pytest-remaster 0.0.1a0

Golden master testing for pytest with automatic regeneration.

pytest-remaster

Framework for golden master testing for pytest with automatic regeneration of the golden master.

Installation

pip install pytest-remaster

Quick start

Create test case directories with input files and expected output files:

tests/cases/
  greet/hello/
    command          # input: "hello Alice"
    result_0         # expected: "[#general] :wave: Hello, Alice!"
  greet/goodbye/
    command          # input: "goodbye Bob"
    result_0         # expected: "[#general] :wave: Goodbye, Bob!"
    result_1         # expected: "[#general] :door: Bob has left the chat."

Write a parametrized test:

from pathlib import Path

import pytest

from pytest_remaster import GoldenMaster, discover_test_cases

CASES_DIR = Path(__file__).parent / "cases"


@pytest.mark.parametrize("case", discover_test_cases(CASES_DIR))
def test_command(case: Path, golden_master: GoldenMaster) -> None:
    cmd = (case / "command").read_text().strip()
    golden_master.check_all(lambda: run_command(cmd), directory=case)

discover_test_cases finds leaf directories and generates nice test IDs automatically (e.g. test_command[greet/hello]).

API

golden_master fixture

check(actual, expected_path, serializer=str) — Compare one actual value (or callable) against one expected file:

golden_master.check(output, case / "expected.txt")
golden_master.check(data, case / "db.json", serializer=json.dumps)
golden_master.check(lambda: run(), case / "output.txt")

check_all(*actuals, directory, serializer=str) — Compare multiple values against result_0, result_1, ... files in a directory:

golden_master.check_all(*events, directory=case)
golden_master.check_all(lambda: run_command(cmd), directory=case)

Discovery functions

discover_test_cases(base_dir) — Find leaf directories (directories containing only files). Returns pytest.param objects with relative path IDs.

discover_test_files(base_dir, pattern) — Find files matching a glob pattern. Returns pytest.param objects with relative path IDs.

Behavior

• --remaster (default): When output doesn't match, the expected file is updated and the test fails with "please review and relaunch". Review the diff in git, then rerun.
• --no-remaster: When output doesn't match, the test fails with a unified diff. No files are modified.

The default can be changed in pyproject.toml:

[tool.pytest.ini_options]
remaster-by-default = false