Unchanged

A simple approvals/snapshot/golden master library that lets you configure your testing tools any way you want.

Features

• Sensible defaults: Just want to do some basic snapshot on most Python objects? Go for it. Snapshot testing should be easy.
• Highly Modular: Want to do fuzzy comparison, pre-check file scrubbing, have the diff display in a non-Python program, and use the latest test runner? No problem, plug your tools and functions into unchanged based on your own preferences and project needs.
• No External Dependencies: unchanged's internals are stupidly simple, using only the Python standard library--you decide what packages your tests will rely on, not us.

Installation

pip install unchanged

Example Usage

from unchanged import verify

Hello world is still "Hello world"

from unchanged import verify

verify("Hello, world", path="greeting.txt")

Use Git Diff to Compare files

With subprocess:

from unchanged import Verifier
from subprocess import Popen

verify = Verifier(show_diffs=lambda f1, f2: Popen(['git' ,'diff', '--no-index', f1, f2]))
verify("Hello, world", path='greeting.txt')

With the unchanged.Program utility:

from unchanged import Verifier, Program

verify = Verifier(show_diffs=Program(['git' ,'diff', '--no-index']))
verity("Hello world")

Use NBDime to Compare Jupyter Notebooks

from unchanged import Verifier
from subprocess import Popen

notebooks_match = lambda f1, f2: Popen(['nbdime', 'diff', '--ignore-metadata', f1, f2]).stdout.read() == ''
show_notebook_diff = lambda f1, f2: Popen(['nbdime', 'diff-web'])

verify_notebook = Verifier(show_diffs=Program(['nbdime', 'diff-web']), files_match=notebooks_match)

Use BeyondCompare 3 to Display Diffs

from unchanged import Verifier
from subprocess import Popen

path_to_bc3 = "{ProgramFiles}/Beyond Compare 4/BCompare.exe"
show_diff_in_BC3 = lambda f1, f2: Popen([path_to_bc3])

verify = Verifier(show_diffs=show_diff_in_BC3)

Check Matplotlib Plots, Displaying Diffs in VSCode

from unchanged import Verifier
from subprocess import Popen