Fixture File Handler

This project helps you to vacate specific file path or deploy resource file into specific file path when unit testing.

Context

The most popular setup / teardown tasks about file system on unit testing is almost 2 kinds.

1. vacate specific file path for testing file export function
2. deploy fixture file / directory into specific file path for testing file import /export function

Then we have to think about how to back up existing file / directory between unit testing because maybe developer wants to keep those handwritten files for development.

Fixture File Handler is framework to realize simply implement the vacate and deploy actions while keeping the existing files. Of course, even if there is no file in the target path, it works fine.

Ubiquitous Language

target

The target file path to vacate or deploy file / directory for unit testing.

backup

The file path to back up existing file / directory on target file path between unit testing.

resource

The file / directory you want to deploy and let product code read / write in unit testing. It may test resource file or template file like *.dist file.

Basic behavior

Vacator

target path	backup path
existing file /dir

↓ setup

target path	backup path
	existing file / dir

↓ teardown

target path	backup path
existing file / dir

Deployer

target path	backup path	resource path
existing file / dir		resource file / dir

↓ setup

target path	backup path	resource path
resource file / dir	existing file /dir	resource file / dir

↓ teardown

target path	backup path	resource path
existing file / dir		resource file / dir

Common behavior

If file / directory already exists on backup path, setup raise BackupAlreadyExistError because it's unexpected situation and developer may want to resque those backup files.

Quickstart

1. Install

pip install fixturefilehandler

2-1. Case when unittest: implement setUp() and doCleanups()

from pathlib import Path
import unittest

from fixturefilehandler.factories import VacatorFactory
from fixturefilehandler.file_paths import RelativeVacateFilePath

VACATOR = VacatorFactory.create(
    RelativeVacateFilePath(
        Path('test.txt'),
        Path('test.txt.bak'),
        Path(__file__).parent
    )
)


class ConfigurableTestCase(unittest.TestCase):
    def setUp(self):
        VACATOR.setup()

    def doCleanups(self):
        VACATOR.teardown()

2-2. Case when pytest: implement fixture

from pathlib import Path
import pytest

from fixturefilehandler.factories import DeployerFactory
from fixturefilehandler.file_paths import RelativeDeployFilePath

DEPLOYER = DeployerFactory.create(
    RelativeDeployFilePath(
        Path('test.txt'),
        Path('test.txt.bak'),
        Path('testresources/test.txt.dist'),
        Path(__file__).parent
    )
)


@pytest.fixture
def fixture_file():
    DEPLOYER.setup()
    yield DEPLOYER.FILE_PATH
    DEPLOYER.teardown()


def test_something(fixture_file):
    """test something"""

API

file_paths

SimpleVacateFilePath

This instance holds path to target and backup. Each path is independent each other.

SimpleDeployFilePath

This instance holds path to target, backup, and resource. Each path is independent each other.

RelativeVacateFilePath

This instance holds path to target, backup, and base. Each path is relative based on base path.

RelativeDeployFilePath

This instance holds path to target, backup, resource, and base. Each path is relative based on base path.

How do I...

Use different paths for each test?

setup() and teardown() also accept file_paths argument.

Case when unittest:

from pathlib import Path

import unittest

from fixturefilehandler import ResourceFileDeployer
from fixturefilehandler.file_paths import RelativeDeployFilePath


class AdvancedConfigurableTestCase(unittest.TestCase):
    @property
    def file_path(self) -> RelativeDeployFilePath:
        return RelativeDeployFilePath(
            Path('test.txt'),
            Path('test.txt.bak'),
            Path(f'testresources/{self._testMethodName}.txt'),
            Path(__file__).parent
        )

    def setUp(self):
        ResourceFileDeployer.setup(self.file_path)

    def doCleanups(self):
        ResourceFileDeployer.teardown(self.file_path)

Case when pytest:

from pathlib import Path

import pytest

from fixturefilehandler import ResourceFileDeployer
from fixturefilehandler.file_paths import RelativeDeployFilePath


@pytest.fixture
def fixture_file_advanced(request):
    file_path = RelativeDeployFilePath(
        Path('test.txt'),
        Path('test.txt.bak'),
        Path(f'testresources/{request.node.name}.txt'),
        Path(__file__).parent
    )

    ResourceFileDeployer.setup(file_path)
    yield file_path
    ResourceFileDeployer.teardown(file_path)


def test_something(fixture_file_advanced):
    """test something"""