Add OuputVerbosity and use it in assertions

AUTHORS

@@ -291,6 +291,7 @@ Ondřej Súkup
 Oscar Benjamin
 Parth Patel
 Patrick Hayes
+Patrick Lannigan
 Paul Müller
 Paul Reece
 Pauli Virtanen

changelog/11387.feature.rst

@@ -0,0 +1 @@
+:confval:`verbosity_assertions` option added to be able to control assertion output independent of the application wide verbosity level.

doc/en/how-to/output.rst

@@ -270,6 +270,16 @@ situations, for example you are shown even fixtures that start with ``_`` if you
 Using higher verbosity levels (``-vvv``, ``-vvvv``, ...) is supported, but has no effect in pytest itself at the moment,
 however some plugins might make use of higher verbosity.
 
+Fine gain verbosity
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In addition to specifying the application wide verbosity level, it is possible to control specific aspects independently.
+This is done by setting a verbosity level in the configuration file for the specific aspect of the output.
+
+``verbosity_assertions``: Controls how verbose the assertion output should be when pytest is executed. A value of ``2``
+would have the same output as the previous example, but each test inside the file is shown by a single character in the
+output.
+
 .. _`pytest.detailed_failed_tests_usage`:
 
 Producing a detailed summary report

doc/en/reference/reference.rst

@@ -1819,6 +1819,19 @@ passed multiple times. The expected format is ``name=value``. For example::
             clean_db
 
 
+.. confval:: verbosity_assertions
+
+    Set a verbosity level specifically for assertion related output, overriding the application wide level.
+
+
+    .. code-block:: ini
+
+        [pytest]
+        verbosity_assertions = 2
+
+    Defaults to application wide verbosity level.
+
+
 .. confval:: xfail_strict
 
     If set to ``True``, tests marked with ``@pytest.mark.xfail`` that actually succeed will by default fail the

src/_pytest/assertion/__init__.py

@@ -12,6 +12,7 @@ from _pytest.assertion import util
 from _pytest.assertion.rewrite import assertstate_key
 from _pytest.config import Config
 from _pytest.config import hookimpl
+from _pytest.config import OutputVerbosity
 from _pytest.config.argparsing import Parser
 from _pytest.nodes import Item
 
@@ -42,6 +43,14 @@ def pytest_addoption(parser: Parser) -> None:
         help="Enables the pytest_assertion_pass hook. "
         "Make sure to delete any previously generated pyc cache files.",
     )
+    OutputVerbosity.add_ini(
+        parser,
+        "assertions",
+        help=(
+            "Specify a verbosity level for assertions, overriding the main level. "
+            "Higher levels will provide more a more detailed explanation when an assertion fails."
+        ),
+    )
 
 
 def register_assert_rewrite(*names: str) -> None:

src/_pytest/assertion/truncate.py

@@ -1,7 +1,7 @@
 """Utilities for truncating assertion output.
 
 Current default behaviour is to truncate assertion explanations at
-~8 terminal lines, unless running in "-vv" mode or running on CI.
+terminal lines, unless running with a verbosity level of at least 2 or running on CI.
 """
 from typing import List
 from typing import Optional
@@ -26,7 +26,7 @@ def truncate_if_required(
 
 def _should_truncate_item(item: Item) -> bool:
     """Whether or not this test item is eligible for truncation."""
-    verbose = item.config.option.verbose
+    verbose = item.config.output_verbosity.verbosity_for("assertions")
     return verbose < 2 and not util.running_on_ci()
 
 

src/_pytest/assertion/util.py

@@ -161,7 +161,7 @@ def assertrepr_compare(
     config, op: str, left: Any, right: Any, use_ascii: bool = False
 ) -> Optional[List[str]]:
     """Return specialised explanations for some operators/operands."""
-    verbose = config.getoption("verbose")
+    verbose = config.output_verbosity.verbosity_for("assertions")
 
     # Strings which normalize equal are often hard to distinguish when printed; use ascii() to make this easier.
     # See issue #3246.

src/_pytest/config/__init__.py

@@ -69,7 +69,7 @@ from _pytest.warning_types import warn_explicit_for
 if TYPE_CHECKING:
     from _pytest._code.code import _TracebackStyle
     from _pytest.terminal import TerminalReporter
-    from .argparsing import Argument
+    from .argparsing import Argument, Parser
 
 
 _PluggyPlugin = object
@@ -1020,6 +1020,7 @@ class Config:
         )
         self.args_source = Config.ArgsSource.ARGS
         self.args: List[str] = []
+        self.output_verbosity = OutputVerbosity(self)
 
         if TYPE_CHECKING:
             from _pytest.cacheprovider import Cache
@@ -1662,6 +1663,54 @@ class Config:
             )
 
 
+class OutputVerbosity:
+    DEFAULT = "auto"
+    _option_name_fmt = "verbosity_{}"
+
+    def __init__(self, config: Config) -> None:
+        self._config = config
+
+    @property
+    def verbose(self) -> int:
+        """Application wide verbosity level."""
+        return cast(int, self._config.option.verbose)
+
+    def verbosity_for(self, output_type: str) -> int:
+        """Return verbosity level for the given output type.
+
+        :param output_type: Name of the output type.
+
+        If the level is not configured, the value of ``config.option.verbose``.
+        """
+        level = self._config.getini(OutputVerbosity._ini_name(output_type))
+
+        if level == OutputVerbosity.DEFAULT:
+            return self.verbose
+        return int(level)
+
+    @staticmethod
+    def _ini_name(output_type: str) -> str:
+        return f"verbosity_{output_type}"
+
+    @staticmethod
+    def add_ini(parser: "Parser", output_type: str, help: str) -> None:
+        """Add a output verbosity configuration option for the given output type.
+
+        :param parser: Parser for command line arguments and ini-file values.
+        :param output_type: Name of the output type.
+        :param help: Description of the output this type controls.
+
+        The value should be retrieved via a call to
+        :py:func:`config.output_verbosity.verbosity_for(name) <pytest.OutputVerbosity.verbosity_for>`.
+        """
+        parser.addini(
+            OutputVerbosity._ini_name(output_type),
+            help=help,
+            type="string",
+            default=OutputVerbosity.DEFAULT,
+        )
+
+
 def _assertion_supported() -> bool:
     try:
         assert False

src/pytest/__init__.py

@@ -15,6 +15,7 @@ from _pytest.config import ExitCode
 from _pytest.config import hookimpl
 from _pytest.config import hookspec
 from _pytest.config import main
+from _pytest.config import OutputVerbosity
 from _pytest.config import PytestPluginManager
 from _pytest.config import UsageError
 from _pytest.config.argparsing import OptionGroup
@@ -126,6 +127,7 @@ __all__ = [
     "Module",
     "MonkeyPatch",
     "OptionGroup",
+    "OutputVerbosity",
     "Package",
     "param",
     "Parser",

testing/test_assertion.py

@@ -17,12 +17,23 @@ from _pytest.monkeypatch import MonkeyPatch
 from _pytest.pytester import Pytester
 
 
-def mock_config(verbose=0):
-    class Config:
-        def getoption(self, name):
-            if name == "verbose":
+def mock_config(verbose: int = 0, assertion_override: Optional[int] = None):
+    class OutputVerbosity:
+        @property
+        def verbose(self) -> int:
+            return verbose
+
+        def verbosity_for(self, output_type: str) -> int:
+            if output_type == "assertions":
+                if assertion_override is not None:
+                    return assertion_override
                 return verbose
-            raise KeyError("Not mocked out: %s" % name)
+
+            raise KeyError("Not mocked out: %s" % output_type)
+
+    class Config:
+        def __init__(self) -> None:
+            self.output_verbosity = OutputVerbosity()
 
     return Config()
 

testing/test_config.py

@@ -20,7 +20,9 @@ from _pytest.config import _strtobool
 from _pytest.config import Config
 from _pytest.config import ConftestImportFailure
 from _pytest.config import ExitCode
+from _pytest.config import OutputVerbosity
 from _pytest.config import parse_warning_filter
+from _pytest.config.argparsing import Parser
 from _pytest.config.exceptions import UsageError
 from _pytest.config.findpaths import determine_setup
 from _pytest.config.findpaths import get_common_ancestor
@@ -2181,3 +2183,74 @@ class TestDebugOptions:
                 "*Default: pytestdebug.log.",
             ]
         )
+
+
+class TestOutputVerbosity:
+    SOME_OUTPUT_TYPE = "foo"
+    SOME_OUTPUT_VERBOSITY_LEVEL = 5
+
+    class VerbosityIni:
+        def pytest_addoption(self, parser: Parser) -> None:
+            OutputVerbosity.add_ini(
+                parser, TestOutputVerbosity.SOME_OUTPUT_TYPE, help="some help text"
+            )
+
+    def test_verbose_matches_option_verbose(
+        self, pytester: Pytester, tmp_path: Path
+    ) -> None:
+        tmp_path.joinpath("pytest.ini").write_text(
+            textwrap.dedent(
+                """\
+                [pytest]
+                addopts = --verbose
+                """
+            ),
+            encoding="utf-8",
+        )
+
+        config = pytester.parseconfig(tmp_path)
+
+        assert config.option.verbose == config.output_verbosity.verbose
+
+    def test_level_matches_verbost_when_not_specified(
+        self, pytester: Pytester, tmp_path: Path
+    ) -> None:
+        tmp_path.joinpath("pytest.ini").write_text(
+            textwrap.dedent(
+                """\
+                [pytest]
+                addopts = --verbose
+                """
+            ),
+            encoding="utf-8",
+        )
+        pytester.plugins = [TestOutputVerbosity.VerbosityIni()]
+
+        config = pytester.parseconfig(tmp_path)
+
+        assert (
+            config.output_verbosity.verbosity_for(TestOutputVerbosity.SOME_OUTPUT_TYPE)
+            == config.output_verbosity.verbose
+        )
+
+    def test_level_matches_specified_override(
+        self, pytester: Pytester, tmp_path: Path
+    ) -> None:
+        tmp_path.joinpath("pytest.ini").write_text(
+            textwrap.dedent(
+                f"""\
+                [pytest]
+                addopts = --verbose
+                verbosity_{TestOutputVerbosity.SOME_OUTPUT_TYPE} = {TestOutputVerbosity.SOME_OUTPUT_VERBOSITY_LEVEL}
+                """
+            ),
+            encoding="utf-8",
+        )
+        pytester.plugins = [TestOutputVerbosity.VerbosityIni()]
+
+        config = pytester.parseconfig(tmp_path)
+
+        assert (
+            config.output_verbosity.verbosity_for(TestOutputVerbosity.SOME_OUTPUT_TYPE)
+            == TestOutputVerbosity.SOME_OUTPUT_VERBOSITY_LEVEL
+        )