Testing

inline_snapshot.testing provides tools which can be used to test inline-snapshot workflows. This might be useful if you want to build your own libraries based on inline-snapshot.

The following example shows how you can use the Example class to test what inline-snapshot would do with given the source code. The snapshots in the argument are asserted inside the run_* methods, but only when they are provided.

original--inline-snapshot=create

from inline_snapshot.testing import Example
from inline_snapshot import snapshot


def test_something():

    Example(
        {
            "test_a.py": """\
from inline_snapshot import snapshot
def test_a():
    assert 1+1 == snapshot()
"""
        }
    ).run_inline(  # run without flags
        reported_categories=snapshot(),
    ).run_pytest(
        ["--inline-snapshot=short-report"],  # check the pytest report
        changed_files=snapshot(),
        report=snapshot(),
        returncode=snapshot(),
    ).run_pytest(  # run with create flag and check the changed files
        ["--inline-snapshot=create"],
        changed_files=snapshot(),
        returncode=snapshot(),
    )

from inline_snapshot.testing import Example
from inline_snapshot import snapshot


def test_something():

    Example(
        {
            "test_a.py": """\
from inline_snapshot import snapshot
def test_a():
    assert 1+1 == snapshot()
"""
        }
    ).run_inline(  # run without flags
        reported_categories=snapshot(["create"]),
    ).run_pytest(
        ["--inline-snapshot=short-report"],  # check the pytest report
        changed_files=snapshot({}),
        report=snapshot(
            """\
Error: one snapshot is missing a value (--inline-snapshot=create)
You can also use --inline-snapshot=review to approve the changes interactively\
"""
        ),
        returncode=snapshot(1),
    ).run_pytest(  # run with create flag and check the changed files
        ["--inline-snapshot=create"],
        changed_files=snapshot(
            {
                "test_a.py": """\
from inline_snapshot import snapshot
def test_a():
    assert 1+1 == snapshot(2)
"""
            }
        ),
        returncode=snapshot(1),
    )

API

Example

__init__(files)

Parameters:

Name	Type	Description	Default
files	str | dict[str, str | bytes]	a collection of files where inline-snapshot operates on, or just a string which will be saved as test_something.py.	required

run_inline(args=[], *, reported_categories=None, changed_files=None, report=None, raises=None)

Execute the example files in process and run every test_* function.

This is useful for fast test execution.

Parameters:

Name	Type	Description	Default
args	list[str]	inline-snapshot arguments (supports only "--inline-snapshot=fix|create|..." ).	[]
reported_categories	Snapshot[list[Category]] | None	snapshot of categories which inline-snapshot thinks could be applied.	None
changed_files	Snapshot[dict[str, str]] | None	snapshot of files which are changed by this run.	None
raises	Snapshot[str] | None	snapshot of the exception which is raised during the test execution. It is required if your code raises an exception.	None

Returns:

Type	Description
Example	A new Example instance which contains the changed files.

run_pytest(args=[], *, term_columns=80, env={}, changed_files=None, report=None, error=None, stderr=None, returncode=0, stdin=b'', outcomes=None)

Run pytest with the given args and env variables in an separate process.

It can be used to test the interaction between your code and pytest, but it is a bit slower than run_inline

Parameters:

Name	Type	Description	Default
args	list[str]	pytest arguments like "--inline-snapshot=fix"	[]
env	dict[str, str]	dict of environment variables	{}
changed_files	Snapshot[dict[str, str]] | None	snapshot of files which are changed by this run.	None
report	Snapshot[str] | None	snapshot of the report at the end of the pytest run.	None
stderr	Snapshot[str] | None	pytest stderr output	None
returncode	Snapshot[int]	snapshot of the pytest returncode.	0

Returns:

Type	Description
Example	A new Example instance which contains the changed files.