inline-snapshot is a new tool that I am trying out for python testing. It takes snapshots of your outputs and places them inline with the test.

Here is the most basic starter.

import inline_snapshot

def test_one():
    assert 1 == snapshot()

Now when I run pytest my tests will fail because my assert has no value, but if I run pytest --inline-snapshot=create it will fill out my snapshot values and the file will then look like this.

import inline_snapshot

def test_one():
    assert 1 == snapshot(1)

It also works with pydantic models.

class MyModel(BaseModel):
    name: str
    age: int
    nickname: str | None = None

def test_my_model_instance():
    assert MyModel(name="Waylon", age=1) == snapshot(MyModel(name="Waylon", age=1))

def test_my_model_fields():
    me = MyModel(name="Waylon", age=1, nickname='Waylon')
    assert == snapshot("Waylon")
    assert me.age == snapshot(1)
    assert me.nickname == snapshot("Waylon")