test_formatting.py

import sys
from typing import NoReturn

import pytest
from _pytest.capture import CaptureFixture
from _pytest.fixtures import SubRequest
from _pytest.monkeypatch import MonkeyPatch

from exceptiongroup import ExceptionGroup


def raise_excgroup() -> NoReturn:
    exceptions = []
    try:
        raise ValueError("foo")
    except ValueError as exc:
        exceptions.append(exc)

    try:
        raise RuntimeError("bar")
    except RuntimeError as exc:
        exc.__notes__ = ["Note from bar handler"]
        exceptions.append(exc)

    exc = ExceptionGroup("test message", exceptions)
    exc.add_note("Displays notes attached to the group too")
    raise exc


@pytest.fixture(
    params=[
        pytest.param(True, id="patched"),
        pytest.param(
            False,
            id="unpatched",
            marks=[
                pytest.mark.skipif(
                    sys.version_info >= (3, 11),
                    reason="No patching is done on Python >= 3.11",
                )
            ],
        ),
    ],
)
def patched(request: SubRequest) -> bool:
    return request.param


@pytest.fixture(
    params=[pytest.param(False, id="newstyle"), pytest.param(True, id="oldstyle")]
)
def old_argstyle(request: SubRequest) -> bool:
    return request.param


def test_exceptionhook(capsys: CaptureFixture) -> None:
    try:
        raise_excgroup()
    except ExceptionGroup as exc:
        sys.excepthook(type(exc), exc, exc.__traceback__)

    local_lineno = test_exceptionhook.__code__.co_firstlineno
    lineno = raise_excgroup.__code__.co_firstlineno
    module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
    output = capsys.readouterr().err
    assert output == (
        f"""\
  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {local_lineno + 2}, in test_exceptionhook
  |     raise_excgroup()
  |   File "{__file__}", line {lineno + 15}, in raise_excgroup
  |     raise exc
  | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
  | Displays notes attached to the group too
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 3}, in raise_excgroup
    |     raise ValueError("foo")
    | ValueError: foo
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 8}, in raise_excgroup
    |     raise RuntimeError("bar")
    | RuntimeError: bar
    | Note from bar handler
    +------------------------------------
"""
    )


def test_exceptiongroup_as_cause(capsys: CaptureFixture) -> None:
    try:
        raise Exception() from ExceptionGroup("", (Exception(),))
    except Exception as exc:
        sys.excepthook(type(exc), exc, exc.__traceback__)

    lineno = test_exceptiongroup_as_cause.__code__.co_firstlineno
    module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
    output = capsys.readouterr().err
    assert output == (
        f"""\
  | {module_prefix}ExceptionGroup:  (1 sub-exception)
  +-+---------------- 1 ----------------
    | Exception
    +------------------------------------

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "{__file__}", line {lineno + 2}, in test_exceptiongroup_as_cause
    raise Exception() from ExceptionGroup("", (Exception(),))
Exception
"""
    )


def test_exceptiongroup_loop(capsys: CaptureFixture) -> None:
    e0 = Exception("e0")
    eg0 = ExceptionGroup("eg0", (e0,))
    eg1 = ExceptionGroup("eg1", (eg0,))

    try:
        raise eg0 from eg1
    except ExceptionGroup as exc:
        sys.excepthook(type(exc), exc, exc.__traceback__)

    lineno = test_exceptiongroup_loop.__code__.co_firstlineno + 6
    module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
    output = capsys.readouterr().err
    assert output == (
        f"""\
  | {module_prefix}ExceptionGroup: eg1 (1 sub-exception)
  +-+---------------- 1 ----------------
    | Exception Group Traceback (most recent call last):
    |   File "{__file__}", line {lineno}, in test_exceptiongroup_loop
    |     raise eg0 from eg1
    | {module_prefix}ExceptionGroup: eg0 (1 sub-exception)
    +-+---------------- 1 ----------------
      | Exception: e0
      +------------------------------------

The above exception was the direct cause of the following exception:

  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {lineno}, in test_exceptiongroup_loop
  |     raise eg0 from eg1
  | {module_prefix}ExceptionGroup: eg0 (1 sub-exception)
  +-+---------------- 1 ----------------
    | Exception: e0
    +------------------------------------
"""
    )


def test_exceptionhook_format_exception_only(capsys: CaptureFixture) -> None:
    try:
        raise_excgroup()
    except ExceptionGroup as exc:
        sys.excepthook(type(exc), exc, exc.__traceback__)

    local_lineno = test_exceptionhook_format_exception_only.__code__.co_firstlineno
    lineno = raise_excgroup.__code__.co_firstlineno
    module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
    output = capsys.readouterr().err
    assert output == (
        f"""\
  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {local_lineno + 2}, in \
test_exceptionhook_format_exception_only
  |     raise_excgroup()
  |   File "{__file__}", line {lineno + 15}, in raise_excgroup
  |     raise exc
  | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
  | Displays notes attached to the group too
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 3}, in raise_excgroup
    |     raise ValueError("foo")
    | ValueError: foo
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 8}, in raise_excgroup
    |     raise RuntimeError("bar")
    | RuntimeError: bar
    | Note from bar handler
    +------------------------------------
"""
    )


def test_formatting_syntax_error(capsys: CaptureFixture) -> None:
    try:
        exec("//serser")
    except SyntaxError as exc:
        sys.excepthook(type(exc), exc, exc.__traceback__)

    if sys.version_info >= (3, 10):
        underline = "\n    ^^"
    elif sys.version_info >= (3, 8):
        underline = "\n    ^"
    else:
        underline = "\n     ^"

    lineno = test_formatting_syntax_error.__code__.co_firstlineno
    output = capsys.readouterr().err
    assert output == (
        f"""\
Traceback (most recent call last):
  File "{__file__}", line {lineno + 2}, \
in test_formatting_syntax_error
    exec("//serser")
  File "<string>", line 1
    //serser{underline}
SyntaxError: invalid syntax
"""
    )


def test_format_exception(
    patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch
) -> None:
    if not patched:
        # Block monkey patching, then force the module to be re-imported
        del sys.modules["traceback"]
        del sys.modules["exceptiongroup"]
        del sys.modules["exceptiongroup._formatting"]
        monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args))

    from exceptiongroup import format_exception

    exceptions = []
    try:
        raise ValueError("foo")
    except ValueError as exc:
        exceptions.append(exc)

    try:
        raise RuntimeError("bar")
    except RuntimeError as exc:
        exc.__notes__ = ["Note from bar handler"]
        exceptions.append(exc)

    try:
        raise_excgroup()
    except ExceptionGroup as exc:
        if old_argstyle:
            lines = format_exception(type(exc), exc, exc.__traceback__)
        else:
            lines = format_exception(exc)

        local_lineno = test_format_exception.__code__.co_firstlineno
        lineno = raise_excgroup.__code__.co_firstlineno
        assert isinstance(lines, list)
        module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
        assert "".join(lines) == (
            f"""\
  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {local_lineno + 25}, in test_format_exception
  |     raise_excgroup()
  |   File "{__file__}", line {lineno + 15}, in raise_excgroup
  |     raise exc
  | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
  | Displays notes attached to the group too
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 3}, in raise_excgroup
    |     raise ValueError("foo")
    | ValueError: foo
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 8}, in raise_excgroup
    |     raise RuntimeError("bar")
    | RuntimeError: bar
    | Note from bar handler
    +------------------------------------
"""
        )


def test_format_exception_only(
    patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch
) -> None:
    if not patched:
        # Block monkey patching, then force the module to be re-imported
        del sys.modules["traceback"]
        del sys.modules["exceptiongroup"]
        del sys.modules["exceptiongroup._formatting"]
        monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args))

    from exceptiongroup import format_exception_only

    try:
        raise_excgroup()
    except ExceptionGroup as exc:
        if old_argstyle:
            output = format_exception_only(type(exc), exc)
        else:
            output = format_exception_only(exc)

        module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
        assert output == [
            f"{module_prefix}ExceptionGroup: test message (2 sub-exceptions)\n",
            "Displays notes attached to the group too\n",
        ]


def test_print_exception(
    patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture
) -> None:
    if not patched:
        # Block monkey patching, then force the module to be re-imported
        del sys.modules["traceback"]
        del sys.modules["exceptiongroup"]
        del sys.modules["exceptiongroup._formatting"]
        monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args))

    from exceptiongroup import print_exception

    try:
        raise_excgroup()
    except ExceptionGroup as exc:
        if old_argstyle:
            print_exception(type(exc), exc, exc.__traceback__)
        else:
            print_exception(exc)

        local_lineno = test_print_exception.__code__.co_firstlineno
        lineno = raise_excgroup.__code__.co_firstlineno
        module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
        output = capsys.readouterr().err
        assert output == (
            f"""\
  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {local_lineno + 13}, in test_print_exception
  |     raise_excgroup()
  |   File "{__file__}", line {lineno + 15}, in raise_excgroup
  |     raise exc
  | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
  | Displays notes attached to the group too
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 3}, in raise_excgroup
    |     raise ValueError("foo")
    | ValueError: foo
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 8}, in raise_excgroup
    |     raise RuntimeError("bar")
    | RuntimeError: bar
    | Note from bar handler
    +------------------------------------
"""
        )


def test_print_exc(
    patched: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture
) -> None:
    if not patched:
        # Block monkey patching, then force the module to be re-imported
        del sys.modules["traceback"]
        del sys.modules["exceptiongroup"]
        del sys.modules["exceptiongroup._formatting"]
        monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args))

    from exceptiongroup import print_exc

    try:
        raise_excgroup()
    except ExceptionGroup:
        print_exc()
        local_lineno = test_print_exc.__code__.co_firstlineno
        lineno = raise_excgroup.__code__.co_firstlineno
        module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup."
        output = capsys.readouterr().err
        assert output == (
            f"""\
  + Exception Group Traceback (most recent call last):
  |   File "{__file__}", line {local_lineno + 13}, in test_print_exc
  |     raise_excgroup()
  |   File "{__file__}", line {lineno + 15}, in raise_excgroup
  |     raise exc
  | {module_prefix}ExceptionGroup: test message (2 sub-exceptions)
  | Displays notes attached to the group too
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 3}, in raise_excgroup
    |     raise ValueError("foo")
    | ValueError: foo
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "{__file__}", line {lineno + 8}, in raise_excgroup
    |     raise RuntimeError("bar")
    | RuntimeError: bar
    | Note from bar handler
    +------------------------------------
"""
        )