test_assertrewrite.py

# mypy: allow-untyped-defs
from __future__ import annotations

import ast
from collections.abc import Generator
from collections.abc import Mapping
import dis
import errno
from functools import partial
import glob
import importlib
from importlib.util import source_hash
import inspect
import marshal
import os
from pathlib import Path
import py_compile
import re
import stat
import sys
import textwrap
from typing import cast
from unittest import mock
import zipfile

import _pytest._code
from _pytest._io.saferepr import DEFAULT_REPR_MAX_SIZE
from _pytest.assertion import util
from _pytest.assertion.rewrite import _get_assertion_exprs
from _pytest.assertion.rewrite import _get_maxsize_for_saferepr
from _pytest.assertion.rewrite import _saferepr
from _pytest.assertion.rewrite import AssertionRewritingHook
from _pytest.assertion.rewrite import get_cache_dir
from _pytest.assertion.rewrite import PYC_TAIL
from _pytest.assertion.rewrite import PYTEST_TAG
from _pytest.assertion.rewrite import rewrite_asserts
from _pytest.config import Config
from _pytest.config import ExitCode
from _pytest.pathlib import make_numbered_dir
from _pytest.pytester import Pytester
import pytest


def rewrite(src: str) -> ast.Module:
    tree = ast.parse(src)
    rewrite_asserts(tree, src.encode())
    return tree


def getmsg(
    f, extra_ns: Mapping[str, object] | None = None, *, must_pass: bool = False
) -> str | None:
    """Rewrite the assertions in f, run it, and get the failure message."""
    src = "\n".join(_pytest._code.Code.from_function(f).source().lines)
    mod = rewrite(src)
    code = compile(mod, "<test>", "exec")
    ns: dict[str, object] = {}
    if extra_ns is not None:
        ns.update(extra_ns)
    exec(code, ns)
    func = ns[f.__name__]
    try:
        func()  # type: ignore[operator]
    except AssertionError:
        if must_pass:
            pytest.fail("shouldn't have raised")
        s = str(sys.exc_info()[1])
        if not s.startswith("assert"):
            return "AssertionError: " + s
        return s
    else:
        if not must_pass:
            pytest.fail("function didn't raise at all")
        return None


class TestAssertionRewrite:
    def test_place_initial_imports(self) -> None:
        s = """'Doc string'\nother = stuff"""
        m = rewrite(s)
        assert isinstance(m.body[0], ast.Expr)
        for imp in m.body[1:3]:
            assert isinstance(imp, ast.Import)
            assert imp.lineno == 2
            assert imp.col_offset == 0
        assert isinstance(m.body[3], ast.Assign)
        s = """from __future__ import division\nother_stuff"""
        m = rewrite(s)
        assert isinstance(m.body[0], ast.ImportFrom)
        for imp in m.body[1:3]:
            assert isinstance(imp, ast.Import)
            assert imp.lineno == 2
            assert imp.col_offset == 0
        assert isinstance(m.body[3], ast.Expr)
        s = """'doc string'\nfrom __future__ import division"""
        m = rewrite(s)
        assert isinstance(m.body[0], ast.Expr)
        assert isinstance(m.body[1], ast.ImportFrom)
        for imp in m.body[2:4]:
            assert isinstance(imp, ast.Import)
            assert imp.lineno == 2
            assert imp.col_offset == 0
        s = """'doc string'\nfrom __future__ import division\nother"""
        m = rewrite(s)
        assert isinstance(m.body[0], ast.Expr)
        assert isinstance(m.body[1], ast.ImportFrom)
        for imp in m.body[2:4]:
            assert isinstance(imp, ast.Import)
            assert imp.lineno == 3
            assert imp.col_offset == 0
        assert isinstance(m.body[4], ast.Expr)
        s = """from . import relative\nother_stuff"""
        m = rewrite(s)
        for imp in m.body[:2]:
            assert isinstance(imp, ast.Import)
            assert imp.lineno == 1
            assert imp.col_offset == 0
        assert isinstance(m.body[3], ast.Expr)

    def test_location_is_set(self) -> None:
        s = textwrap.dedent(
            """

        assert False, (

            "Ouch"
          )

        """
        )
        m = rewrite(s)
        for node in m.body:
            if isinstance(node, ast.Import):
                continue
            for n in [node, *ast.iter_child_nodes(node)]:
                assert isinstance(n, ast.stmt | ast.expr)
                for location in [
                    (n.lineno, n.col_offset),
                    (n.end_lineno, n.end_col_offset),
                ]:
                    assert (3, 0) <= location <= (6, 3)

    def test_positions_are_preserved(self) -> None:
        """Ensure AST positions are preserved during rewriting (#12818)."""

        def preserved(code: str) -> None:
            s = textwrap.dedent(code)
            locations = []

            def loc(msg: str | None = None) -> None:
                frame = inspect.currentframe()
                assert frame
                frame = frame.f_back
                assert frame
                frame = frame.f_back
                assert frame

                offset = frame.f_lasti

                instructions = {i.offset: i for i in dis.get_instructions(frame.f_code)}

                # skip CACHE instructions
                while offset not in instructions and offset >= 0:
                    offset -= 1

                instruction = instructions[offset]
                if sys.version_info >= (3, 11):
                    position = instruction.positions
                else:
                    position = instruction.starts_line

                locations.append((msg, instruction.opname, position))

            globals = {"loc": loc}

            m = rewrite(s)
            mod = compile(m, "<string>", "exec")
            exec(mod, globals, globals)
            transformed_locations = locations
            locations = []

            mod = compile(s, "<string>", "exec")
            exec(mod, globals, globals)
            original_locations = locations

            assert len(original_locations) > 0
            assert original_locations == transformed_locations

        preserved("""
            def f():
                loc()
                return 8

            assert f() in [8]
            assert (f()
                    in
                    [8])
        """)

        preserved("""
            class T:
                def __init__(self):
                    loc("init")
                def __getitem__(self,index):
                    loc("getitem")
                    return index

            assert T()[5] == 5
            assert (T
                    ()
                    [5]
                    ==
                    5)
        """)

        for name, op in [
            ("pos", "+"),
            ("neg", "-"),
            ("invert", "~"),
        ]:
            preserved(f"""
                class T:
                    def __{name}__(self):
                        loc("{name}")
                        return "{name}"

                assert {op}T() == "{name}"
                assert ({op}
                        T
                        ()
                        ==
                        "{name}")
            """)

        for name, op in [
            ("add", "+"),
            ("sub", "-"),
            ("mul", "*"),
            ("truediv", "/"),
            ("floordiv", "//"),
            ("mod", "%"),
            ("pow", "**"),
            ("lshift", "<<"),
            ("rshift", ">>"),
            ("or", "|"),
            ("xor", "^"),
            ("and", "&"),
            ("matmul", "@"),
        ]:
            preserved(f"""
                class T:
                    def __{name}__(self,other):
                        loc("{name}")
                        return other

                    def __r{name}__(self,other):
                        loc("r{name}")
                        return other

                assert T() {op} 2 == 2
                assert 2 {op} T() == 2

                assert (T
                        ()
                        {op}
                        2
                        ==
                        2)

                assert (2
                        {op}
                        T
                        ()
                        ==
                        2)
        """)

        for name, op in [
            ("eq", "=="),
            ("ne", "!="),
            ("lt", "<"),
            ("le", "<="),
            ("gt", ">"),
            ("ge", ">="),
        ]:
            preserved(f"""
                class T:
                    def __{name}__(self,other):
                        loc()
                        return True

                assert  T() {op} 5
                assert  (T
                        ()
                        {op}
                        5)
        """)

        for name, op in [
            ("eq", "=="),
            ("ne", "!="),
            ("lt", ">"),
            ("le", ">="),
            ("gt", "<"),
            ("ge", "<="),
            ("contains", "in"),
        ]:
            preserved(f"""
                class T:
                    def __{name}__(self,other):
                        loc()
                        return True

                assert  5 {op} T()
                assert  (5
                         {op}
                         T
                         ())
        """)

        preserved("""
            def func(value):
                loc("func")
                return value

            class T:
                def __iter__(self):
                    loc("iter")
                    return iter([5])

            assert  func(*T()) == 5
        """)

        preserved("""
            class T:
                def __getattr__(self,name):
                    loc()
                    return name

            assert  T().attr == "attr"
        """)

    def test_dont_rewrite(self) -> None:
        s = """'PYTEST_DONT_REWRITE'\nassert 14"""
        m = rewrite(s)
        assert len(m.body) == 2
        assert isinstance(m.body[1], ast.Assert)
        assert m.body[1].msg is None

    def test_dont_rewrite_plugin(self, pytester: Pytester) -> None:
        contents = {
            "conftest.py": "pytest_plugins = 'plugin'; import plugin",
            "plugin.py": "'PYTEST_DONT_REWRITE'",
            "test_foo.py": "def test_foo(): pass",
        }
        pytester.makepyfile(**contents)
        result = pytester.runpytest_subprocess()
        assert "warning" not in "".join(result.outlines)

    def test_rewrites_plugin_as_a_package(self, pytester: Pytester) -> None:
        pkgdir = pytester.mkpydir("plugin")
        pkgdir.joinpath("__init__.py").write_text(
            "import pytest\n"
            "@pytest.fixture\n"
            "def special_asserter():\n"
            "    def special_assert(x, y):\n"
            "        assert x == y\n"
            "    return special_assert\n",
            encoding="utf-8",
        )
        pytester.makeconftest('pytest_plugins = ["plugin"]')
        pytester.makepyfile("def test(special_asserter): special_asserter(1, 2)\n")
        result = pytester.runpytest()
        result.stdout.fnmatch_lines(["*assert 1 == 2*"])

    def test_honors_pep_235(self, pytester: Pytester, monkeypatch) -> None:
        # note: couldn't make it fail on macos with a single `sys.path` entry
        # note: these modules are named `test_*` to trigger rewriting
        pytester.makepyfile(test_y="x = 1")
        xdir = pytester.mkdir("x")
        pytester.mkpydir(str(xdir.joinpath("test_Y")))
        xdir.joinpath("test_Y").joinpath("__init__.py").write_text(
            "x = 2", encoding="utf-8"
        )
        pytester.makepyfile(
            "import test_y\n"
            "import test_Y\n"
            "def test():\n"
            "    assert test_y.x == 1\n"
            "    assert test_Y.x == 2\n"
        )
        monkeypatch.syspath_prepend(str(xdir))
        pytester.runpytest().assert_outcomes(passed=1)

    def test_name(self, request) -> None:
        def f1() -> None:
            assert False

        assert getmsg(f1) == "assert False"

        def f2() -> None:
            f = False
            assert f

        assert getmsg(f2) == "assert False"

        def f3() -> None:
            assert a_global  # type: ignore[name-defined] # noqa: F821

        assert getmsg(f3, {"a_global": False}) == "assert False"

        def f4() -> None:
            assert sys == 42  # type: ignore[comparison-overlap]

        msg = getmsg(f4, {"sys": sys})
        assert msg == "assert sys == 42"

        def f5() -> None:
            assert cls == 42  # type: ignore[name-defined]  # noqa: F821

        class X:
            pass

        msg = getmsg(f5, {"cls": X})
        assert msg is not None
        lines = msg.splitlines()
        assert lines == ["assert cls == 42"]

    def test_assertrepr_compare_same_width(self, request) -> None:
        """Should use same width/truncation with same initial width."""

        def f() -> None:
            assert "1234567890" * 5 + "A" == "1234567890" * 5 + "B"

        msg = getmsg(f)
        assert msg is not None
        line = msg.splitlines()[0]
        if request.config.getoption("verbose") > 1:
            assert line == (
                "assert '12345678901234567890123456789012345678901234567890A' "
                "== '12345678901234567890123456789012345678901234567890B'"
            )
        else:
            assert line == (
                "assert '123456789012...901234567890A' "
                "== '123456789012...901234567890B'"
            )

    def test_dont_rewrite_if_hasattr_fails(self, request) -> None:
        class Y:
            """A class whose getattr fails, but not with `AttributeError`."""

            def __getattr__(self, attribute_name):
                raise KeyError()

            def __repr__(self) -> str:
                return "Y"

            def __init__(self) -> None:
                self.foo = 3

        def f() -> None:
            assert cls().foo == 2  # type: ignore[name-defined] # noqa: F821

        # XXX: looks like the "where" should also be there in verbose mode?!
        msg = getmsg(f, {"cls": Y})
        assert msg is not None
        lines = msg.splitlines()
        assert lines == [
            "assert 3 == 2",
            " +  where 3 = Y.foo",
            " +    where Y = cls()",
        ]

    def test_assert_already_has_message(self) -> None:
        def f():
            assert False, "something bad!"

        assert getmsg(f) == "AssertionError: something bad!\nassert False"

    def test_assertion_message(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo():
                assert 1 == 2, "The failure message"
        """
        )
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(
            ["*AssertionError*The failure message*", "*assert 1 == 2*"]
        )

    def test_assertion_message_multiline(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo():
                assert 1 == 2, "A multiline\\nfailure message"
        """
        )
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(
            ["*AssertionError*A multiline*", "*failure message*", "*assert 1 == 2*"]
        )

    def test_assertion_message_tuple(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo():
                assert 1 == 2, (1, 2)
        """
        )
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines([f"*AssertionError*{(1, 2)!r}*", "*assert 1 == 2*"])

    def test_assertion_message_expr(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo():
                assert 1 == 2, 1 + 2
        """
        )
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(["*AssertionError*3*", "*assert 1 == 2*"])

    def test_assertion_message_escape(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            def test_foo():
                assert 1 == 2, 'To be escaped: %'
        """
        )
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(
            ["*AssertionError: To be escaped: %", "*assert 1 == 2"]
        )

    def test_assertion_messages_bytes(self, pytester: Pytester) -> None:
        pytester.makepyfile("def test_bytes_assertion():\n    assert False, b'ohai!'\n")
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(["*AssertionError: b'ohai!'", "*assert False"])

    def test_assertion_message_verbosity(self, pytester: Pytester) -> None:
        """
        Obey verbosity levels when printing the "message" part of assertions, when they are
        non-strings (#6682).
        """
        pytester.makepyfile(
            """
            class LongRepr:

                def __repr__(self):
                    return "A" * 500

            def test_assertion_verbosity():
                assert False, LongRepr()
            """
        )
        # Normal verbosity: assertion message gets abbreviated.
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.re_match_lines(
            [r".*AssertionError: A+\.\.\.A+$", ".*assert False"]
        )

        # High-verbosity: do not abbreviate the assertion message.
        result = pytester.runpytest("-vv")
        assert result.ret == 1
        result.stdout.re_match_lines([r".*AssertionError: A+$", ".*assert False"])

    def test_assertion_message_verbosity_collection(self, pytester: Pytester) -> None:
        """
        With -vv, the "message" part of assertions must not elide collection
        elements with "..." either (#12307).
        """
        pytester.makepyfile(
            """
            def test_assertion_verbosity_collection():
                assert False, list(range(100))
            """
        )
        # Normal verbosity: collection elements are elided.
        result = pytester.runpytest()
        assert result.ret == 1
        result.stdout.fnmatch_lines(["*AssertionError: [[]0, 1, 2, 3, 4, 5, ...*"])

        # High-verbosity: show the collection in full.
        result = pytester.runpytest("-vv")
        assert result.ret == 1
        result.stdout.fnmatch_lines(["*AssertionError: [[]0, 1, 2,*98, 99[]]*"])
        result.stdout.no_fnmatch_line("*AssertionError: *...*")

    def test_boolop(self) -> None:
        def f1() -> None:
            f = g = False
            assert f and g

        assert getmsg(f1) == "assert (False)"

        def f2() -> None:
            f = True
            g = False
            assert f and g

        assert getmsg(f2) == "assert (True and False)"

        def f3() -> None:
            f = False
            g = True
            assert f and g

        assert getmsg(f3) == "assert (False)"

        def f4() -> None:
            f = g = False
            assert f or g

        assert getmsg(f4) == "assert (False or False)"

        def f5() -> None:
            f = g = False
            assert not f and not g

        getmsg(f5, must_pass=True)

        def x() -> bool:
            return False

        def f6() -> None:
            assert x() and x()

        assert (
            getmsg(f6, {"x": x})
            == """assert (False)
 +  where False = x()"""
        )

        def f7() -> None:
            assert False or x()

        assert (
            getmsg(f7, {"x": x})
            == """assert (False or False)
 +  where False = x()"""
        )

        def f8() -> None:
            assert 1 in {} and 2 in {}

        assert getmsg(f8) == "assert (1 in {})"

        def f9() -> None:
            x = 1
            y = 2
            assert x in {1: None} and y in {}

        assert getmsg(f9) == "assert (1 in {1: None} and 2 in {})"

        def f10() -> None:
            f = True
            g = False
            assert f or g

        getmsg(f10, must_pass=True)

        def f11() -> None:
            f = g = h = lambda: True
            assert f() and g() and h()

        getmsg(f11, must_pass=True)

    def test_short_circuit_evaluation(self) -> None:
        def f1() -> None:  # pragma: no cover
            assert True or explode  # type: ignore[name-defined,unreachable] # noqa: F821,SIM222

        getmsg(f1, must_pass=True)

        def f2() -> None:
            x = 1
            assert x == 1 or x == 2  # noqa: PLR1714

        getmsg(f2, must_pass=True)

    def test_unary_op(self) -> None:
        def f1() -> None:
            x = True
            assert not x

        assert getmsg(f1) == "assert not True"

        def f2() -> None:
            x = 0
            assert ~x + 1

        assert getmsg(f2) == "assert (~0 + 1)"

        def f3() -> None:
            x = 3
            assert -x + x

        assert getmsg(f3) == "assert (-3 + 3)"

        def f4() -> None:
            x = 0
            assert +x + x

        assert getmsg(f4) == "assert (+0 + 0)"

    def test_binary_op(self) -> None:
        def f1() -> None:
            x = 1
            y = -1
            assert x + y

        assert getmsg(f1) == "assert (1 + -1)"

        def f2() -> None:
            assert not 5 % 4

        assert getmsg(f2) == "assert not (5 % 4)"

    def test_boolop_percent(self) -> None:
        def f1() -> None:  # pragma: no cover
            assert 3 % 2 and False  # noqa: SIM223

        assert getmsg(f1) == "assert ((3 % 2) and False)"

        def f2() -> None:
            assert False or 4 % 2

        assert getmsg(f2) == "assert (False or (4 % 2))"

    def test_at_operator_issue1290(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """
            class Matrix(object):
                def __init__(self, num):
                    self.num = num
                def __matmul__(self, other):
                    return self.num * other.num

            def test_multmat_operator():
                assert Matrix(2) @ Matrix(3) == 6"""
        )
        pytester.runpytest().assert_outcomes(passed=1)

    def test_starred_with_side_effect(self, pytester: Pytester) -> None:
        """See #4412"""
        pytester.makepyfile(
            """\
            def test():
                f = lambda x: x
                x = iter([1, 2, 3])
                assert 2 * next(x) == f(*[next(x)])
            """
        )
        pytester.runpytest().assert_outcomes(passed=1)

    def test_call(self) -> None:
        def g(a=42, *args, **kwargs) -> bool:
            return False

        ns = {"g": g}

        def f1() -> None:
            assert g()

        assert (
            getmsg(f1, ns)
            == """assert False
 +  where False = g()"""
        )

        def f2() -> None:
            assert g(1)

        assert (
            getmsg(f2, ns)
            == """assert False
 +  where False = g(1)"""
        )

        def f3() -> None:
            assert g(1, 2)

        assert (
            getmsg(f3, ns)
            == """assert False
 +  where False = g(1, 2)"""
        )

        def f4() -> None:
            assert g(1, g=42)

        assert (
            getmsg(f4, ns)
            == """assert False
 +  where False = g(1, g=42)"""
        )

        def f5() -> None:
            assert g(1, 3, g=23)

        assert (
            getmsg(f5, ns)
            == """assert False
 +  where False = g(1, 3, g=23)"""
        )

        def f6() -> None:
            seq = [1, 2, 3]
            assert g(*seq)

        assert (
            getmsg(f6, ns)
            == """assert False
 +  where False = g(*[1, 2, 3])"""
        )

        def f7() -> None:
            x = "a"
            assert g(**{x: 2})

        assert (
            getmsg(f7, ns)
            == """assert False
 +  where False = g(**{'a': 2})"""
        )

    def test_attribute(self) -> None:
        class X:
            g = 3

        ns = {"x": X}

        def f1() -> None:
            assert not x.g  # type: ignore[name-defined] # noqa: F821

        assert (
            getmsg(f1, ns)
            == """assert not 3
 +  where 3 = x.g"""
        )

        def f2() -> None:
            x.a = False  # type: ignore[name-defined] # noqa: F821
            assert x.a  # type: ignore[name-defined] # noqa: F821

        assert (
            getmsg(f2, ns)
            == """assert False
 +  where False = x.a"""
        )

    def test_comparisons(self) -> None:
        def f1() -> None:
            a, b = range(2)
            assert b < a

        assert getmsg(f1) == """assert 1 < 0"""

        def f2() -> None:
            a, b, c = range(3)
            assert a > b > c

        assert getmsg(f2) == """assert 0 > 1"""

        def f3() -> None:
            a, b, c = range(3)
            assert a < b > c

        assert getmsg(f3) == """assert 1 > 2"""

        def f4() -> None:
            a, b, c = range(3)
            assert a < b <= c

        getmsg(f4, must_pass=True)

        def f5() -> None:
            a, b, c = range(3)
            assert a < b
            assert b < c

        getmsg(f5, must_pass=True)

    def test_len(self, request) -> None:
        def f():
            values = list(range(10))
            assert len(values) == 11

        msg = getmsg(f)
        assert msg == "assert 10 == 11\n +  where 10 = len([0, 1, 2, 3, 4, 5, ...])"

    def test_custom_reprcompare(self, monkeypatch) -> None:
        def my_reprcompare1(op, left, right) -> str:
            return "42"

        monkeypatch.setattr(util, "_reprcompare", my_reprcompare1)

        def f1() -> None:
            assert 42 < 3

        assert getmsg(f1) == "assert 42"

        def my_reprcompare2(op, left, right) -> str:
            return f"{left} {op} {right}"

        monkeypatch.setattr(util, "_reprcompare", my_reprcompare2)

        def f2() -> None:
            assert 1 < 3 < 5 <= 4 < 7

        assert getmsg(f2) == "assert 5 <= 4"

    def test_assert_raising__bool__in_comparison(self) -> None:
        def f() -> None:
            class A:
                def __bool__(self):
                    raise ValueError(42)

                def __lt__(self, other):
                    return A()

                def __repr__(self):
                    return "<MY42 object>"

            def myany(x) -> bool:
                return False

            assert myany(A() < 0)

        msg = getmsg(f)
        assert msg is not None
        assert "<MY42 object> < 0" in msg

    def test_assert_handling_raise_in__iter__(self, pytester: Pytester) -> None:
        pytester.makepyfile(
            """\
            class A:
                def __iter__(self):
                    raise ValueError()

                def __eq__(self, o: object) -> bool:
                    return self is o

                def __repr__(self):
                    return "<A object>"

            assert A() == A()
            """
        )
        result = pytester.runpytest()
        result.stdout.fnmatch_lines(["*E*assert <A object> == <A object>"])

    def test_formatchar(self) -> None:
        def f() -> None:
            assert "%test" == "test"  # type: ignore[comparison-overlap]

        msg = getmsg(f)
        assert msg is not None
        assert msg.startswith("assert '%test' == 'test'")

    def test_custom_repr(self, request) -> None:
        def f() -> None:
            class Foo:
                a = 1

                def __repr__(self):
                    return "\n{ \n~ \n}"

            f = Foo()
            assert 0 == f.a

        msg = getmsg(f)
        assert msg is not None
        lines = util._format_lines([msg])
        assert lines == ["assert 0 == 1\n +  where 1 = \\n{ \\n~ \\n}.a"]

    def test_custom_repr_non_ascii(self) -> None:
        def f() -> None:
            class A:
                name = "ä"

                def __repr__(self):
                    return self.name.encode("UTF-8")  # only legal in python2

            a = A()
            assert not a.name

        msg = getmsg(f)
        assert msg is not None
        assert "UnicodeDecodeError" not in msg
        assert "UnicodeEncodeError" not in msg