/ΛsirΙpΔ/
Syrupy is a pytest snapshot plugin. It enables developers to write tests which assert immutability of computed results.
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.
python -m pip install syrupy
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 --update-snapshots
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.
import pytest
@pytest.fixture
def snapshot_custom(snapshot):
return snapshot.with_class(
io_class=CustomIOClass,
serializer_class=CustomSerializerClass,
)
def test_image(snapshot_custom):
actual = "..."
assert actual == snapshot_custom
Both CustomIOClass
and CustomSerializerClass
should extend syrupy.io.SnapshotIO
and syrupy.io.SnapshotSerializer
respectively.
pip uninstall syrupy
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 --help
to see a list of commands.
Noah π π€ π» π |
Emmanuel Ogbizi π» π¨ π |
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