# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt

"""
Pytest auto configuration.

This module is run automatically by pytest, to define and enable fixtures.
"""

import os
import sys
import sysconfig
import warnings
from pathlib import Path

import pytest

from coverage import env
from coverage.files import set_relative_directory

# Pytest will rewrite assertions in test modules, but not elsewhere.
# This tells pytest to also rewrite assertions in coveragetest.py.
pytest.register_assert_rewrite("tests.coveragetest")
pytest.register_assert_rewrite("tests.helpers")

# Pytest can take additional options:
# $set_env.py: PYTEST_ADDOPTS - Extra arguments to pytest.

pytest_plugins = "tests.balance_xdist_plugin"


@pytest.fixture(autouse=True)
def set_warnings():
    """Configure warnings to show while running tests."""
    warnings.simplefilter("default")
    warnings.simplefilter("once", DeprecationWarning)

    # Warnings to suppress:
    # How come these warnings are successfully suppressed here, but not in setup.cfg??

    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message=r".*imp module is deprecated in favour of importlib",
    )

    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message=r"module 'sre_constants' is deprecated",
    )

    warnings.filterwarnings(
        "ignore",
        category=pytest.PytestRemovedIn8Warning,
    )

    if env.PYPY:
        # pypy3 warns about unclosed files a lot.
        warnings.filterwarnings("ignore", r".*unclosed file", category=ResourceWarning)


@pytest.fixture(autouse=True)
def reset_sys_path():
    """Clean up sys.path changes around every test."""
    sys_path = list(sys.path)
    yield
    sys.path[:] = sys_path


@pytest.fixture(autouse=True)
def reset_environment():
    """Make sure a test setting an envvar doesn't leak into another test."""
    old_environ = os.environ.copy()
    yield
    os.environ.clear()
    os.environ.update(old_environ)


@pytest.fixture(autouse=True)
def reset_filesdotpy_globals():
    """coverage/files.py has some unfortunate globals. Reset them every test."""
    set_relative_directory()
    yield

WORKER = os.environ.get("PYTEST_XDIST_WORKER", "none")

def pytest_sessionstart():
    """Run once at the start of the test session."""
    # Only in the main process...
    if WORKER == "none":
        # Create a .pth file for measuring subprocess coverage.
        pth_dir = find_writable_pth_directory()
        assert pth_dir
        (pth_dir / "subcover.pth").write_text("import coverage; coverage.process_startup()\n")
        # subcover.pth is deleted by pytest_sessionfinish below.


def pytest_sessionfinish():
    """Hook the end of a test session, to clean up."""
    # This is called by each of the workers and by the main process.
    if WORKER == "none":
        for pth_dir in possible_pth_dirs():             # pragma: part covered
            pth_file = pth_dir / "subcover.pth"
            if pth_file.exists():
                pth_file.unlink()


def possible_pth_dirs():
    """Produce a sequence of directories for trying to write .pth files."""
    # First look through sys.path, and if we find a .pth file, then it's a good
    # place to put ours.
    for pth_dir in map(Path, sys.path):             # pragma: part covered
        pth_files = list(pth_dir.glob("*.pth"))
        if pth_files:
            yield pth_dir

    # If we're still looking, then try the Python library directory.
    # https://github.com/nedbat/coveragepy/issues/339
    yield Path(sysconfig.get_path("purelib"))       # pragma: cant happen


def find_writable_pth_directory():
    """Find a place to write a .pth file."""
    for pth_dir in possible_pth_dirs():             # pragma: part covered
        try_it = pth_dir / f"touch_{WORKER}.it"
        try:
            try_it.write_text("foo")
        except OSError:                             # pragma: cant happen
            continue

        os.remove(try_it)
        return pth_dir

    return None                                     # pragma: cant happen