel Ogbizi 💻 🎨 🚇 📖 ⚠️

This section is automatically generated via tagging the all-contributors bot in a PR:

@all-contributors please add <username> for <contribution type>

Related Links

• JavaScript snapshot testing: jest

License

See: ./LICENSE