Allow hiding a parameter set from test name (#13229)

Fixes #13228 --------- Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

Author: Anton3

AUTHORS

@@ -43,6 +43,7 @@ Anthony Shaw
 Anthony Sottile
 Anton Grinevich
 Anton Lodder
+Anton Zhilin
 Antony Lee
 Arel Cordero
 Arias Emmanuel

changelog/13228.feature.rst

@@ -0,0 +1,3 @@
+:ref:`hidden-param` can now be used in ``id`` of :func:`pytest.param` or in
+``ids`` of :py:func:`Metafunc.parametrize <pytest.Metafunc.parametrize>`.
+It hides the parameter set from the test name.

doc/en/reference/reference.rst

@@ -20,6 +20,16 @@ The current pytest version, as a string::
  >>> pytest.__version__
  '7.0.0'
 
+.. _`hidden-param`:
+
+pytest.HIDDEN_PARAM
+~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 8.4
+
+Can be passed to ``ids`` of :py:func:`Metafunc.parametrize <pytest.Metafunc.parametrize>`
+or to ``id`` of :func:`pytest.param` to hide a parameter set from the test name.
+Can only be used at most 1 time, as test names need to be unique.
 
 .. _`version-tuple`:
 

src/_pytest/mark/__init__.py

@@ -12,8 +12,10 @@
 
 from .expression import Expression
 from .expression import ParseError
+from .structures import _HiddenParam
 from .structures import EMPTY_PARAMETERSET_OPTION
 from .structures import get_empty_parameterset_mark
+from .structures import HIDDEN_PARAM
 from .structures import Mark
 from .structures import MARK_GEN
 from .structures import MarkDecorator
@@ -33,6 +35,7 @@
 
 
 __all__ = [
+ "HIDDEN_PARAM",
  "MARK_GEN",
  "Mark",
  "MarkDecorator",
@@ -48,7 +51,7 @@
 def param(
  *values: object,
  marks: MarkDecorator | Collection[MarkDecorator | Mark] = (),
- id: str | None = None,
+ id: str | _HiddenParam | None = None,
 ) -> ParameterSet:
  """Specify a parameter in `pytest.mark.parametrize`_ calls or
  :ref:`parametrized fixtures <fixture-parametrize-marks>`.
@@ -72,7 +75,14 @@ def test_eval(test_input, expected):
 
  :ref:`pytest.mark.usefixtures <pytest.mark.usefixtures ref>` cannot be added via this parameter.
 
- :param id: The id to attribute to this parameter set.
+ :type id: str | Literal[pytest.HIDDEN_PARAM] | None
+ :param id:
+ The id to attribute to this parameter set.
+
+ .. versionadded:: 8.4
+ :ref:`hidden-param` means to hide the parameter set
+ from the test name. Can only be used at most 1 time, as
+ test names need to be unique.
  """
  return ParameterSet.param(*values, marks=marks, id=id)
 

src/_pytest/mark/structures.py

@@ -10,6 +10,7 @@
 from collections.abc import MutableMapping
 from collections.abc import Sequence
 import dataclasses
+import enum
 import inspect
 from typing import Any
 from typing import final
@@ -38,6 +39,16 @@
 EMPTY_PARAMETERSET_OPTION = "empty_parameter_set_mark"
 
 
+# Singleton type for HIDDEN_PARAM, as described in:
+# https://www.python.org/dev/peps/pep-0484/#support-for-singleton-types-in-unions
+class _HiddenParam(enum.Enum):
+ token = 0
+
+
+#: Can be used as a parameter set id to hide it from the test name.
+HIDDEN_PARAM = _HiddenParam.token
+
+
 def istestfunc(func) -> bool:
  return callable(func) and getattr(func, "__name__", "<lambda>") != "<lambda>"
 
@@ -68,14 +79,14 @@ def get_empty_parameterset_mark(
 class ParameterSet(NamedTuple):
  values: Sequence[object | NotSetType]
  marks: Collection[MarkDecorator | Mark]
- id: str | None
+ id: str | _HiddenParam | None
 
  @classmethod
  def param(
  cls,
  *values: object,
  marks: MarkDecorator | Collection[MarkDecorator | Mark] = (),
- id: str | None = None,
+ id: str | _HiddenParam | None = None,
  ) -> ParameterSet:
  if isinstance(marks, MarkDecorator):
  marks = (marks,)
@@ -88,8 +99,11 @@ def param(
  )
 
  if id is not None:
- if not isinstance(id, str):
- raise TypeError(f"Expected id to be a string, got {type(id)}: {id!r}")
+ if not isinstance(id, str) and id is not HIDDEN_PARAM:
+ raise TypeError(
+ "Expected id to be a string or a `pytest.HIDDEN_PARAM` sentinel, "
+ f"got {type(id)}: {id!r}",
+ )
  return cls(values, marks, id)
 
  @classmethod

src/_pytest/python.py

@@ -25,6 +25,7 @@
 from typing import Any
 from typing import final
 from typing import Literal
+from typing import NoReturn
 from typing import TYPE_CHECKING
 import warnings
 
@@ -56,7 +57,9 @@
 from _pytest.fixtures import get_scope_node
 from _pytest.main import Session
 from _pytest.mark import ParameterSet
+from _pytest.mark.structures import _HiddenParam
 from _pytest.mark.structures import get_unpacked_marks
+from _pytest.mark.structures import HIDDEN_PARAM
 from _pytest.mark.structures import Mark
 from _pytest.mark.structures import MarkDecorator
 from _pytest.mark.structures import normalize_mark_list
@@ -473,7 +476,7 @@ def _genfunctions(self, name: str, funcobj) -> Iterator[Function]:
  fixtureinfo.prune_dependency_tree()
 
  for callspec in metafunc._calls:
- subname = f"{name}[{callspec.id}]"
+ subname = f"{name}[{callspec.id}]" if callspec._idlist else name
  yield Function.from_parent(
  self,
  name=subname,
@@ -884,7 +887,7 @@ class IdMaker:
  # Used only for clearer error messages.
  func_name: str | None
 
- def make_unique_parameterset_ids(self) -> list[str]:
+ def make_unique_parameterset_ids(self) -> list[str | _HiddenParam]:
  """Make a unique identifier for each ParameterSet, that may be used to
  identify the parametrization in a node ID.
 
@@ -905,6 +908,8 @@ def make_unique_parameterset_ids(self) -> list[str]:
  # Suffix non-unique IDs to make them unique.
  for index, id in enumerate(resolved_ids):
  if id_counts[id] > 1:
+ if id is HIDDEN_PARAM:
+ self._complain_multiple_hidden_parameter_sets()
  suffix = ""
  if id and id[-1].isdigit():
  suffix = "_"
@@ -919,15 +924,21 @@ def make_unique_parameterset_ids(self) -> list[str]:
  )
  return resolved_ids
 
- def _resolve_ids(self) -> Iterable[str]:
+ def _resolve_ids(self) -> Iterable[str | _HiddenParam]:
  """Resolve IDs for all ParameterSets (may contain duplicates)."""
  for idx, parameterset in enumerate(self.parametersets):
  if parameterset.id is not None:
  # ID provided directly - pytest.param(..., id="...")
- yield _ascii_escaped_by_config(parameterset.id, self.config)
+ if parameterset.id is HIDDEN_PARAM:
+ yield HIDDEN_PARAM
+ else:
+ yield _ascii_escaped_by_config(parameterset.id, self.config)
  elif self.ids and idx < len(self.ids) and self.ids[idx] is not None:
  # ID provided in the IDs list - parametrize(..., ids=[...]).
- yield self._idval_from_value_required(self.ids[idx], idx)
+ if self.ids[idx] is HIDDEN_PARAM:
+ yield HIDDEN_PARAM
+ else:
+ yield self._idval_from_value_required(self.ids[idx], idx)
  else:
  # ID not provided - generate it.
  yield "-".join(
@@ -1001,12 +1012,7 @@ def _idval_from_value_required(self, val: object, idx: int) -> str:
  return id
 
  # Fail.
- if self.func_name is not None:
- prefix = f"In {self.func_name}: "
- elif self.nodeid is not None:
- prefix = f"In {self.nodeid}: "
- else:
- prefix = ""
+ prefix = self._make_error_prefix()
  msg = (
  f"{prefix}ids contains unsupported value {saferepr(val)} (type: {type(val)!r}) at index {idx}. "
  "Supported types are: str, bytes, int, float, complex, bool, enum, regex or anything with a __name__."
@@ -1019,6 +1025,21 @@ def _idval_from_argname(argname: str, idx: int) -> str:
  and the index of the ParameterSet."""
  return str(argname) + str(idx)
 
+ def _complain_multiple_hidden_parameter_sets(self) -> NoReturn:
+ fail(
+ f"{self._make_error_prefix()}multiple instances of HIDDEN_PARAM "
+ "cannot be used in the same parametrize call, "
+ "because the tests names need to be unique."
+ )
+
+ def _make_error_prefix(self) -> str:
+ if self.func_name is not None:
+ return f"In {self.func_name}: "
+ elif self.nodeid is not None:
+ return f"In {self.nodeid}: "
+ else:
+ return ""
+
 
 @final
 @dataclasses.dataclass(frozen=True)
@@ -1047,7 +1068,7 @@ def setmulti(
  *,
  argnames: Iterable[str],
  valset: Iterable[object],
- id: str,
+ id: str | _HiddenParam,
  marks: Iterable[Mark | MarkDecorator],
  scope: Scope,
  param_index: int,
@@ -1065,7 +1086,7 @@ def setmulti(
  params=params,
  indices=indices,
  _arg2scope=arg2scope,
- _idlist=[*self._idlist, id],
+ _idlist=self._idlist if id is HIDDEN_PARAM else [*self._idlist, id],
  marks=[*self.marks, *normalize_mark_list(marks)],
  )
 
@@ -1190,6 +1211,11 @@ def parametrize(
  They are mapped to the corresponding index in ``argvalues``.
  ``None`` means to use the auto-generated id.
 
+ .. versionadded:: 8.4
+ :ref:`hidden-param` means to hide the parameter set
+ from the test name. Can only be used at most 1 time, as
+ test names need to be unique.
+
  If it is a callable it will be called for each entry in
  ``argvalues``, and the return value is used as part of the
  auto-generated id for the whole set (where parts are joined with
@@ -1322,7 +1348,7 @@ def _resolve_parameter_set_ids(
  ids: Iterable[object | None] | Callable[[Any], object | None] | None,
  parametersets: Sequence[ParameterSet],
  nodeid: str,
- ) -> list[str]:
+ ) -> list[str | _HiddenParam]:
  """Resolve the actual ids for the given parameter sets.
 
  :param argnames:

src/pytest/__init__.py

@@ -33,6 +33,7 @@
 from _pytest.logging import LogCaptureFixture
 from _pytest.main import Dir
 from _pytest.main import Session
+from _pytest.mark import HIDDEN_PARAM
 from _pytest.mark import Mark
 from _pytest.mark import MARK_GEN as mark
 from _pytest.mark import MarkDecorator
@@ -89,6 +90,7 @@
 
 
 __all__ = [
+ "HIDDEN_PARAM",
  "Cache",
  "CallInfo",
  "CaptureFixture",