test_warnings.py

import warnings

import pytest

WARNINGS_SUMMARY_HEADER = "warnings summary"


@pytest.fixture
def pyfile_with_warnings(testdir, request):
    """
    Create a test file which calls a function in a module which generates warnings.
    """
    testdir.syspathinsert()
    test_name = request.function.__name__
    module_name = test_name.lstrip("test_") + "_module"
    testdir.makepyfile(
        **{
            module_name: """
            import warnings
            def foo():
                warnings.warn(UserWarning("user warning"))
                warnings.warn(RuntimeWarning("runtime warning"))
                return 1
        """,
            test_name: """
            import {module_name}
            def test_func():
                assert {module_name}.foo() == 1
        """.format(
                module_name=module_name
            ),
        }
    )


@pytest.mark.filterwarnings("default")
def test_normal_flow(testdir, pyfile_with_warnings):
    """
    Check that the warnings section is displayed.
    """
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(
        [
            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
            "test_normal_flow.py::test_func",
            "*normal_flow_module.py:3: UserWarning: user warning",
            '*  warnings.warn(UserWarning("user warning"))',
            "*normal_flow_module.py:4: RuntimeWarning: runtime warning",
            '*  warnings.warn(RuntimeWarning("runtime warning"))',
            "* 1 passed, 2 warnings*",
        ]
    )


@pytest.mark.filterwarnings("always")
def test_setup_teardown_warnings(testdir, pyfile_with_warnings):
    testdir.makepyfile(
        """
        import warnings
        import pytest

        @pytest.fixture
        def fix():
            warnings.warn(UserWarning("warning during setup"))
            yield
            warnings.warn(UserWarning("warning during teardown"))

        def test_func(fix):
            pass
    """
    )
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(
        [
            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
            "*test_setup_teardown_warnings.py:6: UserWarning: warning during setup",
            '*warnings.warn(UserWarning("warning during setup"))',
            "*test_setup_teardown_warnings.py:8: UserWarning: warning during teardown",
            '*warnings.warn(UserWarning("warning during teardown"))',
            "* 1 passed, 2 warnings*",
        ]
    )


@pytest.mark.parametrize("method", ["cmdline", "ini"])
def test_as_errors(testdir, pyfile_with_warnings, method):
    args = ("-W", "error") if method == "cmdline" else ()
    if method == "ini":
        testdir.makeini(
            """
            [pytest]
            filterwarnings=error
            """
        )
    # Use a subprocess, since changing logging level affects other threads
    # (xdist).
    result = testdir.runpytest_subprocess(*args)
    result.stdout.fnmatch_lines(
        [
            "E       UserWarning: user warning",
            "as_errors_module.py:3: UserWarning",
            "* 1 failed in *",
        ]
    )


@pytest.mark.parametrize("method", ["cmdline", "ini"])
def test_ignore(testdir, pyfile_with_warnings, method):
    args = ("-W", "ignore") if method == "cmdline" else ()
    if method == "ini":
        testdir.makeini(
            """
        [pytest]
        filterwarnings= ignore
        """
        )

    result = testdir.runpytest(*args)
    result.stdout.fnmatch_lines(["* 1 passed in *"])
    assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()


@pytest.mark.filterwarnings("always")
def test_unicode(testdir, pyfile_with_warnings):
    testdir.makepyfile(
        """\
        import warnings
        import pytest


        @pytest.fixture
        def fix():
            warnings.warn("测试")
            yield

        def test_func(fix):
            pass
        """
    )
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(
        [
            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
            "*test_unicode.py:7: UserWarning: \u6d4b\u8bd5*",
            "* 1 passed, 1 warning*",
        ]
    )


def test_works_with_filterwarnings(testdir):
    """Ensure our warnings capture does not mess with pre-installed filters (#2430)."""
    testdir.makepyfile(
        """
        import warnings

        class MyWarning(Warning):
            pass

        warnings.filterwarnings("error", category=MyWarning)

        class TestWarnings(object):
            def test_my_warning(self):
                try:
                    warnings.warn(MyWarning("warn!"))
                    assert False
                except MyWarning:
                    assert True
    """
    )
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(["*== 1 passed in *"])


@pytest.mark.parametrize("default_config", ["ini", "cmdline"])
def test_filterwarnings_mark(testdir, default_config):
    """
    Test ``filterwarnings`` mark works and takes precedence over command line and ini options.
    """
    if default_config == "ini":
        testdir.makeini(
            """
            [pytest]
            filterwarnings = always
        """
        )
    testdir.makepyfile(
        """
        import warnings
        import pytest

        @pytest.mark.filterwarnings('ignore::RuntimeWarning')
        def test_ignore_runtime_warning():
            warnings.warn(RuntimeWarning())

        @pytest.mark.filterwarnings('error')
        def test_warning_error():
            warnings.warn(RuntimeWarning())

        def test_show_warning():
            warnings.warn(RuntimeWarning())
    """
    )
    result = testdir.runpytest("-W always" if default_config == "cmdline" else "")
    result.stdout.fnmatch_lines(["*= 1 failed, 2 passed, 1 warning in *"])


def test_non_string_warning_argument(testdir):
    """Non-str argument passed to warning breaks pytest (#2956)"""
    testdir.makepyfile(
        """\
        import warnings
        import pytest

        def test():
            warnings.warn(UserWarning(1, 'foo'))
        """
    )
    result = testdir.runpytest("-W", "always")
    result.stdout.fnmatch_lines(["*= 1 passed, 1 warning in *"])


def test_filterwarnings_mark_registration(testdir):
    """Ensure filterwarnings mark is registered"""
    testdir.makepyfile(
        """
        import pytest

        @pytest.mark.filterwarnings('error')
        def test_func():
            pass
    """
    )
    result = testdir.runpytest("--strict-markers")
    assert result.ret == 0


@pytest.mark.filterwarnings("always")
def test_warning_captured_hook(testdir):
    testdir.makeconftest(
        """
        from _pytest.warnings import _issue_warning_captured
        def pytest_configure(config):
            _issue_warning_captured(UserWarning("config warning"), config.hook, stacklevel=2)
    """
    )
    testdir.makepyfile(
        """
        import pytest, warnings

        warnings.warn(UserWarning("collect warning"))

        @pytest.fixture
        def fix():
            warnings.warn(UserWarning("setup warning"))
            yield 1
            warnings.warn(UserWarning("teardown warning"))

        def test_func(fix):
            warnings.warn(UserWarning("call warning"))
            assert fix == 1
        """
    )

    collected = []

    class WarningCollector:
        def pytest_warning_captured(self, warning_message, when, item):
            imge_name = item.name if item is not None else ""
            collected.append((str(warning_message.message), when, imge_name))

    result = testdir.runpytest(plugins=[WarningCollector()])
    result.stdout.fnmatch_lines(["*1 passed*"])

    expected = [
        ("config warning", "config", ""),
        ("collect warning", "collect", ""),
        ("setup warning", "runtest", "test_func"),
        ("call warning", "runtest", "test_func"),
        ("teardown warning", "runtest", "test_func"),
    ]
    assert collected == expected


@pytest.mark.filterwarnings("always")
def test_collection_warnings(testdir):
    """
    Check that we also capture warnings issued during test collection (#3251).
    """
    testdir.makepyfile(
        """
        import warnings

        warnings.warn(UserWarning("collection warning"))

        def test_foo():
            pass
    """
    )
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(
        [
            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
            "  *collection_warnings.py:3: UserWarning: collection warning",
            '    warnings.warn(UserWarning("collection warning"))',
            "* 1 passed, 1 warning*",
        ]
    )


@pytest.mark.filterwarnings("always")
def test_mark_regex_escape(testdir):
    """@pytest.mark.filterwarnings should not try to escape regex characters (#3936)"""
    testdir.makepyfile(
        r"""
        import pytest, warnings

        @pytest.mark.filterwarnings(r"ignore:some \(warning\)")
        def test_foo():
            warnings.warn(UserWarning("some (warning)"))
    """
    )
    result = testdir.runpytest()
    assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()


@pytest.mark.filterwarnings("default")
@pytest.mark.parametrize("ignore_pytest_warnings", ["no", "ini", "cmdline"])
def test_hide_pytest_internal_warnings(testdir, ignore_pytest_warnings):
    """Make sure we can ignore internal pytest warnings using a warnings filter."""
    testdir.makepyfile(
        """
        import pytest
        import warnings

        warnings.warn(pytest.PytestWarning("some internal warning"))

        def test_bar():
            pass
    """
    )
    if ignore_pytest_warnings == "ini":
        testdir.makeini(
            """
            [pytest]
            filterwarnings = ignore::pytest.PytestWarning
        """
        )
    args = (
        ["-W", "ignore::pytest.PytestWarning"]
        if ignore_pytest_warnings == "cmdline"
        else []
    )
    result = testdir.runpytest(*args)
    if ignore_pytest_warnings != "no":
        assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()
    else:
        result.stdout.fnmatch_lines(
            [
                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
                "*test_hide_pytest_internal_warnings.py:4: PytestWarning: some internal warning",
                "* 1 passed, 1 warning *",
            ]
        )


@pytest.mark.parametrize("ignore_on_cmdline", [True, False])
def test_option_precedence_cmdline_over_ini(testdir, ignore_on_cmdline):
    """filters defined in the command-line should take precedence over filters in ini files (#3946)."""
    testdir.makeini(
        """
        [pytest]
        filterwarnings = error
    """
    )
    testdir.makepyfile(
        """
        import warnings
        def test():
            warnings.warn(UserWarning('hello'))
    """
    )
    args = ["-W", "ignore"] if ignore_on_cmdline else []
    result = testdir.runpytest(*args)
    if ignore_on_cmdline:
        result.stdout.fnmatch_lines(["* 1 passed in*"])
    else:
        result.stdout.fnmatch_lines(["* 1 failed in*"])


def test_option_precedence_mark(testdir):
    """Filters defined by marks should always take precedence (#3946)."""
    testdir.makeini(
        """
        [pytest]
        filterwarnings = ignore
    """
    )
    testdir.makepyfile(
        """
        import pytest, warnings
        @pytest.mark.filterwarnings('error')
        def test():
            warnings.warn(UserWarning('hello'))
    """
    )
    result = testdir.runpytest("-W", "ignore")
    result.stdout.fnmatch_lines(["* 1 failed in*"])


class TestDeprecationWarningsByDefault:
    """
    Note: all pytest runs are executed in a subprocess so we don't inherit warning filters
    from pytest's own test suite
    """

    def create_file(self, testdir, mark=""):
        testdir.makepyfile(
            """
            import pytest, warnings

            warnings.warn(DeprecationWarning("collection"))

            {mark}
            def test_foo():
                warnings.warn(PendingDeprecationWarning("test run"))
        """.format(
                mark=mark
            )
        )

    @pytest.mark.parametrize("customize_filters", [True, False])
    def test_shown_by_default(self, testdir, customize_filters):
        """Show deprecation warnings by default, even if user has customized the warnings filters (#4013)."""
        self.create_file(testdir)
        if customize_filters:
            testdir.makeini(
                """
                [pytest]
                filterwarnings =
                    once::UserWarning
            """
            )
        result = testdir.runpytest_subprocess()
        result.stdout.fnmatch_lines(
            [
                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
                "*test_shown_by_default.py:3: DeprecationWarning: collection",
                "*test_shown_by_default.py:7: PendingDeprecationWarning: test run",
                "* 1 passed, 2 warnings*",
            ]
        )

    def test_hidden_by_ini(self, testdir):
        self.create_file(testdir)
        testdir.makeini(
            """
            [pytest]
            filterwarnings =
                ignore::DeprecationWarning
                ignore::PendingDeprecationWarning
        """
        )
        result = testdir.runpytest_subprocess()
        assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()

    def test_hidden_by_mark(self, testdir):
        """Should hide the deprecation warning from the function, but the warning during collection should
        be displayed normally.
        """
        self.create_file(
            testdir,
            mark='@pytest.mark.filterwarnings("ignore::PendingDeprecationWarning")',
        )
        result = testdir.runpytest_subprocess()
        result.stdout.fnmatch_lines(
            [
                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
                "*test_hidden_by_mark.py:3: DeprecationWarning: collection",
                "* 1 passed, 1 warning*",
            ]
        )

    def test_hidden_by_cmdline(self, testdir):
        self.create_file(testdir)
        result = testdir.runpytest_subprocess(
            "-W",
            "ignore::DeprecationWarning",
            "-W",
            "ignore::PendingDeprecationWarning",
        )
        assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()

    def test_hidden_by_system(self, testdir, monkeypatch):
        self.create_file(testdir)
        monkeypatch.setenv("PYTHONWARNINGS", "once::UserWarning")
        result = testdir.runpytest_subprocess()
        assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()


@pytest.mark.parametrize("change_default", [None, "ini", "cmdline"])
@pytest.mark.skip(
    reason="This test should be enabled again before pytest 6.0 is released"
)
def test_deprecation_warning_as_error(testdir, change_default):
    """This ensures that PytestDeprecationWarnings raised by pytest are turned into errors.

    This test should be enabled as part of each major release, and skipped again afterwards
    to ensure our deprecations are turning into warnings as expected.
    """
    testdir.makepyfile(
        """
        import warnings, pytest
        def test():
            warnings.warn(pytest.PytestDeprecationWarning("some warning"))
    """
    )
    if change_default == "ini":
        testdir.makeini(
            """
            [pytest]
            filterwarnings =
                ignore::pytest.PytestDeprecationWarning
        """
        )

    args = (
        ("-Wignore::pytest.PytestDeprecationWarning",)
        if change_default == "cmdline"
        else ()
    )
    result = testdir.runpytest(*args)
    if change_default is None:
        result.stdout.fnmatch_lines(["* 1 failed in *"])
    else:
        assert change_default in ("ini", "cmdline")
        result.stdout.fnmatch_lines(["* 1 passed in *"])


class TestAssertionWarnings:
    @staticmethod
    def assert_result_warns(result, msg):
        result.stdout.fnmatch_lines(["*PytestAssertRewriteWarning: %s*" % msg])

    def test_tuple_warning(self, testdir):
        testdir.makepyfile(
            """\
            def test_foo():
                assert (1,2)
            """
        )
        result = testdir.runpytest()
        self.assert_result_warns(
            result, "assertion is always true, perhaps remove parentheses?"
        )


def test_warnings_checker_twice():
    """Issue #4617"""
    expectation = pytest.warns(UserWarning)
    with expectation:
        warnings.warn("Message A", UserWarning)
    with expectation:
        warnings.warn("Message B", UserWarning)


@pytest.mark.filterwarnings("ignore::pytest.PytestExperimentalApiWarning")
@pytest.mark.filterwarnings("always")
def test_group_warnings_by_message(testdir):
    testdir.copy_example("warnings/test_group_warnings_by_message.py")
    result = testdir.runpytest()
    result.stdout.fnmatch_lines(
        [
            "test_group_warnings_by_message.py::test_foo[0]",
            "test_group_warnings_by_message.py::test_foo[1]",
            "test_group_warnings_by_message.py::test_foo[2]",
            "test_group_warnings_by_message.py::test_foo[3]",
            "test_group_warnings_by_message.py::test_foo[4]",
            "test_group_warnings_by_message.py::test_bar",
        ]
    )
    warning_code = 'warnings.warn(UserWarning("foo"))'
    assert warning_code in result.stdout.str()
    assert result.stdout.str().count(warning_code) == 1


def test_pytest_configure_warning(testdir, recwarn):
    """Issue 5115."""
    testdir.makeconftest(
        """
        def pytest_configure():
            import warnings

            warnings.warn("from pytest_configure")
        """
    )

    result = testdir.runpytest()
    assert result.ret == 5
    assert "INTERNALERROR" not in result.stderr.str()
    warning = recwarn.pop()
    assert str(warning.message) == "from pytest_configure"