pytest_test_categories.adapters.filesystem

Production filesystem blocker adapter using patching.

This module provides the production implementation of FilesystemBlockerPort that actually intercepts filesystem operations by patching builtins.open, pathlib.Path, os module functions, and shutil functions.

The FilesystemPatchingBlocker follows hexagonal architecture principles: - Implements the FilesystemBlockerPort interface (port) - Patches filesystem operations to intercept access attempts - Raises FilesystemAccessViolationError on unauthorized access - Restores original functions on deactivation

Example

>>> blocker = FilesystemPatchingBlocker()
>>> try:
...     blocker.activate(TestSize.SMALL, EnforcementMode.STRICT, frozenset())
...     # Any open() call will now be intercepted
... finally:
...     blocker.deactivate()  # Restore original filesystem behavior

See also

• FilesystemBlockerPort: The abstract interface in ports/filesystem.py

• FakeFilesystemBlocker: Test adapter in adapters/fake_filesystem.py

• SocketPatchingNetworkBlocker: Similar production adapter pattern for network

Attributes

OpenReturnType

Classes

FilesystemPatchingBlocker

Production adapter that patches filesystem operations to block access.

Module Contents

class pytest_test_categories.adapters.filesystem.FilesystemPatchingBlocker(/, **data)

Bases: pytest_test_categories.ports.filesystem.FilesystemBlockerPort

Production adapter that patches filesystem operations to block access.

This adapter intercepts filesystem access by patching: - builtins.open - pathlib.Path methods (read_text, write_text, read_bytes, write_bytes, etc.) - os module functions (remove, mkdir, makedirs, etc.) - shutil functions (copy, move, rmtree, etc.)

The patching is reversible - deactivate() restores the original functions.

Parameters:

data (Any)

state

Current blocker state (inherited from FilesystemBlockerPort).

current_test_size

The test size set during activation.

current_enforcement_mode

The enforcement mode set during activation.

current_allowed_paths

The allowed paths set during activation.

current_test_nodeid

The pytest node ID of the current test.

Warning

This adapter modifies global state (builtins.open). Always use in a try/finally block or context manager to ensure cleanup.

Example

>>> blocker = FilesystemPatchingBlocker()
>>> try:
...     blocker.activate(TestSize.SMALL, EnforcementMode.STRICT, frozenset())
...     open('/etc/passwd', 'r')  # Raises FilesystemAccessViolationError
... finally:
...     blocker.deactivate()

Create a new model by parsing and validating input data from keyword arguments.

Raises [ValidationError][pydantic_core.ValidationError] if the input data cannot be validated to form a valid model.

self is explicitly positional-only to allow self as a field name.

model_post_init(context, /)

Initialize post-Pydantic setup, storing reference to original functions.

Parameters:

context (object)

Return type:

None

reset()

Reset blocker to initial state, restoring original filesystem functions.

This is safe to call regardless of current state.

Return type:

None

current_allowed_paths: frozenset[pathlib.Path] = None

current_enforcement_mode: pytest_test_categories.ports.network.EnforcementMode | None = None

current_test_nodeid: str = None

current_test_size: pytest_test_categories.types.TestSize | None = None

pytest_test_categories.adapters.filesystem.OpenReturnType