conftest.py

r"""*pytest configuration for the* ``stdio_mgr`` *test suite*.

``stdio_mgr`` provides a context manager for convenient
mocking and/or wrapping of ``stdin``/``stdout``/``stderr``
interactions.

**Author**
    Brian Skinn (bskinn@alum.mit.edu)

**File Created**
    6 Feb 2019

**Copyright**
    \(c) Brian Skinn 2018-2019

**Source Repository**
    http://github.com/bskinn/stdio-mgr

**Documentation**
    See README.rst at the GitHub repository

**License**
    The MIT License; see |license_txt|_ for full license terms

**Members**

"""

import os
import sys
import warnings

import _pytest.warnings
import pytest

from stdio_mgr import stdio_mgr


@pytest.fixture(scope="session")
def warnings_are_errors(pytestconfig):
    """Provide concise access to '-W error::Warning' CLI option."""
    try:
        cmdline_filters = pytestconfig.getoption("pythonwarnings")
    except ValueError:
        return False

    # Explicit bool conversion to quiet pytest 'don't assert None' warning
    return bool(cmdline_filters and "error::Warning" in cmdline_filters)


@pytest.fixture
def check_warnings_plugin_enabled():
    """Check the warnings module is enabled."""
    # Check pytest was not invoked with -p no:warnings.
    try:
        impl = warnings._showwarnmsg_impl
    except AttributeError:
        # Python < 3.6
        impl = warnings.showwarning

    return impl.__name__ == "append"


@pytest.fixture
def enable_warnings_plugin(request):
    """Enable warnings for a single test."""
    assert check_warnings_plugin_enabled
    with _pytest.warnings.catch_warnings_for_item(
        config=request.config,
        ihook=request.node.ihook,
        when="runtest",
        item=request.node,
    ):
        yield


@pytest.fixture(autouse=True, scope="session")
def add_stdio_mgr(doctest_namespace):
    """Add stdio_mgr to doctest namespace."""
    doctest_namespace["stdio_mgr"] = stdio_mgr
    doctest_namespace["os"] = os


@pytest.fixture(scope="session")
def convert_newlines():
    """Supply platform-dependent newline transform function."""
    if sys.platform == "win32":
        return lambda s: s.replace("\n", "\r\n")
    else:
        return lambda s: s