Initial commit

.github/workflows/ci.yaml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        python_version: ["3.8", "3.9", "3.10", "3.11"]
+    runs-on: "ubuntu-latest"
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Python ${{ matrix.python_version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python_version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip wheel
+        python -m pip install tox==4.* tox-gh-actions==3.*
+    - name: Run tox
+      run: tox
+    - name: System test
+      run: ./tests/system_test/system_test.sh

.github/workflows/publish.yaml

@@ -0,0 +1,19 @@
+# Thanks to: Sean Hammond
+# https://www.seanh.cc/2022/05/21/publishing-python-packages-from-github-actions
+name: Publish to PyPI.org
+on:
+  release:
+    types: [published]
+jobs:
+  pypi:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - run: python3 -m pip install --upgrade build && python3 -m build
+      - name: Publish package
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          password: ${{ secrets.PYPI_API_TOKEN }}

.gitignore

@@ -157,4 +157,4 @@ cython_debug/
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
+.idea/

pyproject.toml

@@ -0,0 +1,130 @@
+[project]
+name = "pytest-litter"
+description = "Pytest plugin which verifies that tests do not modify file trees."
+# readme = "README.md"
+# license = {file = "LICENSE"}
+urls = {repo = "https://github.com/mam-dev/pytest-litter"}
+requires-python = ">=3.8"
+dependencies = ["pytest >= 6.1"]
+dynamic = ["version"]
+version = "0.0.1.dev0"
+classifiers = [
+  # "Development Status :: 5 - Production/Stable",
+  "Programming Language :: Python :: 3.9",
+  "Programming Language :: Python :: 3.10",
+  "Programming Language :: Python :: 3.11",
+  "Topic :: Software Development :: Testing",
+  "Topic :: Software Development :: Testing :: Unit",
+  "Framework :: Pytest",
+  "License :: OSI Approved :: Apache Software License",
+]
+
+[project.entry-points.pytest11]
+pytest-litter = "pytest_litter.plugin.plugin"
+
+[build-system]
+requires = ["setuptools>=51", "wheel", "setuptools_scm[toml]>=6.2"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools_scm]
+
+[tool.setuptools.packages.find]
+where = ["src"]
+namespaces = false
+
+[tool.pytest.ini_options]
+addopts = "--random-order -p no:pytest-litter -p pytester -vv"
+testpaths = ["tests"]
+pytester_example_dir = "tests/pytester"
+
+[tool.coverage.run]
+branch = true
+source_pkgs = ["pytest_litter"]
+
+[tool.coverage.report]
+show_missing = true
+fail_under = 100
+
+[tool.mypy]
+files = ["src", "tests"]
+warn_no_return = true
+warn_return_any = true
+warn_unused_configs = true
+warn_unused_ignores = true
+warn_redundant_casts = true
+warn_unreachable = true
+check_untyped_defs = true
+disallow_any_generics = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_untyped_decorators = true
+no_implicit_optional = true
+no_implicit_reexport = true
+strict_equality = true
+strict_concatenate = true
+
+[tool.ruff]
+src = ["src", "tests"]
+select = [
+  "E",   # pycodestyle
+  "F",   # pyflakes
+  "UP",  # pyupgrade
+  "S",   # flake8-bandit
+  "D",   # pydocstyle
+  "PT",  # flake8-pytest-style
+  "I",   # isort
+  "RUF", # Ruff-specific rules
+  "PTH", # flake8-use-pathlib
+  "ERA", # eradicate
+  "PL",  # pylint
+  "FBT", # flake8-boolean-trap
+  "B",   # flake8-bugbear
+  "A",   # flake8-builtins
+  "ISC", # flake8-implicit-str-concat
+  "INP", # flake8-no-pep420
+  "SLF", # flake8-self
+  "SIM", # flake8-simplify
+  "TID", # flake8-tidy-imports
+  "ARG", # flake8-unused-arguments
+  "TRY", # tryceratops
+  "FLY",  # flynt
+  "RSE",  # flake8-raise
+  "RET",  # flake8-return
+  "FIX",  # flake8-fixme
+  "Q",    # flake8-quotes
+  "C4",   # flake8-comprehensions
+  "DTZ",  # flake8-datetimez
+  "T10",  # flake8-debugger
+  "T20",  # flake8-print
+  "TCH",  # flake8-type-checking
+]
+ignore = [
+  "D100", "D102", "D103", "D104", "D105", "D107",
+  "PTH123",
+  "TRY003", "TRY301",
+]
+
+[tool.ruff.per-file-ignores]
+"tests/**/*.py" = [
+  "S101", "S105",
+  "D103",
+  "FBT001",
+  "SLF001",
+  "PLR2004", "PLR0913",
+  "ARG001",
+  "INP001",
+]
+
+[tool.ruff.pydocstyle]
+convention = "google"
+
+[tool.ruff.flake8-pytest-style]
+fixture-parentheses = false
+mark-parentheses = false
+parametrize-names-type = "csv"
+parametrize-values-type = "list"
+
+[tool.ruff.flake8-tidy-imports]
+ban-relative-imports = "parents"

requirements-lint.txt

@@ -0,0 +1,3 @@
+ruff
+black
+mypy

requirements-test.txt

@@ -0,0 +1,4 @@
+pytest
+coverage>=5.3
+pytest-random-order
+pytest-integration

src/pytest_litter/__init__.py

@@ -0,0 +1 @@
+"""Pytest plugin which verifies that tests do not modify file trees."""

src/pytest_litter/plugin/__init__.py

@@ -0,0 +1 @@
+"""Pytest plugin code."""

src/pytest_litter/plugin/plugin.py

@@ -0,0 +1,44 @@
+"""Pytest plugin code."""
+
+from typing import Optional
+
+import pytest
+
+from pytest_litter.plugin.utils import (
+    COMPARATOR_KEY,
+    SNAPSHOT_KEY,
+    raise_test_error_from_comparison,
+    run_snapshot_comparison,
+)
+from pytest_litter.snapshots import (
+    DirectoryIgnoreSpec,
+    IgnoreSpec,
+    RegexIgnoreSpec,
+    SnapshotComparator,
+    TreeSnapshot,
+)
+
+
+def pytest_configure(config: pytest.Config) -> None:
+    """Configure pytest-litter plugin (pytest hook function)."""
+    ignore_specs: list[IgnoreSpec] = []
+    basetemp: Optional[str] = config.getoption("basetemp", None)
+    if basetemp is not None:
+        ignore_specs.append(
+            DirectoryIgnoreSpec(
+                directory=config.rootpath / basetemp,
+            )
+        )
+    ignore_specs.append(RegexIgnoreSpec(regex=r".*/__pycache__.*"))
+    config.stash[SNAPSHOT_KEY] = TreeSnapshot(root=config.rootpath)
+    config.stash[COMPARATOR_KEY] = SnapshotComparator(ignore_specs=ignore_specs)
+
+
+@pytest.hookimpl(hookwrapper=True)  # type: ignore[misc]
+def pytest_runtest_call(item: pytest.Item):  # type: ignore[no-untyped-def]
+    yield
+    run_snapshot_comparison(
+        test_name=item.name,
+        config=item.config,
+        mismatch_cb=raise_test_error_from_comparison,
+    )

src/pytest_litter/plugin/utils.py

@@ -0,0 +1,59 @@
+from pathlib import Path
+from typing import Callable, Iterable
+
+import pytest
+
+from pytest_litter.snapshots import SnapshotComparator, SnapshotComparison, TreeSnapshot
+
+SNAPSHOT_KEY = pytest.StashKey[TreeSnapshot]()
+COMPARATOR_KEY = pytest.StashKey[SnapshotComparator]()
+
+
+class ProblematicTestLitterError(Exception):
+    """Raised when a test causes littering, i.e., modifies file tree."""
+
+
+def format_test_snapshot_mismatch_message(
+    test_name: str, paths_added: Iterable[Path], paths_deleted: Iterable[Path]
+) -> str:
+    def _iterable_to_human_readable(iterable: Iterable[Path]) -> str:
+        return ", ".join(f"'{x}'" for x in iterable)
+
+    message = f"The test '{test_name}'"
+    if paths_added:
+        message += f" added {_iterable_to_human_readable(paths_added)}"
+        if paths_deleted:
+            message += " and"
+    if paths_deleted:
+        message += f" deleted {_iterable_to_human_readable(paths_deleted)}"
+    return message
+
+
+def raise_test_error_from_comparison(
+    test_name: str, comparison: SnapshotComparison
+) -> None:
+    """Raise ProblematicTestLitterError for test_name based on comparison."""
+    raise ProblematicTestLitterError(
+        format_test_snapshot_mismatch_message(
+            test_name=test_name,
+            paths_added=tuple(p.path for p in comparison.only_b),
+            paths_deleted=tuple(p.path for p in comparison.only_a),
+        )
+    )
+
+
+def run_snapshot_comparison(
+    test_name: str,
+    config: pytest.Config,
+    mismatch_cb: Callable[[str, SnapshotComparison], None],
+) -> None:
+    """Compare current and old snapshots and call mismatch_cb if there is a mismatch."""
+    original_snapshot: TreeSnapshot = config.stash[SNAPSHOT_KEY]
+    new_snapshot: TreeSnapshot = TreeSnapshot(root=original_snapshot.root)
+    config.stash[SNAPSHOT_KEY] = new_snapshot
+
+    comparator: SnapshotComparator = config.stash[COMPARATOR_KEY]
+    comparison: SnapshotComparison = comparator.compare(original_snapshot, new_snapshot)
+
+    if not comparison.matches:
+        mismatch_cb(test_name, comparison)