test_capture.py

import contextlib
import io
import os
import subprocess
import sys
import textwrap
from io import UnsupportedOperation
from typing import BinaryIO
from typing import cast
from typing import Generator
from typing import TextIO

import pytest
from _pytest import capture
from _pytest.capture import _get_multicapture
from _pytest.capture import CaptureManager
from _pytest.capture import CaptureResult
from _pytest.capture import MultiCapture
from _pytest.config import ExitCode
from _pytest.pytester import Testdir

# note: py.io capture tests where copied from
# pylib 1.4.20.dev2 (rev 13d9af95547e)


def StdCaptureFD(
    out: bool = True, err: bool = True, in_: bool = True
) -> MultiCapture[str]:
    return capture.MultiCapture(
        in_=capture.FDCapture(0) if in_ else None,
        out=capture.FDCapture(1) if out else None,
        err=capture.FDCapture(2) if err else None,
    )


def StdCapture(
    out: bool = True, err: bool = True, in_: bool = True
) -> MultiCapture[str]:
    return capture.MultiCapture(
        in_=capture.SysCapture(0) if in_ else None,
        out=capture.SysCapture(1) if out else None,
        err=capture.SysCapture(2) if err else None,
    )


def TeeStdCapture(
    out: bool = True, err: bool = True, in_: bool = True
) -> MultiCapture[str]:
    return capture.MultiCapture(
        in_=capture.SysCapture(0, tee=True) if in_ else None,
        out=capture.SysCapture(1, tee=True) if out else None,
        err=capture.SysCapture(2, tee=True) if err else None,
    )


class TestCaptureManager:
    @pytest.mark.parametrize("method", ["no", "sys", "fd"])
    def test_capturing_basic_api(self, method):
        capouter = StdCaptureFD()
        old = sys.stdout, sys.stderr, sys.stdin
        try:
            capman = CaptureManager(method)
            capman.start_global_capturing()
            capman.suspend_global_capture()
            outerr = capman.read_global_capture()
            assert outerr == ("", "")
            capman.suspend_global_capture()
            outerr = capman.read_global_capture()
            assert outerr == ("", "")
            print("hello")
            capman.suspend_global_capture()
            out, err = capman.read_global_capture()
            if method == "no":
                assert old == (sys.stdout, sys.stderr, sys.stdin)
            else:
                assert not out
            capman.resume_global_capture()
            print("hello")
            capman.suspend_global_capture()
            out, err = capman.read_global_capture()
            if method != "no":
                assert out == "hello\n"
            capman.stop_global_capturing()
        finally:
            capouter.stop_capturing()

    def test_init_capturing(self):
        capouter = StdCaptureFD()
        try:
            capman = CaptureManager("fd")
            capman.start_global_capturing()
            pytest.raises(AssertionError, capman.start_global_capturing)
            capman.stop_global_capturing()
        finally:
            capouter.stop_capturing()


@pytest.mark.parametrize("method", ["fd", "sys"])
def test_capturing_unicode(testdir, method):
    obj = "'b\u00f6y'"
    testdir.makepyfile(
        """\
        # taken from issue 227 from nosetests
        def test_unicode():
            import sys
            print(sys.stdout)
            print(%s)
        """
        % obj
    )
    result = testdir.runpytest("--capture=%s" % method)
    result.stdout.fnmatch_lines(["*1 passed*"])


@pytest.mark.parametrize("method", ["fd", "sys"])
def test_capturing_bytes_in_utf8_encoding(testdir, method):
    testdir.makepyfile(
        """\
        def test_unicode():
            print('b\\u00f6y')
        """
    )
    result = testdir.runpytest("--capture=%s" % method)
    result.stdout.fnmatch_lines(["*1 passed*"])


def test_collect_capturing(testdir):
    p = testdir.makepyfile(
        """
        import sys

        print("collect %s failure" % 13)
        sys.stderr.write("collect %s_stderr failure" % 13)
        import xyz42123
    """
    )
    result = testdir.runpytest(p)
    result.stdout.fnmatch_lines(
        [
            "*Captured stdout*",
            "collect 13 failure",
            "*Captured stderr*",
            "collect 13_stderr failure",
        ]
    )


class TestPerTestCapturing:
    def test_capture_and_fixtures(self, testdir):
        p = testdir.makepyfile(
            """
            def setup_module(mod):
                print("setup module")
            def setup_function(function):
                print("setup " + function.__name__)
            def test_func1():
                print("in func1")
                assert 0
            def test_func2():
                print("in func2")
                assert 0
        """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            [
                "setup module*",
                "setup test_func1*",
                "in func1*",
                "setup test_func2*",
                "in func2*",
            ]
        )

    @pytest.mark.xfail(reason="unimplemented feature")
    def test_capture_scope_cache(self, testdir):
        p = testdir.makepyfile(
            """
            import sys
            def setup_module(func):
                print("module-setup")
            def setup_function(func):
                print("function-setup")
            def test_func():
                print("in function")
                assert 0
            def teardown_function(func):
                print("in teardown")
        """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            [
                "*test_func():*",
                "*Captured stdout during setup*",
                "module-setup*",
                "function-setup*",
                "*Captured stdout*",
                "in teardown*",
            ]
        )

    def test_no_carry_over(self, testdir):
        p = testdir.makepyfile(
            """
            def test_func1():
                print("in func1")
            def test_func2():
                print("in func2")
                assert 0
        """
        )
        result = testdir.runpytest(p)
        s = result.stdout.str()
        assert "in func1" not in s
        assert "in func2" in s

    def test_teardown_capturing(self, testdir):
        p = testdir.makepyfile(
            """
            def setup_function(function):
                print("setup func1")
            def teardown_function(function):
                print("teardown func1")
                assert 0
            def test_func1():
                print("in func1")
                pass
        """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            [
                "*teardown_function*",
                "*Captured stdout*",
                "setup func1*",
                "in func1*",
                "teardown func1*",
                # "*1 fixture failure*"
            ]
        )

    def test_teardown_capturing_final(self, testdir):
        p = testdir.makepyfile(
            """
            def teardown_module(mod):
                print("teardown module")
                assert 0
            def test_func():
                pass
        """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            [
                "*def teardown_module(mod):*",
                "*Captured stdout*",
                "*teardown module*",
                "*1 error*",
            ]
        )

    def test_capturing_outerr(self, testdir):
        p1 = testdir.makepyfile(
            """\
            import sys
            def test_capturing():
                print(42)
                sys.stderr.write(str(23))
            def test_capturing_error():
                print(1)
                sys.stderr.write(str(2))
                raise ValueError
            """
        )
        result = testdir.runpytest(p1)
        result.stdout.fnmatch_lines(
            [
                "*test_capturing_outerr.py .F*",
                "====* FAILURES *====",
                "____*____",
                "*test_capturing_outerr.py:8: ValueError",
                "*--- Captured stdout *call*",
                "1",
                "*--- Captured stderr *call*",
                "2",
            ]
        )


class TestLoggingInteraction:
    def test_logging_stream_ownership(self, testdir):
        p = testdir.makepyfile(
            """\
            def test_logging():
                import logging
                import pytest
                stream = capture.CaptureIO()
                logging.basicConfig(stream=stream)
                stream.close() # to free memory/release resources
            """
        )
        result = testdir.runpytest_subprocess(p)
        assert result.stderr.str().find("atexit") == -1

    def test_logging_and_immediate_setupteardown(self, testdir):
        p = testdir.makepyfile(
            """\
            import logging
            def setup_function(function):
                logging.warning("hello1")

            def test_logging():
                logging.warning("hello2")
                assert 0

            def teardown_function(function):
                logging.warning("hello3")
                assert 0
            """
        )
        for optargs in (("--capture=sys",), ("--capture=fd",)):
            print(optargs)
            result = testdir.runpytest_subprocess(p, *optargs)
            s = result.stdout.str()
            result.stdout.fnmatch_lines(
                ["*WARN*hello3", "*WARN*hello1", "*WARN*hello2"]  # errors show first!
            )
            # verify proper termination
            assert "closed" not in s

    def test_logging_and_crossscope_fixtures(self, testdir):
        p = testdir.makepyfile(
            """\
            import logging
            def setup_module(function):
                logging.warning("hello1")

            def test_logging():
                logging.warning("hello2")
                assert 0

            def teardown_module(function):
                logging.warning("hello3")
                assert 0
            """
        )
        for optargs in (("--capture=sys",), ("--capture=fd",)):
            print(optargs)
            result = testdir.runpytest_subprocess(p, *optargs)
            s = result.stdout.str()
            result.stdout.fnmatch_lines(
                ["*WARN*hello3", "*WARN*hello1", "*WARN*hello2"]  # errors come first
            )
            # verify proper termination
            assert "closed" not in s

    def test_conftestlogging_is_shown(self, testdir):
        testdir.makeconftest(
            """\
                import logging
                logging.basicConfig()
                logging.warning("hello435")
            """
        )
        # make sure that logging is still captured in tests
        result = testdir.runpytest_subprocess("-s", "-p", "no:capturelog")
        assert result.ret == ExitCode.NO_TESTS_COLLECTED
        result.stderr.fnmatch_lines(["WARNING*hello435*"])
        assert "operation on closed file" not in result.stderr.str()

    def test_conftestlogging_and_test_logging(self, testdir):
        testdir.makeconftest(
            """\
                import logging
                logging.basicConfig()
            """
        )
        # make sure that logging is still captured in tests
        p = testdir.makepyfile(
            """\
            def test_hello():
                import logging
                logging.warning("hello433")
                assert 0
            """
        )
        result = testdir.runpytest_subprocess(p, "-p", "no:capturelog")
        assert result.ret != 0
        result.stdout.fnmatch_lines(["WARNING*hello433*"])
        assert "something" not in result.stderr.str()
        assert "operation on closed file" not in result.stderr.str()

    def test_logging_after_cap_stopped(self, testdir):
        testdir.makeconftest(
            """\
                import pytest
                import logging

                log = logging.getLogger(__name__)

                @pytest.fixture
                def log_on_teardown():
                    yield
                    log.warning('Logging on teardown')
            """
        )
        # make sure that logging is still captured in tests
        p = testdir.makepyfile(
            """\
            def test_hello(log_on_teardown):
                import logging
                logging.warning("hello433")
                assert 1
                raise KeyboardInterrupt()
            """
        )
        result = testdir.runpytest_subprocess(p, "--log-cli-level", "info")
        assert result.ret != 0
        result.stdout.fnmatch_lines(
            ["*WARNING*hello433*", "*WARNING*Logging on teardown*"]
        )
        assert (
            "AttributeError: 'NoneType' object has no attribute 'resume_capturing'"
            not in result.stderr.str()
        )


class TestCaptureFixture:
    @pytest.mark.parametrize("opt", [[], ["-s"]])
    def test_std_functional(self, testdir, opt):
        reprec = testdir.inline_runsource(
            """\
            def test_hello(capsys):
                print(42)
                out, err = capsys.readouterr()
                assert out.startswith("42")
            """,
            *opt,
        )
        reprec.assertoutcome(passed=1)

    def test_capsyscapfd(self, testdir):
        p = testdir.makepyfile(
            """\
            def test_one(capsys, capfd):
                pass
            def test_two(capfd, capsys):
                pass
            """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            [
                "*ERROR*setup*test_one*",
                "E*capfd*capsys*same*time*",
                "*ERROR*setup*test_two*",
                "E*capsys*capfd*same*time*",
                "*2 errors*",
            ]
        )

    def test_capturing_getfixturevalue(self, testdir):
        """Test that asking for "capfd" and "capsys" using request.getfixturevalue
        in the same test is an error.
        """
        testdir.makepyfile(
            """\
            def test_one(capsys, request):
                request.getfixturevalue("capfd")
            def test_two(capfd, request):
                request.getfixturevalue("capsys")
            """
        )
        result = testdir.runpytest()
        result.stdout.fnmatch_lines(
            [
                "*test_one*",
                "E * cannot use capfd and capsys at the same time",
                "*test_two*",
                "E * cannot use capsys and capfd at the same time",
                "*2 failed in*",
            ]
        )

    def test_capsyscapfdbinary(self, testdir):
        p = testdir.makepyfile(
            """\
            def test_one(capsys, capfdbinary):
                pass
            """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(
            ["*ERROR*setup*test_one*", "E*capfdbinary*capsys*same*time*", "*1 error*"]
        )

    @pytest.mark.parametrize("method", ["sys", "fd"])
    def test_capture_is_represented_on_failure_issue128(self, testdir, method):
        p = testdir.makepyfile(
            """\
            def test_hello(cap{}):
                print("xxx42xxx")
                assert 0
            """.format(
                method
            )
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(["xxx42xxx"])

    def test_stdfd_functional(self, testdir):
        reprec = testdir.inline_runsource(
            """\
            def test_hello(capfd):
                import os
                os.write(1, b"42")
                out, err = capfd.readouterr()
                assert out.startswith("42")
                capfd.close()
            """
        )
        reprec.assertoutcome(passed=1)

    @pytest.mark.parametrize("nl", ("\n", "\r\n", "\r"))
    def test_cafd_preserves_newlines(self, capfd, nl):
        print("test", end=nl)
        out, err = capfd.readouterr()
        assert out.endswith(nl)

    def test_capfdbinary(self, testdir):
        reprec = testdir.inline_runsource(
            """\
            def test_hello(capfdbinary):
                import os
                # some likely un-decodable bytes
                os.write(1, b'\\xfe\\x98\\x20')
                out, err = capfdbinary.readouterr()
                assert out == b'\\xfe\\x98\\x20'
                assert err == b''
            """
        )
        reprec.assertoutcome(passed=1)

    def test_capsysbinary(self, testdir):
        p1 = testdir.makepyfile(
            r"""
            def test_hello(capsysbinary):
                import sys

                sys.stdout.buffer.write(b'hello')

                # Some likely un-decodable bytes.
                sys.stdout.buffer.write(b'\xfe\x98\x20')

                sys.stdout.buffer.flush()

                # Ensure writing in text mode still works and is captured.
                # https://github.com/pytest-dev/pytest/issues/6871
                print("world", flush=True)

                out, err = capsysbinary.readouterr()
                assert out == b'hello\xfe\x98\x20world\n'
                assert err == b''

                print("stdout after")
                print("stderr after", file=sys.stderr)
            """
        )
        result = testdir.runpytest(str(p1), "-rA")
        result.stdout.fnmatch_lines(
            [
                "*- Captured stdout call -*",
                "stdout after",
                "*- Captured stderr call -*",
                "stderr after",
                "*= 1 passed in *",
            ]
        )

    def test_partial_setup_failure(self, testdir):
        p = testdir.makepyfile(
            """\
            def test_hello(capsys, missingarg):
                pass
            """
        )
        result = testdir.runpytest(p)
        result.stdout.fnmatch_lines(["*test_partial_setup_failure*", "*1 error*"])

    def test_keyboardinterrupt_disables_capturing(self, testdir):
        p = testdir.makepyfile(
            """\
            def test_hello(capfd):
                import os
                os.write(1, b'42')
                raise KeyboardInterrupt()
            """
        )
        result = testdir.runpytest_subprocess(p)
        result.stdout.fnmatch_lines(["*KeyboardInterrupt*"])
        assert result.ret == 2

    def test_capture_and_logging(self, testdir):
        """#14"""
        p = testdir.makepyfile(
            """\
            import logging
            def test_log(capsys):
                logging.error('x')
            """
        )
        result = testdir.runpytest_subprocess(p)
        assert "closed" not in result.stderr.str()

    @pytest.mark.parametrize("fixture", ["capsys", "capfd"])
    @pytest.mark.parametrize("no_capture", [True, False])
    def test_disabled_capture_fixture(self, testdir, fixture, no_capture):
        testdir.makepyfile(
            """\
            def test_disabled({fixture}):
                print('captured before')
                with {fixture}.disabled():
                    print('while capture is disabled')
                print('captured after')
                assert {fixture}.readouterr() == ('captured before\\ncaptured after\\n', '')

            def test_normal():
                print('test_normal executed')
        """.format(
                fixture=fixture
            )
        )
        args = ("-s",) if no_capture else ()
        result = testdir.runpytest_subprocess(*args)
        result.stdout.fnmatch_lines(["*while capture is disabled*", "*= 2 passed in *"])
        result.stdout.no_fnmatch_line("*captured before*")
        result.stdout.no_fnmatch_line("*captured after*")
        if no_capture:
            assert "test_normal executed" in result.stdout.str()
        else:
            result.stdout.no_fnmatch_line("*test_normal executed*")

    def test_disabled_capture_fixture_twice(self, testdir: Testdir) -> None:
        """Test that an inner disabled() exit doesn't undo an outer disabled().

        Issue #7148.
        """
        testdir.makepyfile(
            """
            def test_disabled(capfd):
                print('captured before')
                with capfd.disabled():
                    print('while capture is disabled 1')
                    with capfd.disabled():
                        print('while capture is disabled 2')
                    print('while capture is disabled 1 after')
                print('captured after')
                assert capfd.readouterr() == ('captured before\\ncaptured after\\n', '')
        """
        )
        result = testdir.runpytest_subprocess()
        result.stdout.fnmatch_lines(
            [
                "*while capture is disabled 1",
                "*while capture is disabled 2",
                "*while capture is disabled 1 after",
            ],
            consecutive=True,
        )

    @pytest.mark.parametrize("fixture", ["capsys", "capfd"])
    def test_fixture_use_by_other_fixtures(self, testdir, fixture):
        """Ensure that capsys and capfd can be used by other fixtures during
        setup and teardown."""
        testdir.makepyfile(
            """\
            import sys
            import pytest

            @pytest.fixture
            def captured_print({fixture}):
                print('stdout contents begin')
                print('stderr contents begin', file=sys.stderr)
                out, err = {fixture}.readouterr()

                yield out, err

                print('stdout contents end')
                print('stderr contents end', file=sys.stderr)
                out, err = {fixture}.readouterr()
                assert out == 'stdout contents end\\n'
                assert err == 'stderr contents end\\n'

            def test_captured_print(captured_print):
                out, err = captured_print
                assert out == 'stdout contents begin\\n'
                assert err == 'stderr contents begin\\n'
        """.format(
                fixture=fixture
            )
        )
        result = testdir.runpytest_subprocess()
        result.stdout.fnmatch_lines(["*1 passed*"])
        result.stdout.no_fnmatch_line("*stdout contents begin*")
        result.stdout.no_fnmatch_line("*stderr contents begin*")

    @pytest.mark.parametrize("cap", ["capsys", "capfd"])
    def test_fixture_use_by_other_fixtures_teardown(self, testdir, cap):
        """Ensure we can access setup and teardown buffers from teardown when using capsys/capfd (##3033)"""
        testdir.makepyfile(
            """\
            import sys
            import pytest
            import os

            @pytest.fixture()
            def fix({cap}):
                print("setup out")
                sys.stderr.write("setup err\\n")
                yield
                out, err = {cap}.readouterr()
                assert out == 'setup out\\ncall out\\n'
                assert err == 'setup err\\ncall err\\n'

            def test_a(fix):
                print("call out")
                sys.stderr.write("call err\\n")
        """.format(
                cap=cap
            )
        )
        reprec = testdir.inline_run()
        reprec.assertoutcome(passed=1)


def test_setup_failure_does_not_kill_capturing(testdir):
    sub1 = testdir.mkpydir("sub1")
    sub1.join("conftest.py").write(
        textwrap.dedent(
            """\
            def pytest_runtest_setup(item):
                raise ValueError(42)
            """
        )
    )
    sub1.join("test_mod.py").write("def test_func1(): pass")
    result = testdir.runpytest(testdir.tmpdir, "--traceconfig")
    result.stdout.fnmatch_lines(["*ValueError(42)*", "*1 error*"])


def test_capture_conftest_runtest_setup(testdir):
    testdir.makeconftest(
        """
        def pytest_runtest_setup():
            print("hello19")
    """
    )
    testdir.makepyfile("def test_func(): pass")
    result = testdir.runpytest()
    assert result.ret == 0
    result.stdout.no_fnmatch_line("*hello19*")


def test_capture_badoutput_issue412(testdir):
    testdir.makepyfile(
        """
        import os

        def test_func():
            omg = bytearray([1,129,1])
            os.write(1, omg)
            assert 0
        """
    )
    result = testdir.runpytest("--capture=fd")
    result.stdout.fnmatch_lines(
        """
        *def test_func*
        *assert 0*
        *Captured*
        *1 failed*
    """
    )


def test_capture_early_option_parsing(testdir):
    testdir.makeconftest(
        """
        def pytest_runtest_setup():
            print("hello19")
    """
    )
    testdir.makepyfile("def test_func(): pass")
    result = testdir.runpytest("-vs")
    assert result.ret == 0
    assert "hello19" in result.stdout.str()


def test_capture_binary_output(testdir):
    testdir.makepyfile(
        r"""
        import pytest

        def test_a():
            import sys
            import subprocess
            subprocess.call([sys.executable, __file__])

        def test_foo():
            import os;os.write(1, b'\xc3')

        if __name__ == '__main__':
            test_foo()
        """
    )
    result = testdir.runpytest("--assert=plain")
    result.assert_outcomes(passed=2)


def test_error_during_readouterr(testdir):
    """Make sure we suspend capturing if errors occur during readouterr"""
    testdir.makepyfile(
        pytest_xyz="""
        from _pytest.capture import FDCapture

        def bad_snap(self):
            raise Exception('boom')

        assert FDCapture.snap
        FDCapture.snap = bad_snap
    """
    )
    result = testdir.runpytest_subprocess("-p", "pytest_xyz", "--version")
    result.stderr.fnmatch_lines(
        ["*in bad_snap", "    raise Exception('boom')", "Exception: boom"]
    )


class TestCaptureIO:
    def test_text(self):
        f = capture.CaptureIO()
        f.write("hello")
        s = f.getvalue()
        assert s == "hello"
        f.close()

    def test_unicode_and_str_mixture(self):
        f = capture.CaptureIO()
        f.write("\u00f6")
        pytest.raises(TypeError, f.write, b"hello")

    def test_write_bytes_to_buffer(self):
        """In python3, stdout / stderr are text io wrappers (exposing a buffer
        property of the underlying bytestream).  See issue #1407
        """
        f = capture.CaptureIO()
        f.buffer.write(b"foo\r\n")
        assert f.getvalue() == "foo\r\n"


class TestTeeCaptureIO(TestCaptureIO):
    def test_text(self):
        sio = io.StringIO()
        f = capture.TeeCaptureIO(sio)
        f.write("hello")
        s1 = f.getvalue()
        assert s1 == "hello"
        s2 = sio.getvalue()
        assert s2 == s1
        f.close()
        sio.close()

    def test_unicode_and_str_mixture(self):
        sio = io.StringIO()
        f = capture.TeeCaptureIO(sio)
        f.write("\u00f6")
        pytest.raises(TypeError, f.write, b"hello")


def test_dontreadfrominput():
    from _pytest.capture import DontReadFromInput

    f = DontReadFromInput()
    assert f.buffer is f
    assert not f.isatty()
    pytest.raises(OSError, f.read)
    pytest.raises(OSError, f.readlines)
    iter_f = iter(f)
    pytest.raises(OSError, next, iter_f)
    pytest.raises(UnsupportedOperation, f.fileno)
    f.close()  # just for completeness


def test_captureresult() -> None:
    cr = CaptureResult("out", "err")
    assert len(cr) == 2
    assert cr.out == "out"
    assert cr.err == "err"
    out, err = cr
    assert out == "out"
    assert err == "err"
    assert cr[0] == "out"
    assert cr[1] == "err"
    assert cr == cr
    assert cr == CaptureResult("out", "err")
    assert cr != CaptureResult("wrong", "err")
    assert cr == ("out", "err")
    assert cr != ("out", "wrong")
    assert hash(cr) == hash(CaptureResult("out", "err"))
    assert hash(cr) == hash(("out", "err"))
    assert hash(cr) != hash(("out", "wrong"))
    assert cr < ("z",)
    assert cr < ("z", "b")
    assert cr < ("z", "b", "c")
    assert cr.count("err") == 1
    assert cr.count("wrong") == 0
    assert cr.index("err") == 1
    with pytest.raises(ValueError):
        assert cr.index("wrong") == 0
    assert next(iter(cr)) == "out"
    assert cr._replace(err="replaced") == ("out", "replaced")


@pytest.fixture
def tmpfile(testdir) -> Generator[BinaryIO, None, None]:
    f = testdir.makepyfile("").open("wb+")
    yield f
    if not f.closed:
        f.close()


@contextlib.contextmanager
def lsof_check():
    pid = os.getpid()
    try:
        out = subprocess.check_output(("lsof", "-p", str(pid))).decode()
    except (OSError, subprocess.CalledProcessError, UnicodeDecodeError) as exc:
        # about UnicodeDecodeError, see note on pytester
        pytest.skip("could not run 'lsof' ({!r})".format(exc))
    yield
    out2 = subprocess.check_output(("lsof", "-p", str(pid))).decode()
    len1 = len([x for x in out.split("\n") if "REG" in x])
    len2 = len([x for x in out2.split("\n") if "REG" in x])
    assert len2 < len1 + 3, out2


class TestFDCapture:
    def test_simple(self, tmpfile):
        fd = tmpfile.fileno()
        cap = capture.FDCapture(fd)
        data = b"hello"
        os.write(fd, data)
        pytest.raises(AssertionError, cap.snap)
        cap.done()
        cap = capture.FDCapture(fd)
        cap.start()
        os.write(fd, data)
        s = cap.snap()
        cap.done()
        assert s == "hello"

    def test_simple_many(self, tmpfile):
        for i in range(10):
            self.test_simple(tmpfile)

    def test_simple_many_check_open_files(self, testdir):
        with lsof_check():
            with testdir.makepyfile("").open("wb+") as tmpfile:
                self.test_simple_many(tmpfile)

    def test_simple_fail_second_start(self, tmpfile):
        fd = tmpfile.fileno()
        cap = capture.FDCapture(fd)
        cap.done()
        pytest.raises(AssertionError, cap.start)

    def test_stderr(self):
        cap = capture.FDCapture(2)
        cap.start()
        print("hello", file=sys.stderr)
        s = cap.snap()
        cap.done()
        assert s == "hello\n"

    def test_stdin(self):
        cap = capture.FDCapture(0)
        cap.start()
        x = os.read(0, 100).strip()
        cap.done()
        assert x == b""

    def test_writeorg(self, tmpfile):
        data1, data2 = b"foo", b"bar"
        cap = capture.FDCapture(tmpfile.fileno())
        cap.start()
        tmpfile.write(data1)
        tmpfile.flush()
        cap.writeorg(data2.decode("ascii"))
        scap = cap.snap()
        cap.done()
        assert scap == data1.decode("ascii")
        with open(tmpfile.name, "rb") as stmp_file:
            stmp = stmp_file.read()
            assert stmp == data2

    def test_simple_resume_suspend(self):
        with saved_fd(1):
            cap = capture.FDCapture(1)
            cap.start()
            data = b"hello"
            os.write(1, data)
            sys.stdout.write("whatever")
            s = cap.snap()
            assert s == "hellowhatever"
            cap.suspend()
            os.write(1, b"world")
            sys.stdout.write("qlwkej")
            assert not cap.snap()
            cap.resume()
            os.write(1, b"but now")
            sys.stdout.write(" yes\n")
            s = cap.snap()
            assert s == "but now yes\n"
            cap.suspend()
            cap.done()
            pytest.raises(AssertionError, cap.suspend)

            assert repr(cap) == (
                "<FDCapture 1 oldfd={} _state='done' tmpfile={!r}>".format(
                    cap.targetfd_save, cap.tmpfile
                )
            )
            # Should not crash with missing "_old".
            assert repr(cap.syscapture) == (
                "<SysCapture stdout _old=<UNSET> _state='done' tmpfile={!r}>".format(
                    cap.syscapture.tmpfile
                )
            )

    def test_capfd_sys_stdout_mode(self, capfd):
        assert "b" not in sys.stdout.mode


@contextlib.contextmanager
def saved_fd(fd):
    new_fd = os.dup(fd)
    try:
        yield
    finally:
        os.dup2(new_fd, fd)
        os.close(new_fd)


class TestStdCapture:
    captureclass = staticmethod(StdCapture)

    @contextlib.contextmanager
    def getcapture(self, **kw):
        cap = self.__class__.captureclass(**kw)
        cap.start_capturing()
        try:
            yield cap
        finally:
            cap.stop_capturing()

    def test_capturing_done_simple(self):
        with self.getcapture() as cap:
            sys.stdout.write("hello")
            sys.stderr.write("world")
            out, err = cap.readouterr()
        assert out == "hello"
        assert err == "world"

    def test_capturing_reset_simple(self):
        with self.getcapture() as cap:
            print("hello world")
            sys.stderr.write("hello error\n")
            out, err = cap.readouterr()
        assert out == "hello world\n"
        assert err == "hello error\n"

    def test_capturing_readouterr(self):
        with self.getcapture() as cap:
            print("hello world")
            sys.stderr.write("hello error\n")
            out, err = cap.readouterr()
            assert out == "hello world\n"
            assert err == "hello error\n"
            sys.stderr.write("error2")
            out, err = cap.readouterr()
        assert err == "error2"

    def test_capture_results_accessible_by_attribute(self):
        with self.getcapture() as cap:
            sys.stdout.write("hello")
            sys.stderr.write("world")
            capture_result = cap.readouterr()
        assert capture_result.out == "hello"
        assert capture_result.err == "world"

    def test_capturing_readouterr_unicode(self):
        with self.getcapture() as cap:
            print("hxąć")
            out, err = cap.readouterr()
        assert out == "hxąć\n"

    def test_reset_twice_error(self):
        with self.getcapture() as cap:
            print("hello")
            out, err = cap.readouterr()
        pytest.raises(ValueError, cap.stop_capturing)
        assert out == "hello\n"
        assert not err

    def test_capturing_modify_sysouterr_in_between(self):
        oldout = sys.stdout
        olderr = sys.stderr
        with self.getcapture() as cap:
            sys.stdout.write("hello")
            sys.stderr.write("world")
            sys.stdout = capture.CaptureIO()
            sys.stderr = capture.CaptureIO()
            print("not seen")
            sys.stderr.write("not seen\n")
            out, err = cap.readouterr()
        assert out == "hello"
        assert err == "world"
        assert sys.stdout == oldout
        assert sys.stderr == olderr

    def test_capturing_error_recursive(self):
        with self.getcapture() as cap1:
            print("cap1")
            with self.getcapture() as cap2:
                print("cap2")
                out2, err2 = cap2.readouterr()
                out1, err1 = cap1.readouterr()
        assert out1 == "cap1\n"
        assert out2 == "cap2\n"

    def test_just_out_capture(self):
        with self.getcapture(out=True, err=False) as cap:
            sys.stdout.write("hello")
            sys.stderr.write("world")
            out, err = cap.readouterr()
        assert out == "hello"
        assert not err

    def test_just_err_capture(self):
        with self.getcapture(out=False, err=True) as cap:
            sys.stdout.write("hello")
            sys.stderr.write("world")
            out, err = cap.readouterr()
        assert err == "world"
        assert not out

    def test_stdin_restored(self):
        old = sys.stdin
        with self.getcapture(in_=True):
            newstdin = sys.stdin
        assert newstdin != sys.stdin
        assert sys.stdin is old

    def test_stdin_nulled_by_default(self):
        print("XXX this test may well hang instead of crashing")
        print("XXX which indicates an error in the underlying capturing")
        print("XXX mechanisms")
        with self.getcapture():
            pytest.raises(OSError, sys.stdin.read)


class TestTeeStdCapture(TestStdCapture):
    captureclass = staticmethod(TeeStdCapture)

    def test_capturing_error_recursive(self):
        r"""For TeeStdCapture since we passthrough stderr/stdout, cap1
        should get all output, while cap2 should only get "cap2\n"."""

        with self.getcapture() as cap1:
            print("cap1")
            with self.getcapture() as cap2:
                print("cap2")
                out2, err2 = cap2.readouterr()
                out1, err1 = cap1.readouterr()
        assert out1 == "cap1\ncap2\n"
        assert out2 == "cap2\n"


class TestStdCaptureFD(TestStdCapture):
    captureclass = staticmethod(StdCaptureFD)

    def test_simple_only_fd(self, testdir):
        testdir.makepyfile(
            """\
            import os
            def test_x():
                os.write(1, b"hello\\n")
                assert 0
            """
        )
        result = testdir.runpytest_subprocess()
        result.stdout.fnmatch_lines(
            """
            *test_x*
            *assert 0*
            *Captured stdout*
        """
        )

    def test_intermingling(self):
        with self.getcapture() as cap:
            os.write(1, b"1")
            sys.stdout.write(str(2))
            sys.stdout.flush()
            os.write(1, b"3")
            os.write(2, b"a")
            sys.stderr.write("b")
            sys.stderr.flush()
            os.write(2, b"c")
            out, err = cap.readouterr()
        assert out == "123"
        assert err == "abc"

    def test_many(self, capfd):
        with lsof_check():
            for i in range(10):
                cap = StdCaptureFD()
                cap.start_capturing()
                cap.stop_capturing()


class TestStdCaptureFDinvalidFD:
    def test_stdcapture_fd_invalid_fd(self, testdir):
        testdir.makepyfile(
            """
            import os
            from fnmatch import fnmatch
            from _pytest import capture

            def StdCaptureFD(out=True, err=True, in_=True):
                return capture.MultiCapture(
                    in_=capture.FDCapture(0) if in_ else None,
                    out=capture.FDCapture(1) if out else None,
                    err=capture.FDCapture(2) if err else None,
                )

            def test_stdout():
                os.close(1)
                cap = StdCaptureFD(out=True, err=False, in_=False)
                assert fnmatch(repr(cap.out), "<FDCapture 1 oldfd=* _state='initialized' tmpfile=*>")
                cap.start_capturing()
                os.write(1, b"stdout")
                assert cap.readouterr() == ("stdout", "")
                cap.stop_capturing()

            def test_stderr():
                os.close(2)
                cap = StdCaptureFD(out=False, err=True, in_=False)
                assert fnmatch(repr(cap.err), "<FDCapture 2 oldfd=* _state='initialized' tmpfile=*>")
                cap.start_capturing()
                os.write(2, b"stderr")
                assert cap.readouterr() == ("", "stderr")
                cap.stop_capturing()

            def test_stdin():
                os.close(0)
                cap = StdCaptureFD(out=False, err=False, in_=True)
                assert fnmatch(repr(cap.in_), "<FDCapture 0 oldfd=* _state='initialized' tmpfile=*>")
                cap.stop_capturing()
        """
        )
        result = testdir.runpytest_subprocess("--capture=fd")
        assert result.ret == 0
        assert result.parseoutcomes()["passed"] == 3

    def test_fdcapture_invalid_fd_with_fd_reuse(self, testdir):
        with saved_fd(1):
            os.close(1)
            cap = capture.FDCaptureBinary(1)
            cap.start()
            os.write(1, b"started")
            cap.suspend()
            os.write(1, b" suspended")
            cap.resume()
            os.write(1, b" resumed")
            assert cap.snap() == b"started resumed"
            cap.done()
            with pytest.raises(OSError):
                os.write(1, b"done")

    def test_fdcapture_invalid_fd_without_fd_reuse(self, testdir):
        with saved_fd(1), saved_fd(2):
            os.close(1)
            os.close(2)
            cap = capture.FDCaptureBinary(2)
            cap.start()
            os.write(2, b"started")
            cap.suspend()
            os.write(2, b" suspended")
            cap.resume()
            os.write(2, b" resumed")
            assert cap.snap() == b"started resumed"
            cap.done()
            with pytest.raises(OSError):
                os.write(2, b"done")


def test_capture_not_started_but_reset():
    capsys = StdCapture()
    capsys.stop_capturing()


def test_using_capsys_fixture_works_with_sys_stdout_encoding(capsys):
    test_text = "test text"

    print(test_text.encode(sys.stdout.encoding, "replace"))
    (out, err) = capsys.readouterr()
    assert out
    assert err == ""


def test_capsys_results_accessible_by_attribute(capsys):
    sys.stdout.write("spam")
    sys.stderr.write("eggs")
    capture_result = capsys.readouterr()
    assert capture_result.out == "spam"
    assert capture_result.err == "eggs"


def test_fdcapture_tmpfile_remains_the_same() -> None:
    cap = StdCaptureFD(out=False, err=True)
    try:
        cap.start_capturing()
        capfile = cap.err.tmpfile
        cap.readouterr()
    finally:
        cap.stop_capturing()
    capfile2 = cap.err.tmpfile
    assert capfile2 == capfile


def test_close_and_capture_again(testdir):
    testdir.makepyfile(
        """
        import os
        def test_close():
            os.close(1)
        def test_capture_again():
            os.write(1, b"hello\\n")
            assert 0
    """
    )
    result = testdir.runpytest_subprocess()
    result.stdout.fnmatch_lines(
        """
        *test_capture_again*
        *assert 0*
        *stdout*
        *hello*
    """
    )


@pytest.mark.parametrize(
    "method", ["SysCapture(2)", "SysCapture(2, tee=True)", "FDCapture(2)"]
)
def test_capturing_and_logging_fundamentals(testdir, method: str) -> None:
    # here we check a fundamental feature
    p = testdir.makepyfile(
        """
        import sys, os
        import py, logging
        from _pytest import capture
        cap = capture.MultiCapture(
            in_=None,
            out=None,
            err=capture.%s,
        )
        cap.start_capturing()

        logging.warning("hello1")
        outerr = cap.readouterr()
        print("suspend, captured %%s" %%(outerr,))
        logging.warning("hello2")

        cap.pop_outerr_to_orig()
        logging.warning("hello3")

        outerr = cap.readouterr()
        print("suspend2, captured %%s" %% (outerr,))
    """
        % (method,)
    )
    result = testdir.runpython(p)
    result.stdout.fnmatch_lines(
        """
        suspend, captured*hello1*
        suspend2, captured*WARNING:root:hello3*
    """
    )
    result.stderr.fnmatch_lines(
        """
        WARNING:root:hello2
    """
    )
    assert "atexit" not in result.stderr.str()


def test_error_attribute_issue555(testdir):
    testdir.makepyfile(
        """
        import sys
        def test_capattr():
            assert sys.stdout.errors == "replace"
            assert sys.stderr.errors == "replace"
    """
    )
    reprec = testdir.inline_run()
    reprec.assertoutcome(passed=1)


@pytest.mark.skipif(
    not sys.platform.startswith("win") and sys.version_info[:2] >= (3, 6),
    reason="only py3.6+ on windows",
)
def test_py36_windowsconsoleio_workaround_non_standard_streams() -> None:
    """
    Ensure _py36_windowsconsoleio_workaround function works with objects that
    do not implement the full ``io``-based stream protocol, for example execnet channels (#2666).
    """
    from _pytest.capture import _py36_windowsconsoleio_workaround

    class DummyStream:
        def write(self, s):
            pass

    stream = cast(TextIO, DummyStream())
    _py36_windowsconsoleio_workaround(stream)


def test_dontreadfrominput_has_encoding(testdir):
    testdir.makepyfile(
        """
        import sys
        def test_capattr():
            # should not raise AttributeError
            assert sys.stdout.encoding
            assert sys.stderr.encoding
    """
    )
    reprec = testdir.inline_run()
    reprec.assertoutcome(passed=1)


def test_crash_on_closing_tmpfile_py27(testdir):
    p = testdir.makepyfile(
        """
        import threading
        import sys

        printing = threading.Event()

        def spam():
            f = sys.stderr
            print('SPAMBEFORE', end='', file=f)
            printing.set()

            while True:
                try:
                    f.flush()
                except (OSError, ValueError):
                    break

        def test_spam_in_thread():
            t = threading.Thread(target=spam)
            t.daemon = True
            t.start()

            printing.wait()
    """
    )
    # Do not consider plugins like hypothesis, which might output to stderr.
    testdir.monkeypatch.setenv("PYTEST_DISABLE_PLUGIN_AUTOLOAD", "1")
    result = testdir.runpytest_subprocess(str(p))
    assert result.ret == 0
    assert result.stderr.str() == ""
    result.stdout.no_fnmatch_line("*OSError*")


def test_global_capture_with_live_logging(testdir):
    # Issue 3819
    # capture should work with live cli logging

    # Teardown report seems to have the capture for the whole process (setup, capture, teardown)
    testdir.makeconftest(
        """
        def pytest_runtest_logreport(report):
            if "test_global" in report.nodeid:
                if report.when == "teardown":
                    with open("caplog", "w") as f:
                        f.write(report.caplog)
                    with open("capstdout", "w") as f:
                        f.write(report.capstdout)
        """
    )

    testdir.makepyfile(
        """
        import logging
        import sys
        import pytest

        logger = logging.getLogger(__name__)

        @pytest.fixture
        def fix1():
            print("fix setup")
            logging.info("fix setup")
            yield
            logging.info("fix teardown")
            print("fix teardown")

        def test_global(fix1):
            print("begin test")
            logging.info("something in test")
            print("end test")
        """
    )
    result = testdir.runpytest_subprocess("--log-cli-level=INFO")
    assert result.ret == 0

    with open("caplog") as f:
        caplog = f.read()

    assert "fix setup" in caplog
    assert "something in test" in caplog
    assert "fix teardown" in caplog

    with open("capstdout") as f:
        capstdout = f.read()

    assert "fix setup" in capstdout
    assert "begin test" in capstdout
    assert "end test" in capstdout
    assert "fix teardown" in capstdout


@pytest.mark.parametrize("capture_fixture", ["capsys", "capfd"])
def test_capture_with_live_logging(testdir, capture_fixture):
    # Issue 3819
    # capture should work with live cli logging

    testdir.makepyfile(
        """
        import logging
        import sys

        logger = logging.getLogger(__name__)

        def test_capture({0}):
            print("hello")
            sys.stderr.write("world\\n")
            captured = {0}.readouterr()
            assert captured.out == "hello\\n"
            assert captured.err == "world\\n"

            logging.info("something")
            print("next")
            logging.info("something")

            captured = {0}.readouterr()
            assert captured.out == "next\\n"
        """.format(
            capture_fixture
        )
    )

    result = testdir.runpytest_subprocess("--log-cli-level=INFO")
    assert result.ret == 0


def test_typeerror_encodedfile_write(testdir):
    """It should behave the same with and without output capturing (#4861)."""
    p = testdir.makepyfile(
        """
        def test_fails():
            import sys
            sys.stdout.write(b"foo")
    """
    )
    result_without_capture = testdir.runpytest("-s", str(p))
    result_with_capture = testdir.runpytest(str(p))

    assert result_with_capture.ret == result_without_capture.ret
    out = result_with_capture.stdout.str()
    assert ("TypeError: write() argument must be str, not bytes" in out) or (
        "TypeError: unicode argument expected, got 'bytes'" in out
    )


def test_stderr_write_returns_len(capsys):
    """Write on Encoded files, namely captured stderr, should return number of characters written."""
    assert sys.stderr.write("Foo") == 3


def test_encodedfile_writelines(tmpfile: BinaryIO) -> None:
    ef = capture.EncodedFile(tmpfile, encoding="utf-8")
    with pytest.raises(TypeError):
        ef.writelines([b"line1", b"line2"])
    assert ef.writelines(["line3", "line4"]) is None  # type: ignore[func-returns-value]
    ef.flush()
    tmpfile.seek(0)
    assert tmpfile.read() == b"line3line4"
    tmpfile.close()
    with pytest.raises(ValueError):
        ef.read()


def test__get_multicapture() -> None:
    assert isinstance(_get_multicapture("no"), MultiCapture)
    pytest.raises(ValueError, _get_multicapture, "unknown").match(
        r"^unknown capturing method: 'unknown'"
    )


def test_logging_while_collecting(testdir):
    """Issue #6240: Calls to logging.xxx() during collection causes all logging calls to be duplicated to stderr"""
    p = testdir.makepyfile(
        """\
        import logging

        logging.warning("during collection")

        def test_logging():
            logging.warning("during call")
            assert False
        """
    )
    result = testdir.runpytest_subprocess(p)
    assert result.ret == ExitCode.TESTS_FAILED
    result.stdout.fnmatch_lines(
        [
            "*test_*.py F*",
            "====* FAILURES *====",
            "____*____",
            "*--- Captured log call*",
            "WARNING * during call",
            "*1 failed*",
        ]
    )
    result.stdout.no_fnmatch_line("*Captured stderr call*")
    result.stdout.no_fnmatch_line("*during collection*")