Have pytest.raises match against exception __notes__ (#11227)

The doctest is skipped because add_note is only available in 3.11,

Closes #11223

Author: ivirshup

AUTHORS

@@ -168,6 +168,7 @@ Ian Bicking
 Ian Lesperance
 Ilya Konstantinov
 Ionuț Turturică
+Isaac Virshup
 Itxaso Aizpurua
 Iwan Briquemont
 Jaap Broekhuizen

changelog/11227.improvement.rst

@@ -0,0 +1 @@
+Allow :func:`pytest.raises` ``match`` argument to match against `PEP-678 <https://peps.python.org/pep-0678/>` ``__notes__``.

src/_pytest/_code/code.py

@@ -704,7 +704,12 @@ def match(self, regexp: Union[str, Pattern[str]]) -> "Literal[True]":
         If it matches `True` is returned, otherwise an `AssertionError` is raised.
         """
         __tracebackhide__ = True
-        value = str(self.value)
+        value = "\n".join(
+            [
+                str(self.value),
+                *getattr(self.value, "__notes__", []),
+            ]
+        )
         msg = f"Regex pattern did not match.\n Regex: {regexp!r}\n Input: {value!r}"
         if regexp == value:
             msg += "\n Did you mean to `re.escape()` the regex?"

src/_pytest/python_api.py

@@ -843,6 +843,14 @@ def raises(  # noqa: F811
         >>> with pytest.raises(ValueError, match=r'must be \d+$'):
         ...     raise ValueError("value must be 42")
 
+    The ``match`` argument searches the formatted exception string, which includes any
+    `PEP-678 <https://peps.python.org/pep-0678/>` ``__notes__``:
+
+        >>> with pytest.raises(ValueError, match=r'had a note added'):  # doctest: +SKIP
+        ...    e = ValueError("value must be 42")
+        ...    e.add_note("had a note added")
+        ...    raise e
+
     The context manager produces an :class:`ExceptionInfo` object which can be used to inspect the
     details of the captured exception::
 

testing/code/test_excinfo.py

@@ -1,15 +1,15 @@
+from __future__ import annotations
+
 import importlib
 import io
 import operator
 import queue
+import re
 import sys
 import textwrap
 from pathlib import Path
 from typing import Any
-from typing import Dict
-from typing import Tuple
 from typing import TYPE_CHECKING
-from typing import Union
 
 import _pytest._code
 import pytest
@@ -801,7 +801,7 @@ def entry():
         )
         excinfo = pytest.raises(ValueError, mod.entry)
 
-        styles: Tuple[_TracebackStyle, ...] = ("long", "short")
+        styles: tuple[_TracebackStyle, ...] = ("long", "short")
         for style in styles:
             p = FormattedExcinfo(style=style)
             reprtb = p.repr_traceback(excinfo)
@@ -928,7 +928,7 @@ def entry():
         )
         excinfo = pytest.raises(ValueError, mod.entry)
 
-        styles: Tuple[_TracebackStyle, ...] = ("short", "long", "no")
+        styles: tuple[_TracebackStyle, ...] = ("short", "long", "no")
         for style in styles:
             for showlocals in (True, False):
                 repr = excinfo.getrepr(style=style, showlocals=showlocals)
@@ -1090,7 +1090,7 @@ def f():
             for funcargs in (True, False)
         ],
     )
-    def test_format_excinfo(self, reproptions: Dict[str, Any]) -> None:
+    def test_format_excinfo(self, reproptions: dict[str, Any]) -> None:
         def bar():
             assert False, "some error"
 
@@ -1398,7 +1398,7 @@ def f():
 @pytest.mark.parametrize("encoding", [None, "utf8", "utf16"])
 def test_repr_traceback_with_unicode(style, encoding):
     if encoding is None:
-        msg: Union[str, bytes] = "☹"
+        msg: str | bytes = "☹"
     else:
         msg = "☹".encode(encoding)
     try:
@@ -1648,3 +1648,51 @@ def test():
         ],
         consecutive=True,
     )
+
+
+def add_note(err: BaseException, msg: str) -> None:
+    """Adds a note to an exception inplace."""
+    if sys.version_info < (3, 11):
+        err.__notes__ = getattr(err, "__notes__", []) + [msg]  # type: ignore[attr-defined]
+    else:
+        err.add_note(msg)
+
+
+@pytest.mark.parametrize(
+    "error,notes,match",
+    [
+        (Exception("test"), [], "test"),
+        (AssertionError("foo"), ["bar"], "bar"),
+        (AssertionError("foo"), ["bar", "baz"], "bar"),
+        (AssertionError("foo"), ["bar", "baz"], "baz"),
+        (ValueError("foo"), ["bar", "baz"], re.compile(r"bar\nbaz", re.MULTILINE)),
+        (ValueError("foo"), ["bar", "baz"], re.compile(r"BAZ", re.IGNORECASE)),
+    ],
+)
+def test_check_error_notes_success(
+    error: Exception, notes: list[str], match: str
+) -> None:
+    for note in notes:
+        add_note(error, note)
+
+    with pytest.raises(Exception, match=match):
+        raise error
+
+
+@pytest.mark.parametrize(
+    "error, notes, match",
+    [
+        (Exception("test"), [], "foo"),
+        (AssertionError("foo"), ["bar"], "baz"),
+        (AssertionError("foo"), ["bar"], "foo\nbaz"),
+    ],
+)
+def test_check_error_notes_failure(
+    error: Exception, notes: list[str], match: str
+) -> None:
+    for note in notes:
+        add_note(error, note)
+
+    with pytest.raises(AssertionError):
+        with pytest.raises(type(error), match=match):
+            raise error