from __future__ import annotations

import sys
from pathlib import Path
from typing import Literal

import pytest

IS_PY311 = sys.version_info[:2] >= (3, 11)


@pytest.mark.parametrize("mode", ["normal", "xdist"])
class TestFixture:
    """
    Tests for ``subtests`` fixture.
    """

    @pytest.fixture
    def simple_script(self, pytester: pytest.Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo(subtests):
                for i in range(5):
                    with subtests.test(msg="custom", i=i):
                        assert i % 2 == 0
        """
        )

    def test_simple_terminal_normal(
        self,
        simple_script: None,
        pytester: pytest.Pytester,
        mode: Literal["normal", "xdist"],
    ) -> None:
        if mode == "normal":
            result = pytester.runpytest()
            expected_lines = ["collected 1 item"]
        else:
            assert mode == "xdist"
            pytest.importorskip("xdist")
            result = pytester.runpytest("-n1")
            expected_lines = ["1 worker [1 item]"]

        expected_lines += [
            "* test_foo [[]custom[]] (i=1) *",
            "* test_foo [[]custom[]] (i=3) *",
            "* 2 failed, 1 passed, 3 subtests passed in *",
        ]
        result.stdout.fnmatch_lines(expected_lines)

    def test_simple_terminal_verbose(
        self,
        simple_script: None,
        pytester: pytest.Pytester,
        mode: Literal["normal", "xdist"],
    ) -> None:
        if mode == "normal":
            result = pytester.runpytest("-v")
            expected_lines = [
                "*collected 1 item",
                "test_simple_terminal_verbose.py::test_foo [[]custom[]] (i=0) SUBPASS *100%*",
                "test_simple_terminal_verbose.py::test_foo [[]custom[]] (i=1) SUBFAIL *100%*",
                "test_simple_terminal_verbose.py::test_foo [[]custom[]] (i=2) SUBPASS *100%*",
                "test_simple_terminal_verbose.py::test_foo [[]custom[]] (i=3) SUBFAIL *100%*",
                "test_simple_terminal_verbose.py::test_foo [[]custom[]] (i=4) SUBPASS *100%*",
                "test_simple_terminal_verbose.py::test_foo PASSED *100%*",
            ]
        else:
            assert mode == "xdist"
            pytest.importorskip("xdist")
            result = pytester.runpytest("-n1", "-v")
            expected_lines = [
                "1 worker [1 item]",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
                "*gw0*100%* test_simple_terminal_verbose.py::test_foo*",
            ]

        expected_lines += [
            "* test_foo [[]custom[]] (i=1) *",
            "* test_foo [[]custom[]] (i=3) *",
            "* 2 failed, 1 passed, 3 subtests passed in *",
        ]
        result.stdout.fnmatch_lines(expected_lines)

    def test_skip(
        self, pytester: pytest.Pytester, mode: Literal["normal", "xdist"]
    ) -> None:
        pytester.makepyfile(
            """
            import pytest
            def test_foo(subtests):
                for i in range(5):
                    with subtests.test(msg="custom", i=i):
                        if i % 2 == 0:
                            pytest.skip('even number')
        """
        )
        if mode == "normal":
            result = pytester.runpytest()
            expected_lines = ["collected 1 item"]
        else:
            assert mode == "xdist"
            pytest.importorskip("xdist")
            result = pytester.runpytest("-n1")
            expected_lines = ["1 worker [1 item]"]
        expected_lines += ["* 1 passed, 3 skipped, 2 subtests passed in *"]
        result.stdout.fnmatch_lines(expected_lines)

    def test_xfail(
        self, pytester: pytest.Pytester, mode: Literal["normal", "xdist"]
    ) -> None:
        pytester.makepyfile(
            """
            import pytest
            def test_foo(subtests):
                for i in range(5):
                    with subtests.test(msg="custom", i=i):
                        if i % 2 == 0:
                            pytest.xfail('even number')
        """
        )
        if mode == "normal":
            result = pytester.runpytest()
            expected_lines = ["collected 1 item"]
        else:
            assert mode == "xdist"
            pytest.importorskip("xdist")
            result = pytester.runpytest("-n1")
            expected_lines = ["1 worker [1 item]"]
        expected_lines += ["* 1 passed, 2 subtests passed, 3 subtests xfailed in *"]
        result.stdout.fnmatch_lines(expected_lines)

    def test_typing_exported(
        self, pytester: pytest.Pytester, mode: Literal["normal", "xdist"]
    ) -> None:
        pytester.makepyfile(
            """
            from pytest_subtests import SubTests

            def test_typing_exported(subtests: SubTests) -> None:
                assert isinstance(subtests, SubTests)
            """
        )
        if mode == "normal":
            result = pytester.runpytest()
            expected_lines = ["collected 1 item"]
        else:
            assert mode == "xdist"
            pytest.importorskip("xdist")
            result = pytester.runpytest("-n1")
            expected_lines = ["1 worker [1 item]"]
        expected_lines += ["* 1 passed *"]
        result.stdout.fnmatch_lines(expected_lines)


class TestSubTest:
    """
    Test Test.subTest functionality.
    """

    @pytest.fixture
    def simple_script(self, pytester: pytest.Pytester) -> Path:
        return pytester.makepyfile(
            """
            from unittest import TestCase, main

            class T(TestCase):

                def test_foo(self):
                    for i in range(5):
                        with self.subTest(msg="custom", i=i):
                            self.assertEqual(i % 2, 0)

            if __name__ == '__main__':
                main()
        """
        )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    def test_simple_terminal_normal(
        self,
        simple_script: Path,
        pytester: pytest.Pytester,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        suffix = ".test_foo" if IS_PY311 else ""
        if runner == "unittest":
            result = pytester.run(sys.executable, simple_script)
            result.stderr.fnmatch_lines(
                [
                    f"FAIL: test_foo (__main__.T{suffix}) [custom] (i=1)",
                    "AssertionError: 1 != 0",
                    f"FAIL: test_foo (__main__.T{suffix}) [custom] (i=3)",
                    "AssertionError: 1 != 0",
                    "Ran 1 test in *",
                    "FAILED (failures=2)",
                ]
            )
        else:
            if runner == "pytest-normal":
                result = pytester.runpytest(simple_script)
                expected_lines = ["collected 1 item"]
            else:
                assert runner == "pytest-xdist"
                pytest.importorskip("xdist")
                result = pytester.runpytest(simple_script, "-n1")
                expected_lines = ["1 worker [1 item]"]
            result.stdout.fnmatch_lines(
                expected_lines
                + [
                    "* T.test_foo [[]custom[]] (i=1) *",
                    "E  * AssertionError: 1 != 0",
                    "* T.test_foo [[]custom[]] (i=3) *",
                    "E  * AssertionError: 1 != 0",
                    "* 2 failed, 1 passed, 3 subtests passed in *",
                ]
            )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    def test_simple_terminal_verbose(
        self,
        simple_script: Path,
        pytester: pytest.Pytester,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        suffix = ".test_foo" if IS_PY311 else ""
        if runner == "unittest":
            result = pytester.run(sys.executable, simple_script, "-v")
            result.stderr.fnmatch_lines(
                [
                    f"test_foo (__main__.T{suffix}) ... ",
                    f"FAIL: test_foo (__main__.T{suffix}) [custom] (i=1)",
                    "AssertionError: 1 != 0",
                    f"FAIL: test_foo (__main__.T{suffix}) [custom] (i=3)",
                    "AssertionError: 1 != 0",
                    "Ran 1 test in *",
                    "FAILED (failures=2)",
                ]
            )
        else:
            if runner == "pytest-normal":
                result = pytester.runpytest(simple_script, "-v")
                expected_lines = [
                    "*collected 1 item",
                    "test_simple_terminal_verbose.py::T::test_foo [[]custom[]] (i=1) SUBFAIL *100%*",
                    "test_simple_terminal_verbose.py::T::test_foo [[]custom[]] (i=3) SUBFAIL *100%*",
                    "test_simple_terminal_verbose.py::T::test_foo PASSED *100%*",
                ]
            else:
                assert runner == "pytest-xdist"
                pytest.importorskip("xdist")
                result = pytester.runpytest(simple_script, "-n1", "-v")
                expected_lines = [
                    "1 worker [1 item]",
                    "*gw0*100%* SUBFAIL test_simple_terminal_verbose.py::T::test_foo*",
                    "*gw0*100%* SUBFAIL test_simple_terminal_verbose.py::T::test_foo*",
                    "*gw0*100%* PASSED test_simple_terminal_verbose.py::T::test_foo*",
                ]
            result.stdout.fnmatch_lines(
                expected_lines
                + [
                    "* T.test_foo [[]custom[]] (i=1) *",
                    "E  * AssertionError: 1 != 0",
                    "* T.test_foo [[]custom[]] (i=3) *",
                    "E  * AssertionError: 1 != 0",
                    "* 2 failed, 1 passed, 3 subtests passed in *",
                ]
            )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    def test_skip(
        self,
        pytester: pytest.Pytester,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        p = pytester.makepyfile(
            """
            from unittest import TestCase, main

            class T(TestCase):

                def test_foo(self):
                    for i in range(5):
                        with self.subTest(msg="custom", i=i):
                            if i % 2 == 0:
                                self.skipTest('even number')

            if __name__ == '__main__':
                main()
        """
        )
        if runner == "unittest":
            result = pytester.runpython(p)
            result.stderr.fnmatch_lines(["Ran 1 test in *", "OK (skipped=3)"])
        else:
            pytest.xfail("Not producing the expected results (#5)")
            result = pytester.runpytest(p)  # type:ignore[unreachable]
            result.stdout.fnmatch_lines(
                ["collected 1 item", "* 3 skipped, 1 passed in *"]
            )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    @pytest.mark.xfail(reason="Not producing the expected results (#5)")
    def test_xfail(
        self,
        pytester: pytest.Pytester,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        p = pytester.makepyfile(
            """
            import pytest
            from unittest import expectedFailure, TestCase, main

            class T(TestCase):
                @expectedFailure
                def test_foo(self):
                    for i in range(5):
                        with self.subTest(msg="custom", i=i):
                            if i % 2 == 0:
                                raise pytest.xfail('even number')

            if __name__ == '__main__':
                main()
        """
        )
        if runner == "unittest":
            result = pytester.runpython(p)
            result.stderr.fnmatch_lines(["Ran 1 test in *", "OK (expected failures=3)"])
        else:
            result = pytester.runpytest(p)
            result.stdout.fnmatch_lines(
                ["collected 1 item", "* 3 xfailed, 1 passed in *"]
            )

    @pytest.mark.parametrize("runner", ["pytest-normal"])
    def test_only_original_skip_is_called(
        self,
        pytester: pytest.Pytester,
        monkeypatch: pytest.MonkeyPatch,
        runner: Literal["pytest-normal"],
    ) -> None:
        """Regression test for #173."""
        monkeypatch.setenv("COLUMNS", "200")
        p = pytester.makepyfile(
            """
            import unittest
            from unittest import TestCase, main

            @unittest.skip("skip this test")
            class T(unittest.TestCase):
                def test_foo(self):
                    assert 1 == 2

            if __name__ == '__main__':
                main()
        """
        )
        result = pytester.runpytest(p, "-v", "-rsf")
        result.stdout.fnmatch_lines(
            ["SKIPPED [1] test_only_original_skip_is_called.py:6: skip this test"]
        )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    def test_skip_with_failure(
        self,
        pytester: pytest.Pytester,
        monkeypatch: pytest.MonkeyPatch,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        monkeypatch.setenv("COLUMNS", "200")
        p = pytester.makepyfile(
            """
            import pytest
            from unittest import expectedFailure, TestCase, main

            class T(TestCase):
                def test_foo(self):
                    for i in range(10):
                        with self.subTest("custom message", i=i):
                            if i < 4:
                                self.skipTest(f"skip subtest i={i}")
                            assert i < 4

            if __name__ == '__main__':
                main()
        """
        )
        if runner == "unittest":
            result = pytester.runpython(p)
            if sys.version_info < (3, 11):
                result.stderr.re_match_lines(
                    [
                        r"FAIL: test_foo \(__main__\.T\) \[custom message\] \(i=4\).*",
                        r"FAIL: test_foo \(__main__\.T\) \[custom message\] \(i=9\).*",
                        r"Ran 1 test in .*",
                        r"FAILED \(failures=6, skipped=4\)",
                    ]
                )
            else:
                result.stderr.re_match_lines(
                    [
                        r"FAIL: test_foo \(__main__\.T\.test_foo\) \[custom message\] \(i=4\).*",
                        r"FAIL: test_foo \(__main__\.T\.test_foo\) \[custom message\] \(i=9\).*",
                        r"Ran 1 test in .*",
                        r"FAILED \(failures=6, skipped=4\)",
                    ]
                )
        elif runner == "pytest-normal":
            result = pytester.runpytest(p, "-v", "-rsf")
            result.stdout.re_match_lines(
                [
                    r"test_skip_with_failure.py::T::test_foo \[custom message\] \(i=0\) SUBSKIP \(skip subtest i=0\) .*",
                    r"test_skip_with_failure.py::T::test_foo \[custom message\] \(i=3\) SUBSKIP \(skip subtest i=3\) .*",
                    r"test_skip_with_failure.py::T::test_foo \[custom message\] \(i=4\) SUBFAIL .*",
                    r"test_skip_with_failure.py::T::test_foo \[custom message\] \(i=9\) SUBFAIL .*",
                    "test_skip_with_failure.py::T::test_foo PASSED .*",
                    r"[custom message] (i=0) SUBSKIP [1] test_skip_with_failure.py:5: skip subtest i=0",
                    r"[custom message] (i=0) SUBSKIP [1] test_skip_with_failure.py:5: skip subtest i=3",
                    r"[custom message] (i=4) SUBFAIL test_skip_with_failure.py::T::test_foo - AssertionError: assert 4 < 4",
                    r"[custom message] (i=9) SUBFAIL test_skip_with_failure.py::T::test_foo - AssertionError: assert 9 < 4",
                    r".* 6 failed, 1 passed, 4 skipped in .*",
                ]
            )
        else:
            pytest.xfail("Not producing the expected results (#5)")
            result = pytester.runpytest(p)  # type:ignore[unreachable]
            result.stdout.fnmatch_lines(
                ["collected 1 item", "* 3 skipped, 1 passed in *"]
            )

    @pytest.mark.parametrize("runner", ["unittest", "pytest-normal", "pytest-xdist"])
    def test_skip_with_failure_and_non_subskip(
        self,
        pytester: pytest.Pytester,
        monkeypatch: pytest.MonkeyPatch,
        runner: Literal["unittest", "pytest-normal", "pytest-xdist"],
    ) -> None:
        monkeypatch.setenv("COLUMNS", "200")
        p = pytester.makepyfile(
            """
            import pytest
            from unittest import expectedFailure, TestCase, main

            class T(TestCase):
                def test_foo(self):
                    for i in range(10):
                        with self.subTest("custom message", i=i):
                            if i < 4:
                                self.skipTest(f"skip subtest i={i}")
                            assert i < 4
                    self.skipTest(f"skip the test")

            if __name__ == '__main__':
                main()
        """
        )
        if runner == "unittest":
            result = pytester.runpython(p)
            if sys.version_info < (3, 11):
                result.stderr.re_match_lines(
                    [
                        r"FAIL: test_foo \(__main__\.T\) \[custom message\] \(i=4\).*",
                        r"FAIL: test_foo \(__main__\.T\) \[custom message\] \(i=9\).*",
                        r"Ran 1 test in .*",
                        r"FAILED \(failures=6, skipped=5\)",
                    ]
                )
            else:
                result.stderr.re_match_lines(
                    [
                        r"FAIL: test_foo \(__main__\.T\.test_foo\) \[custom message\] \(i=4\).*",
                        r"FAIL: test_foo \(__main__\.T\.test_foo\) \[custom message\] \(i=9\).*",
                        r"Ran 1 test in .*",
                        r"FAILED \(failures=6, skipped=5\)",
                    ]
                )
        elif runner == "pytest-normal":
            result = pytester.runpytest(p, "-v", "-rsf")
            # The `(i=0)` is not correct but it's given by pytest `TerminalReporter` without `--no-fold-skipped`
            result.stdout.re_match_lines(
                [
                    r"test_skip_with_failure_and_non_subskip.py::T::test_foo \[custom message\] \(i=4\) SUBFAIL .*",
                    r"test_skip_with_failure_and_non_subskip.py::T::test_foo SKIPPED \(skip the test\)",
                    r"\[custom message\] \(i=0\) SUBSKIP \[1\] test_skip_with_failure_and_non_subskip.py:5: skip subtest i=3",
                    r"\[custom message\] \(i=0\) SUBSKIP \[1\] test_skip_with_failure_and_non_subskip.py:5: skip the test",
                    r"\[custom message\] \(i=4\) SUBFAIL test_skip_with_failure_and_non_subskip.py::T::test_foo",
                    r".* 6 failed, 5 skipped in .*",
                ]
            )
            # Check with `--no-fold-skipped` (which gives the correct information).
            if sys.version_info >= (3, 10) and pytest.version_tuple[:2] >= (8, 3):
                result = pytester.runpytest(p, "-v", "--no-fold-skipped", "-rsf")
                result.stdout.re_match_lines(
                    [
                        r"test_skip_with_failure_and_non_subskip.py::T::test_foo \[custom message\] \(i=4\) SUBFAIL .*",
                        r"test_skip_with_failure_and_non_subskip.py::T::test_foo SKIPPED \(skip the test\).*",
                        r"\[custom message\] \(i=3\) SUBSKIP test_skip_with_failure_and_non_subskip.py::T::test_foo - Skipped: skip subtest i=3",
                        r"SKIPPED test_skip_with_failure_and_non_subskip.py::T::test_foo - Skipped: skip the test",
                        r"\[custom message\] \(i=4\) SUBFAIL test_skip_with_failure_and_non_subskip.py::T::test_foo",
                        r".* 6 failed, 5 skipped in .*",
                    ]
                )
        else:
            pytest.xfail("Not producing the expected results (#5)")
            result = pytester.runpytest(p)  # type:ignore[unreachable]
            result.stdout.fnmatch_lines(
                ["collected 1 item", "* 3 skipped, 1 passed in *"]
            )


class TestCapture:
    def create_file(self, pytester: pytest.Pytester) -> None:
        pytester.makepyfile(
            """
                    import sys
                    def test(subtests):
                        print()
                        print('start test')

                        with subtests.test(i='A'):
                            print("hello stdout A")
                            print("hello stderr A", file=sys.stderr)
                            assert 0

                        with subtests.test(i='B'):
                            print("hello stdout B")
                            print("hello stderr B", file=sys.stderr)
                            assert 0

                        print('end test')
                        assert 0
                """
        )

    def test_capturing(self, pytester: pytest.Pytester) -> None:
        self.create_file(pytester)
        result = pytester.runpytest()
        result.stdout.fnmatch_lines(
            [
                "*__ test (i='A') __*",
                "*Captured stdout call*",
                "hello stdout A",
                "*Captured stderr call*",
                "hello stderr A",
                "*__ test (i='B') __*",
                "*Captured stdout call*",
                "hello stdout B",
                "*Captured stderr call*",
                "hello stderr B",
                "*__ test __*",
                "*Captured stdout call*",
                "start test",
                "end test",
            ]
        )

    def test_no_capture(self, pytester: pytest.Pytester) -> None:
        self.create_file(pytester)
        result = pytester.runpytest("-s")
        result.stdout.fnmatch_lines(
            [
                "start test",
                "hello stdout A",
                "uhello stdout B",
                "uend test",
                "*__ test (i='A') __*",
                "*__ test (i='B') __*",
                "*__ test __*",
            ]
        )
        result.stderr.fnmatch_lines(["hello stderr A", "hello stderr B"])

    @pytest.mark.parametrize("fixture", ["capsys", "capfd"])
    def test_capture_with_fixture(
        self, pytester: pytest.Pytester, fixture: Literal["capsys", "capfd"]
    ) -> None:
        pytester.makepyfile(
            rf"""
            import sys

            def test(subtests, {fixture}):
                print('start test')

                with subtests.test(i='A'):
                    print("hello stdout A")
                    print("hello stderr A", file=sys.stderr)

                out, err = {fixture}.readouterr()
                assert out == 'start test\nhello stdout A\n'
                assert err == 'hello stderr A\n'
            """
        )
        result = pytester.runpytest()
        result.stdout.fnmatch_lines(
            [
                "*1 passed*",
            ]
        )


class TestLogging:
    def create_file(self, pytester: pytest.Pytester) -> None:
        pytester.makepyfile(
            """
            import logging

            def test_foo(subtests):
                logging.info("before")

                with subtests.test("sub1"):
                    print("sub1 stdout")
                    logging.info("sub1 logging")

                with subtests.test("sub2"):
                    print("sub2 stdout")
                    logging.info("sub2 logging")
                    assert False
            """
        )

    def test_capturing(self, pytester: pytest.Pytester) -> None:
        self.create_file(pytester)
        result = pytester.runpytest("--log-level=INFO")
        result.stdout.fnmatch_lines(
            [
                "*___ test_foo [[]sub2[]] __*",
                "*-- Captured stdout call --*",
                "sub2 stdout",
                "*-- Captured log call ---*",
                "INFO     root:test_capturing.py:12 sub2 logging",
                "*== short test summary info ==*",
            ]
        )

    def test_caplog(self, pytester: pytest.Pytester) -> None:
        pytester.makepyfile(
            """
            import logging

            def test(subtests, caplog):
                caplog.set_level(logging.INFO)
                logging.info("start test")

                with subtests.test("sub1"):
                    logging.info("inside %s", "subtest1")

                assert len(caplog.records) == 2
                assert caplog.records[0].getMessage() == "start test"
                assert caplog.records[1].getMessage() == "inside subtest1"
            """
        )
        result = pytester.runpytest()
        result.stdout.fnmatch_lines(
            [
                "*1 passed*",
            ]
        )

    def test_no_logging(self, pytester: pytest.Pytester) -> None:
        pytester.makepyfile(
            """
            import logging

            def test(subtests):
                logging.info("start log line")

                with subtests.test("sub passing"):
                    logging.info("inside %s", "passing log line")

                with subtests.test("sub failing"):
                    logging.info("inside %s", "failing log line")
                    assert False

                logging.info("end log line")
            """
        )
        result = pytester.runpytest("-p no:logging")
        result.stdout.fnmatch_lines(
            [
                "*1 passed*",
            ]
        )
        result.stdout.no_fnmatch_line("*root:test_no_logging.py*log line*")


class TestDebugging:
    """Check --pdb support for subtests fixture and TestCase.subTest."""

    class _FakePdb:
        """
        Fake debugger class implementation that tracks which methods were called on it.
        """

        quitting: bool = False
        calls: list[str] = []

        def __init__(self, *_: object, **__: object) -> None:
            self.calls.append("init")

        def reset(self) -> None:
            self.calls.append("reset")

        def interaction(self, *_: object) -> None:
            self.calls.append("interaction")

    @pytest.fixture(autouse=True)
    def cleanup_calls(self) -> None:
        self._FakePdb.calls.clear()

    def test_pdb_fixture(
        self, pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        pytester.makepyfile(
            """
            def test(subtests):
                with subtests.test():
                    assert 0
            """
        )
        self.runpytest_and_check_pdb(pytester, monkeypatch)

    def test_pdb_unittest(
        self, pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        pytester.makepyfile(
            """
            from unittest import TestCase
            class Test(TestCase):
                def test(self):
                    with self.subTest():
                        assert 0
            """
        )
        self.runpytest_and_check_pdb(pytester, monkeypatch)

    def runpytest_and_check_pdb(
        self, pytester: pytest.Pytester, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        # Install the fake pdb implementation in pytest_subtests so we can reference
        # it in the command line (any module would do).
        import pytest_subtests

        monkeypatch.setattr(pytest_subtests, "_CustomPdb", self._FakePdb, raising=False)
        result = pytester.runpytest("--pdb", "--pdbcls=pytest_subtests:_CustomPdb")

        # Ensure pytest entered in debugging mode when encountering the failing
        # assert.
        result.stdout.fnmatch_lines("*entering PDB*")
        assert self._FakePdb.calls == ["init", "reset", "interaction"]


def test_exitfirst(pytester: pytest.Pytester) -> None:
    """
    Validate that when passing --exitfirst the test exits after the first failed subtest.
    """
    pytester.makepyfile(
        """
        def test_foo(subtests):
            with subtests.test("sub1"):
                assert False

            with subtests.test("sub2"):
                assert False
        """
    )
    result = pytester.runpytest("--exitfirst")
    assert result.parseoutcomes()["failed"] == 2
    result.stdout.fnmatch_lines(
        [
            "*[[]sub1[]] SUBFAIL test_exitfirst.py::test_foo - assert False*",
            "FAILED test_exitfirst.py::test_foo - assert False",
            "* stopping after 2 failures*",
        ],
        consecutive=True,
    )
    result.stdout.no_fnmatch_line("*sub2*")  # sub2 not executed.